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Psychosocial Correlates of Symptoms in Functional Dyspepsia
CLINICAL GASTROENTEROLOGY AND HEPATOLOGY 2005;3:521–528
Psychosocial Correlates of Symptoms in Functional Dyspepsia MICHAEL P. JONES,* LISA K. SHARP,‡ and MICHAEL D. CROWELL§ *Division of Gastroenterology, ‡Department of Family Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; and § Division of Gastroenterology, Mayo Clinic, Scottsdale, Arizona
Background & Aims: Psychosocial factors may influence both symptom generation and reporting in functional dyspepsia. We determined the presence and severity of these factors as well as their relationship to dyspeptic symptoms in patients with functional dyspepsia and healthy subjects. Methods: A total of 151 consecutive patients with functional dyspepsia referred chiefly from primary care clinics and 90 healthy subjects rated 15 dyspeptic symptoms. Participants completed the Medical Outcomes Study SF-36 and Symptom Checklist-90 –revised. Results: Functional dyspepsia patients reported significantly higher symptom scores, poorer quality of life, and greater psychiatric distress than healthy subjects. For both patients and healthy subjects, increasing symptom scores were associated with significant decreases in the Physical but not the Mental Components Summary of the Medical Outcomes Study SF-36. Although functional dyspepsia patients showed significantly greater psychiatric distress than healthy subjects, symptoms were correlated only modestly with scores on the Symptom Checklist-90 –revised. A number of symptoms showed significant but modest correlations (rs < .30) with the somatization scale with chest burning correlating most strongly (rs ⴝ .48). Chest burning also was correlated significantly with depression, anxiety, and phobic anxiety. Functional dyspepsia patients at a secondary level of care have greater symptom severity, poorer quality of life, and greater psychiatric distress than healthy subjects. Increasing symptom severity is associated with poorer quality of life primarily in the areas of physical and social functioning. With the exception of chest burning, symptoms are not correlated highly with psychiatric distress. Conclusions: These data suggest that although functional dyspepsia patients experience increased psychiatric distress, symptom severity and psychiatric distress are not associated strongly.
unctional gastrointestinal disorders are medically unexplained symptoms commonly encountered in the general community and associated with reduced quality of life and increased health care resource use and expenses.1– 4 Presently, these disorders appear best explained by a biopsychosocial model of illness; although the exact role of psychosocial factors is not yet clear.5,6
F
Psychosocial factors have been felt to influence digestive symptoms in either 1 of 2 ways. Some investigators have felt that psychosocial factors are causative in symptom generation. The greatest support for this argument comes from studies documenting a high prevalence of comorbid psychiatric diagnoses in patients with functional digestive disorders.7–10 The greatest criticism of this line of reasoning is that the majority of evidence comes from referral populations containing refractory patients predisposed to have a high prevalence of psychiatric illness. The second way in which psychosocial factors influence symptoms in functional gastrointestinal disorders is through enhanced health care seeking. Several studies have shown that compared with dyspeptic nonconsulters, consulters have greater degrees of psychiatric distress, greater somatization, and less-adaptive coping styles.11–15 Psychosocial variables known to influence symptom reporting include coping styles, anxiety, depression, life stress, neuroticism, illness behavior, and somatization.11,12,16 –18 Somatization, in particular, is an extremely relevant variable in symptom provocation studies. Somatization is a complex construct that is defined variably. We use the definition put forth by Lipowski19 because it is used and endorsed widely in the behavioral literature. According to Lipowski,19 somatization is the tendency to express emotional dysphoria as physical symptoms. Although the causes of somatization are multifactorial, an associated psychiatric disorder (often anxiety or depression) is encountered commonly.19,20 Although the role of psychiatric illness in irritable bowel syndrome has been addressed extensively, the literature on psychosocial correlates in functional dyspepsia is not as mature.21 The aim of the present investigation was 2-fold. First, we sought to characterize relevant psychosocial variables and quality of life in a population of patients with functional dyspepsia primarily referred from a primary care clinic as compared with healthy © 2005 by the American Gastroenterological Association
1542-3565/05/$30.00 PII: 10.1053/S1542-3565(05)00245-4
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controls. Second, we sought to correlate these psychosocial variables with specific dyspeptic symptoms. The a priori hypothesis was that if dyspeptic symptoms represented the physical manifestations of various aspects of psychiatric distress (ie, somatization), there should be correlations between specific symptoms, measures of somatization, and specific psychosocial variables.
Materials and Methods Patients with functional dyspepsia were recruited consecutively after being evaluated by the principal investigator (M.P.J.). Ninety percent of these patients either were referred from a primary care physician or were self-referred. The remaining 10% were referred by another gastroenterologist. Two thirds of recruited patients were enrolled. Functional dyspepsia was defined using Rome II criteria for functional dyspepsia (Table 1).22 Patients with functional dyspepsia were categorized further as ulcer-like dyspepsia or dysmotility-like dyspepsia by using Rome II guidelines. Patients were considered to have ulcer-like dyspepsia if the predominant symptom was pain centered in the upper abdomen. Patients were considered to have dysmotility-like dyspepsia if their predominant symptom was a nonpainful sensation characterized or associated with upper-abdominal fullness, early satiety, bloating, or nausea. The predominant symptom was ascertained by direct query regarding the patient’s most bothersome symptom. Patients were excluded if they had dominant complaints of heartburn, prior digestive surgery other than cholecystectomy or appendectomy, or were taking medications known or suspected of altering digestive motility. A patient was considered to have a dominant complaint of heartburn if that patient declared heartburn to be the most bothersome symptom. All patients were required to have a normal upper-gastrointestinal endoscopy with further evaluation performed as indicated by the evaluating gastroenterologist. Healthy patients not receiving care for digestive disorders and not using medications to treat digestive symptoms were recruited as controls by advertisement. Controls also were excluded if they had prior digestive surgery other than cholecystectomy or appendectomy or used medications known commonly to cause adverse digestive symptoms or affect digestive motility. The study was approved by the Institutional Review
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Board of Northwestern University and all patients provided informed consent.
Questionnaires Participants completed several self-report measures pertaining to symptomatology and psychologic traits. Dyspeptic symptoms were evaluated using the symptom assessment portion of the Nepean Dyspepsia Index, which queries symptoms over the 2 weeks before administration.23,24 Fifteen common dyspeptic symptoms were queried specifically by using a Likert scale that evaluated the frequency, intensity, and intrusiveness of each symptom. The scores for frequency, intensity, and intrusiveness were summed to give a score for each symptom that could range from 0 to 13, with higher values representing greater symptom severity. The total symptom score was calculated as the sum of the scores for all individual scores and could range from 0 to 195. The patient’s general quality of life was assessed by using the Medical Outcomes Study SF-36 (SF-36).25–27 The SF-36 is a well-studied, valid instrument that has been used to determine general quality of life in a variety of clinical settings including functional gastrointestinal disorders.27–30 This measure assesses 8 health concepts: (1) limitations in physical activities because of health problems; (2) limitations in social activities because of physical or emotional problems; (3) limitations in usual role activities because of physical health problems; (4) bodily pain; (5) general mental health (psychologic distress and well-being); (6) limitations in usual role activities because of emotional problems; (7) vitality (energy and fatigue); and (8) general health perceptions. Physical and mental composite summaries represent the weighted aggregate scores of relevant scales transformed into t-scores. Lower scores indicate poorer quality of life. Psychiatric distress was measured using the total score of the Symptom Checklist-90 –Revised (SCL-90 –R), which is a selfreport, clinical symptom rating scale consisting of 90 symptoms associated with 9 psychiatric constructs.31 These constructs are somatization, obsessive-compulsive behavior, feelings of inadequacy or inferiority (interpersonal sensitivity), depression, anxiety, hostility, phobic anxiety, paranoid ideation, and psychoticism. The total score for the measure was reported as a raw value whereas the scale scores were converted into t scores by using published values for healthy outpatients.
Table 1. Rome II Diagnostic Criteria for Functional Dyspepsia Including Ulcer-Like and Dysmotility-Like Subgroups At least 12 weeks, which need not be consecutive, within the preceding 12 months of: Persistent or recurrent dyspepsia (pain or discomfort centered in the upper abdomen); and No evidence of organic disease (including at upper endoscopy) that is likely to explain the symptoms; and No evidence that dyspepsia is exclusively relieved by defecation or associated with the onset of a change in stool frequency or stool form (ie, not irritable bowel); and Pain centered in the upper abdomen as the predominant (most bothersome) symptom. NOTE. The following definitions were used: ulcer-like dyspepsia, pain centered in the upper abdomen is the predominant (most bothersome) symptom; dysmotility-like dyspepsia, an unpleasant or troublesome nonpainful sensation (discomfort) centered in the upper abdomen is the predominant symptom; this sensation may be characterized by or associated with upper-abdominal fullness, early satiety, bloating, or nausea. Data from Talley et al.22
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Healthy Subject Characteristics Ninety healthy subjects also completed the surveys. The median age of this group was 36 years (range, 27– 45 y) and the group included 61 women and 29 men. The groups did not differ significantly with respect to age (P ⫽ .80) or sex (P ⫽ .09), although the control group did contain more men. Dyspepsia Symptom Scores
Figure 1. Scores for individual symptom queried by the Nepean Dyspepsia Index. Columns represent median values and error bars represent the interquartile range. Each symptom was rated for its frequency, severity, and bothersomeness. The scores for these 3 symptom characteristics were summed to give a total symptom score that could range from 0 to 13 points.
Statistical Analysis The normality of all datasets was determined using the Kolmogorov–Smirnov test. Because some of the data were not distributed normally, all data were expressed as medians (25th–75th percentile) for purposes of consistency. For normally distributed data, correlations were calculated using the Pearson method and differences between groups were determined using unpaired t tests. Correlations between non–normally distributed or categoric datasets were determined using the Spearman method whereas differences between median group scores were determined using the Mann–Whitney test. Statistical significance was set at P ⬍ .05. Statistical calculations were performed using GraphPad Prism version 3.00 for Windows (GraphPad Software, San Diego, CA).
Results Patient Characteristics A total of 151 patients with functional dyspepsia completed the survey. The median (25th–75th percentile) age was 35 years (range, 27– 46 y) and the group included 118 women and 33 men. Twenty-five patients (17%) had upper-abdominal pain as a dominant symptom and were classified as having ulcer-like dyspepsia. The remaining 126 patients (83%) were classified as having dysmotility-like dyspepsia. Because the number of patients with ulcer-like dyspepsia was small, comparisons were not made between patients with ulcer-like and dysmotility-like dyspepsia. Similarly, comparisons were not made between patients referred from primary care clinics or gastroenterologists or between physician-referred vs self-referred patients because of the small number in the self-referred or gastroenterologist-referred groups.
The median total dyspepsia symptom score was 78 (range, 51–112) for patients with functional dyspepsia and 3 (range, 0 – 6) for controls (P ⬍ .0001). Scores for the 15 queried symptoms in the patients with functional dyspepsia are shown in Figure 1. Although most patients were classified as having dysmotility-like dyspepsia based on dominant symptoms of upper-abdominal discomfort rather than pain, symptom scores for pain and discomfort were correlated highly (rs ⫽ .69; P ⬍ .0001). Quality-of-Life Scores Compared with control patients, quality of life as measured by the SF-36 was diminished in patients with functional dyspepsia (Figure 2). Patients with functional dyspepsia had significantly lower scores on all scales of the SF-36 (P ⬍ .0001 for all). Additionally, both physical and mental component summary scores likewise were reduced. For patients with functional dyspepsia, the median physical component summary score was 36 (range, 25– 49) and the median mental component summary score was 33 (range, 25– 42). This was significantly lower than the control group in which the median physical component summary score was 58 (range, 57–59) and the median mental component summary score was 47 (range, 43–50) (P ⬍ .0001 for both). Psychiatric Distress Patients with functional dyspepsia endorsed responses on the SCL-90 –R indicating increased levels of
Figure 2. Quality of life as measured by the SF-36. Patients with functional dyspepsia () had significantly lower scores (P ⬍ .0001) on all scales of the SF-36 compared with healthy patients (□). Columns represent median values and error bars reflect the interquartile range. PF, physical functioning; RP, role-physical; BP, bodily pain; SF, social functioning; MH, mental health; RE, role-emotional; VT, vitality; GH, general health.
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Figure 3. SCL-90 –R scores for healthy patients and patients with functional dyspepsia. The t-scores for patients with dyspepsia () differed significantly (P ⬍ .0001) from those of healthy patients (□) on all scales. Columns represent median values, and error bars are the interquartile range. Obs-compuls, obsessive-compulsive; inter. sens., interpersonal sensitivity. phob. anxiety, phobic anxiety; para. ideation, paranoid ideation.
psychiatric distress. The median total score for patients with dyspepsia was 53 (30 – 89) compared with 9 (4 –20) for healthy patients (P ⬍ .0001). The t-scores for each of the 8 scales are shown in Figure 3. Compared with healthy patients, the patients with functional dyspepsia scored significantly higher (P ⬍ .0001) on all SCL-90 –R scales. Association of Dyspeptic Symptoms and Quality of Life For patients with functional dyspepsia, the total dyspeptic symptom score significantly correlated with the SF-36 physical component summary score (rs ⫽ ⫺.46; P ⬍ .0001) but not with the mental component summary score (rs ⫽ .12; P ⫽ .23). For healthy patients, no significant correlations existed with either the physical component summary score (rs ⫽ ⫺.24; P ⫽ .13) or the mental component summary score (rs ⫽ ⫺.16; P ⫽ .33). Among patients with dyspepsia, significant correlations existed with individual scale scores for bodily pain (rs ⫽ ⫺.51; P ⬍ .0001), physical functioning (rs ⫽ ⫺.41; P ⬍ .0001), social functioning (rs ⫽ ⫺.37; P ⬍ .0001), vitality (rs ⫽ ⫺.27; P ⫽ .0045), and physical role (rs ⫽ ⫺.25; P ⫽ .009). No significant correlations existed between the total dyspeptic symptom score and scores on the general health, mental health, and emotional role scales. Association of Dyspeptic Symptoms and Psychiatric Distress Patients with functional dyspepsia displayed a modest but significant correlation between the dyspeptic symptom score and the total score on the SCL-90 –R (rs ⫽ .24; P ⫽ .0117). Among patients with dyspepsia, we sought to determine whether the correlations between total dyspeptic symptom scores and psychiatric distress might be greater in patients with more severe psychiatric distress. The
lower and upper tertiles for the SCL-90 –R total scores were analyzed separately. The Spearman correlations between the total dyspeptic symptom score and SCL-90 –R scores in the lower tertile and upper tertile were .28 (P ⫽ .29) and .25 (P ⫽ .376). Total dyspeptic symptom scores were higher for the upper tertile group (95; range, 64 – 114) than for the lower tertile group (73; 40 –98) but these differences did not achieve statistical significance (P ⫽ .1). Among patients with dyspepsia, the strongest correlation between dyspeptic symptom scores and SCL-90 –R scale scores existed with somatization (rs ⫽ .51; P ⬍ .0001). Modest but significant correlations also existed with the phobic anxiety (rs ⫽ .22; P ⫽ .0199) and anxiety scales (rs ⫽ .20; P ⫽ .035). Association of Specific Dyspeptic Symptoms With Quality of Life and Psychiatric Distress For patients with functional dyspepsia, the relationships between specific dyspeptic symptoms, total SCL-90 –R score, SCL-90 –R scale scores, and SF-36 scores also were explored. In this analysis only data from subjects endorsing a specific symptom were included to identify how endorsing a symptom differentially impacted quality of life. The relationship between specific dyspeptic symptoms and SF-36 scores is shown in Table 2. In general, symptoms were associated with decrements in the physical rather than mental aspects of quality of life. Ten of 15 symptoms had significant modest inverse correlations with the bodily pain scale of the SF-36. Seven of 15 symptoms also had significant modest inverse correlations with the social functioning scale. Eight of 15 symptoms showed significant correlations with summary component scores, and 7 of 8 of these symptoms were correlated significantly with the physical component summary score. Only chest burning was correlated sig-
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nificantly with the mental component summary score, which largely was attributable to its significant inverse correlations with mental health, emotional role, and vitality in addition to a positive correlation with abdominal pain. The association of chest burning with decrements in the emotional aspects of quality of life is supported by significant correlations of symptom scores for chest burning with the total SCL-90 –R score as well as scale scores for somatization, depression, anxiety, phobic anxiety, and psychoticism (Table 3). Although 6 other symptoms had significant correlations with somatization, there were few other significant correlations with any other subscale scores and none explained more than 15% of the variance. Although correlations of symptoms with somatization were the strongest correlations seen with the SCL90 –R scales, these correlations were modest and explained only 7%–23% of the variance.
Discussion Compared with healthy patients, the patients with functional dyspepsia had significantly greater scores for dyspeptic symptoms, significantly greater psychiatric distress as measured by the SCL-90 –R, and significantly poorer quality of life as measured by the SF-36. Overall, symptom severity as measured by both scores for individual symptoms or the total dyspepsia symptom score correlated poorly with both the total score and scale scores on the SCL-90 –R. The symptom of chest burning was the greatest exception to this finding. Forty-five patients (30% of our sample) acknowledged this symptom. Of the 15 dyspeptic symptoms queried, this symptom was the most highly correlated with the total SCL90 –R score (rs ⫽ .44; P ⫽ .001) and was also the symptom most highly correlated with the scale scores for somatization, depression, anxiety, phobic anxiety, and psychoticism. Importantly, chest burning was also the only symptom significantly correlated with impairments in the mental component summary of the SF-36 (rs ⫽ ⫺.47; P ⬍ .001). The lack of an association between psychiatric distress and symptom severity (with the exception of burning chest pain) argues against a role for somatization as defined by Lipowski19 and others.20 Although several symptoms had modest, statistically significant associations with the somatization scale of the SCL-90 –R, it should be pointed out that 3 of the 12 items on the somatization scale pertain to digestive function. These include pain in the heart or chest, nausea or upset stomach, and lump in your throat. Because of this, the somatization scale of the SCL-90 –R may tend to over-
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estimate the role of somatization in patients with digestive disorders. We purposely did not remove these items from the survey because we did not wish to compromise the structure of the instrument. We recently have published data showing that in patients with functional dyspepsia, there is a statistically significant but clinically modest increase in scores for somatosensory amplification.32 Thus, although somatization is clearly a cause of symptoms in some patients with functional digestive disorders, it is not a dominant mechanism across a population of patients with dyspeptic symptoms. Dyspeptic symptom severity most strongly correlated with changes on the physical component summary of the SF-36. The most profound differences with respect to quality of life exist in elements associated with physical role and social functioning. The exception to this, as previously mentioned, was burning chest pain that was not correlated with the physical component summary (rs ⫽ ⫺.10; P ⫽ .50) but was significantly correlated with the mental component summary (rs ⫽ ⫺.47; P ⬍ .0001). If psychiatric distress was associated more strongly with dyspeptic symptoms, we would have expected greater associations between symptom scores and factors associated with the mental component summary of the SF-36. This study has evaluated associations between reported dyspeptic symptom severity, quality of life, and psychiatric distress. It cannot define mechanistic relationships between these variables and caution is necessary in interpreting the absence of a relationship between psychiatric distress and dyspeptic symptoms because a type II error is possible. However, the fact that we did confirm the often-reported association of chest pain and psychiatric distress makes a type II error less likely. Additionally, functional dyspepsia is not a homogenous disorder and it is likely that there are subgroups of patients with functional dyspepsia having different symptom causes.33 Our methods of assessment did not allow us to address this and a substantially larger sample size would be needed to use factor analysis using these measures. The present study had several limitations. Patients were recruited from a single clinic and recruitment was consecutive but enrollment was not. Patients not wishing to participate may have differed from those choosing to complete the surveys. We did not pursue a formal psychiatric evaluation or detailed psychiatric history in our patients. Formal diagnostic interviews for psychopathology, particularly somatoform disorders, would have added useful information that might have influenced the interpretation of our data. Additionally, we did not assess
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Table 2. Correlation of Specific Dyspeptic Symptoms With Alterations in Quality of Life Symptom (n)
PCS
MCS
PF
RP
Pain in upper abdomen (81) Discomfort in upper abdomen (88) Burning in upper abdomen (45) Chest burning (49) Cramps (44) Chest pain (42) Inability to finish meal (82) Regurgitation (62) Fullness/slow digestion (99) Pressure in upper abdomen (62) Bloating in upper abdomen (79) Nausea (91) Burping/belching (81) Vomiting (55) Bad breath (47)
⫺.44 (⬍.001) ⫺.38 (⬍.001) ⫺.24 (.11) ⫺.10 (.50) ⫺.32 (.03) ⫺.14 (.39) ⫺.30 (.007) ⫺.17 (.20) ⫺.26 (.01) ⫺.19 (.14) .08 (.51) ⫺.30 (.004) ⫺.14 (.20) ⫺.30 (.02) ⫺.23 (.13)
⫺.06 (.61) ⫺.003 (.98) ⫺.11 (.48) ⫺.47 (⬍.001) .26 (.08) ⫺.16 (.30) .11 (.31) ⫺.03 (.80) .10 (.30) ⫺.01 (.94) .14 (.20) .10 (.35) .06 (.61) .16 (.24) ⫺.23 (.12)
⫺.37 (⬍.001) ⫺.22 (.04) ⫺.053 (.73) .074 (.62) ⫺.26 (.09) ⫺.07 (.66) ⫺.20 (.07) ⫺.14 (.28) ⫺.28 (.01) ⫺.18 (.17) .04 (.72) ⫺.22 (.03) ⫺.10 (.36) .32 (.02) ⫺.10 (.51)
⫺.32 (.003) ⫺.26 (.013) ⫺.13 (.41) ⫺.16 (.27) ⫺.16 (.28) ⫺.05 (.75) ⫺.15 (.18) ⫺.09 (.51) ⫺.12 (.23) ⫺.10 (.43) .08 (.46) ⫺.21 (.05) ⫺.04 (.70) .001 (.99) ⫺.31 (.03)
NOTE. Increasing symptom severity generally is associated with decreases in physical composite summary scores largely attributable to decreases in bodily pain scores. A notable exception is chest burning, which is associated primarily with significant reductions in mental composite summary scores. Data are expressed as rs (p). PCS, physical component summary; MCS, mental component summary; PF, physical functioning; RP, role-physical; BP, bodily pain; GH, general health; SF, social functioning; MH, mental health; RE, role-emotional; VT, vitality.
extraintestinal symptoms. Patients with somatized distress often have increased extraintestinal as well as evolving or migrating pains. Assessing for extraintestinal symptoms would have strengthened our assessment. Although we chose the survey instruments used because they are valid, reproducible measures that have been used widely in a variety of clinical scenarios including functional digestive disorders, they do have limitations. It has been questioned whether the use of the SCL-90 –R may be limited beyond being a measure of general psychiatric distress.34,35 A number of other studies, however, have supported the validity of the SCL90 –R scales.36,37 Because of these concerns, we have
limited our interpretations to those based on the relationships between the total SCL-90 –R score and symptoms and have included scale scores and relationships in the results for completeness. This study should not be construed as an attempt to create an SCL-90 –R profile for patients with functional dyspepsia. Finally, it could be argued that functional dyspepsia simply represents a chronic pain syndrome and that because the SF-36 and SCL-90 –R contain questions relating to pain, these measures would produce a biased response. However, the study population was comprised primarily of patients with motility-like dyspepsia and, as is shown in Figure 1, pain was only the fifth highest
Table 3. Correlation of Specific Dyspeptic Symptoms With SCL-90 –R Scale Scores Symptom (n)
Total score
Somatization
Obsessivecompulsive
Interpers sensitivity
Pain in upper abdomen (75) Discomfort in upper abdomen (82) Burning in upper abdomen (40) Chest burning (45) Cramps (39) Chest pain (38) Inability to finish meal (77) Regurgitation (57) Fullness/slow digestion (92) Pressure in upper abdomen (58) Bloating in upper abdomen (75) Nausea (85) Burping/belching (76) Vomiting (52) Bad breath (32)
.21 (.05) .23 (.03) .34 (.02) .47 (.001) ⫺.12 (.45) .26 (.10) ⫺.04 (.73) .29 (.02) .20 (.04) .17 (.17) .07 (.53) .02 (.89) .13 (.24) .01 (.99) .27 (.06)
.28 (.02) .25 (.02) .28 (.08) .48 (⬍.001) .15 (.36) .41 (.01) .17 (.14) .27 (.04) .30 (.003) .28 (.03) ⫺.03 (.81) .16 (.15) .22 (.05) .17 (.22) ⫺.04 (.79)
.07 (.54) .09 (.41) .17 (.30) .10 (.52) ⫺.11 (.52) .07 (.68) ⫺.08 (.47) .01 (.92) .01 (.92) .12 (.37) ⫺.22 (.06) ⫺.05 (.64) .002 (.98) ⫺.09 (.52) .10 (.51)
⫺.01 (.94) .01 (.94) .13 (.43) .21 (.17) ⫺.14 (.39) .10 (.56) ⫺.05 (.67) .03 (.81) .03 (.79) .05 (.73) ⫺.03 (.80) ⫺.23 (.03) ⫺.12 (.29) ⫺.17 (.23) ⫺.02 (.88)
NOTE. Increasing symptom severity is significantly but modestly associated with somatization. Only chest burning has significant scale associations. Severity scores for other symptoms are not significantly correlated with measures of psychiatric distress. Data are expressed as rs (P).
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Table 2. (continued) BP
GH
SF
MH
RE
VT
⫺.41 (⬍.001) ⫺.40 (⬍.001) ⫺.34 (.02) ⫺.34 (.02) ⫺.31 (.04) ⫺.32 (.04) ⫺.31 (.01) ⫺.20 (.12) ⫺.36 (⬍.001) ⫺.21 (.11) .10 (.37) ⫺.29 (.005) ⫺.15 (.17) ⫺.31 (.02) ⫺.29 (.05)
⫺.18 (.12) ⫺.04 (.75) .03 (.83) ⫺.37 (.008) ⫺.02 (.89) ⫺.10 (.53) .04 (.72) ⫺.04 (.74) ⫺.06 (.54) ⫺.04 (.77) .02 (.83) ⫺.04 (.68) .04 (.70) ⫺.03 (.84) ⫺.13 (.38)
⫺.39 (⬍.001) ⫺.40 (⬍.001) ⫺.25 (.09) ⫺.24 (.10) ⫺.16 (.30) ⫺.03 (.83) ⫺.23 (.04) ⫺.22 (.08) ⫺.21 (.04) ⫺.17 (.19) .06 (.59) ⫺.40 (⬍.001) ⫺.18 (.11) ⫺.34 (.01) ⫺.25 (.09)
⫺.10 (.36) ⫺.14 (.20) ⫺.23 (.14) ⫺.34 (.02) .07 (.67) ⫺.15 (.35) .08 (.47) ⫺.18 (.17) .03 (.79) ⫺.09 (.46) .06 (.62) .07 (.52) .01 (.95) .04 (.78) ⫺.29 (.046)
⫺.16 (.15) ⫺.12 (.27) ⫺.11 (.47) ⫺.29 (.04) .21 (.16) ⫺.22 (.17) .06 (.57) ⫺.18 (.15) .04 (.67) ⫺.06 (.63) .23 (.046) .01 (.90) .03 (.79) .04 (.78) ⫺.20 (.19)
⫺.23 (.04) ⫺.14 (.19) ⫺.24 (.12) ⫺.43 (.002) .025 (.87) ⫺.14 (.37) ⫺.16 (.15) ⫺.04 (.77) ⫺.14 (.18) ⫺.10 (.46) .10 (.38) .10 (.35) ⫺.08 (.48) ⫺.01 (.94) ⫺.35 (.02)
scoring symptom. Although there may be limitations to the use of the SF-36 and SCL-90 –R in patients with dominant complaints of chronic pain, the majority of patients with motility-like dyspepsia do not endorse symptoms of abdominal pain. In summary, the current study shows that patients with functional dyspepsia at a secondary level of care have both enhanced symptomatology and psychiatric distress but that the 2 generally are not correlated. The exception to this observation appears to be the symptom of chest burning with anxiety and phobic anxiety. The impact of symptomatology is seen most profoundly on the physical and social aspects of functioning without
much disturbance in mental or emotional aspects. The findings of this study should be of particular relevance to both primary care physicians and gastroenterologists in community practice because the vast majority of these patients came from primary care clinics and were not seen previously by a gastroenterologist. This is a level of care underinvestigated in the clinical investigation of functional digestive disorders in general and functional dyspepsia in particular. These data suggest that digestive symptoms at this level of care are unlikely to represent physically manifested emotional distress. It also seems unlikely that emotional distress is a consequence of dyspeptic symptoms. Rather, it seems that dyspeptic symp-
Table 3. (continued) Depression
Anxiety
Anger-hostility
Phobic anxiety
Paranoid ideation
Psychoticism
.22 (.06) .23 (.04) .29 (.07) .34 (.02) ⫺.11 (.50) .21 (.20) .06 (.60) .18 (.19) .09 (.39) .15 (.26) ⫺.06 (.60) ⫺.05 (.68) ⫺.07 (.56) ⫺.18 (.20) .10 (.51)
.15 (.20) .14 (.21) .38 (.02) .39 (.01) .04 (.80) .25 (.14) ⫺.05 (.67) .13 (.32) .09 (.40) .22 (.09) ⫺.10 (.37) .06 (.61) .01 (.93) .05 (.71) .27 (.08)
⫺.01 (.91) .02 (.84) .10 (.56) .19 (.21) ⫺.15 (.36) .06 (.74) ⫺.06 (.61) ⫺.04 (.78) ⫺.02 (.84) .06 (.64) ⫺.08 (.47) ⫺.13 (.23) .01 (.93) .06 (.70) .11 (.47)
.24 (.04) .25 (.03) .23 (.16) .32 (.03) ⫺.002 (.99) .18 (.29) .07 (.53) .16 (.24) .15 (.16) .21 (.12) .03 (.81) .08 (.47) .07 (.53) .09 (.52) .19 (.22)
⫺.02 (.85) ⫺.03 (.82) .09 (.57) .26 (.08) ⫺.25 (.12) .25 (.13) .04 (.71) .07 (.62) ⫺.01 (.92) .004 (.97) ⫺.10 (.39) ⫺.28 (.01) ⫺.12 (.30) ⫺.06 (.67) .12 (.45)
.10 (.38) .16 (.16) .29 (.07) .32 (.03) ⫺.09 (.58) .21 (.20) .01 (.96) .10 (.48) .04 (.73) .07 (.59) ⫺.12 (.30) ⫺.01 (.93) ⫺.03 (.83) ⫺.002 (.99) .22 (.16)
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toms in this population are occurring against a background of concomitant psychiatric distress.
References 1. Drossman DA, Li Z, Andruzzi E, et al. U.S. householder survey of functional gastrointestinal disorders. Prevalence, sociodemography, and health impact. Dig Dis Sci 1993;38:1569 –1580. 2. Koloski NA, Talley NJ, Boyce PM. Epidemiology and health care seeking in the functional GI disorders: a population-based study. Am J Gastroenterol 2002;97:2290 –2299. 3. Talley NJ, Gabriel SE, Harmsen WS, et al. Medical costs in community subjects with irritable bowel syndrome. Gastroenterology 1995;109:1736 –1741. 4. Whitehead WE, Burnett CK, Cook EW 3rd, et al. Impact of irritable bowel syndrome on quality of life. Dig Dis Sci 1996;41: 2248 –2253. 5. Drossman DA, Creed FH, Olden KW, et al. Psychosocial aspects of the functional gastrointestinal disorders. Gut 1999;45(Suppl 2):II25–II30. 6. Cassileth BR, Drossman DA. Psychosocial factors in gastrointestinal illness. Psychother Psychosom 1993;59:131–143. 7. Haug TT, Svebak S, Wilhelmsen I, et al. Psychological factors and somatic symptoms in functional dyspepsia. A comparison with duodenal ulcer and healthy controls. J Psychosom Res 1994; 38:281–291. 8. Wilhelmsen I, Haug TT, Ursin H, et al. Discriminant analysis of factors distinguishing patients with functional dyspepsia from patients with duodenal ulcer. Significance of somatization. Dig Dis Sci 1995;40:1105–1111. 9. Stanghellini V. Relationship between upper gastrointestinal symptoms and lifestyle, psychosocial factors and comorbidity in the general population: results from the Domestic/International Gastroenterology Surveillance Study (DIGEST). Scand J Gastroenterol Suppl 1999;231:29 –37. 10. Walker EA, Katon WJ, Jemelka RP, et al. Comorbidity of gastrointestinal complaints, depression, and anxiety in the Epidemiologic Catchment Area (ECA) Study. Am J Med 1992;92:26S–30S. 11. Cheng C, Hui WM, Lam SK. Coping style of individuals with functional dyspepsia. Psychosom Med 1999;61:789 –795. 12. Cheng C. Seeking medical consultation: perceptual and behavioral characteristics distinguishing consulters and nonconsulters with functional dyspepsia. Psychosom Med 2000;62:844 – 852. 13. Herschbach P, Henrich G, von Rad M. Psychological factors in functional gastrointestinal disorders: characteristics of the disorder or of the illness behavior? Psychosom Med 1999; 61:148 –153. 14. Meineche-Schmidt V, Krag E. Dyspepsia in general practice in Denmark. A 1-year analysis of consulters in general practice. Scand J Prim Health Care 1998;16:216 –221. 15. Lydeard S, Jones R. Factors affecting the decision to consult with dyspepsia: comparison of consulters and non-consulters. J R Coll Gen Pract 1989;39:495– 498. 16. Sandler RS, Drossman DA, Nathan HP, et al. Symptom complaints and health care seeking behavior in subjects with bowel dysfunction. Gastroenterology 1984;87:314 –318. 17. Norton GR, Norton PJ, Asmundson GJ, et al. Neurotic butterflies in my stomach: the role of anxiety, anxiety sensitivity and depression in functional gastrointestinal disorders. J Psychosom Res 1999;47:233–240. 18. Wiklund I, Butler-Wheelhouse P. Psychosocial factors and their role in symptomatic gastroesophageal reflux disease and functional dyspepsia. Scand J Gastroenterol Suppl 1996;220: 94 –100.
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19. Lipowski ZJ. Somatization: the concept and its clinical application. Am J Psychiatry 1988;145:1358 –1368. 20. Mayou R. Somatization. Psychother Psychosom 1993;59: 69 – 83. 21. Olden KW. Are psychosocial factors of aetiological importance in functional dyspepsia? Baillieres Clin Gastroenterol 1998;12: 557–571. 22. Talley NJ, Stanghellini V, Heading RC, et al. Functional gastroduodenal disorders. Gut 1999;45(Suppl 2):II37–II42. 23. Talley NJ, Haque M, Wyeth JW, et al. Development of a new dyspepsia impact scale: the Nepean Dyspepsia Index. Aliment Pharmacol Ther 1999;13:225–235. 24. Talley NJ, Verlinden M, Jones M. Validity of a new quality of life scale for functional dyspepsia: a United States multicenter trial of the Nepean Dyspepsia Index. Am J Gastroenterol 1999; 94:2390 –2397. 25. Ware JE Jr, Sherbourne CD. The MOS 36-item short-form health survey (SF-36). I. Conceptual framework and item selection. Med Care 1992;30:473– 483. 26. McHorney CA, Ware JE Jr, Lu JF, et al. The MOS 36-item ShortForm Health Survey (SF-36): III. Tests of data quality, scaling assumptions, and reliability across diverse patient groups. Med Care 1994;32:40 – 66. 27. McHorney CA, Ware JE Jr, et al. The MOS 36-Item Short-Form Health Survey (SF-36): II. Psychometric and clinical tests of validity in measuring physical and mental health constructs. Med Care 1993;31:247–263. 28. Ruta DA, Abdalla MI, Garratt AM, et al. SF 36 health survey questionnaire: I. Reliability in two patient based studies. Qual Health Care 1994;3:180 –185. 29. Ware JE Jr. The MOS 36-item short-form health survey (SF-36). Med Care 1992;30:473– 483. 30. Mant JW, Jenkinson C, Murphy MF, et al. Use of the Short Form-36 to detect the influence of upper gastrointestinal disease on self-reported health status. Qual Life Res 1998;7:221–226. 31. Derogatis LR, Covi L. SCL-90: an outpatient psychiatric rating scale—preliminary report. Psychopharmacol Bull 1973;9:13–28. 32. Jones MP, Schettler A, Olden K, et al. Alexithymia and somatosensory amplification in functional dyspepsia. Psychosomatics 2004;45:508 –516. 33. Fischler B, Tack J, De Gucht V, et al. Heterogeneity of symptom pattern, psychosocial factors, and pathophysiological mechanisms in severe functional dyspepsia. Gastroenterology 2003; 124:903–910. 34. Cyr JJ, McKenna-Foley JM, Peacock E. Factor structure of the SCL-90-R: is there one? J Pers Assess 1985;49:571–578. 35. Brophy CJ, Norvell NK, Kiluk DJ. An examination of the factor structure and convergent and discriminant validity of the SCL-90R in an outpatient clinic population. J Pers Assess 1988; 52:334 –340. 36. Rief W, Fichter M. The Symptom Check List SCL-90-R and its ability to discriminate between dysthymia, anxiety disorders, and anorexia nervosa. Psychopathology 1992;25:128 –138. 37. Schmitz N, Kruse J, Heckrath C, et al. Diagnosing mental disorders in primary care: the General Health Questionnaire (GHQ) and the Symptom Check List (SCL-90-R) as screening instruments. Soc Psychiatry Psychiatr Epidemiol 1999;34:360 –366.
Address requests for reprints to: Michael P. Jones, MD, 251 East Huron Street, Galter Pavilion 4-104, Chicago, Illinois 60611-2908. e-mail: [email protected]; fax: (312) 926-6540.
Psychosocial Correlates of Symptoms in Functional Dyspepsia MICHAEL P. JONES,* LISA K. SHARP,‡ and MICHAEL D. CROWELL§ *Division of Gastroenterology, ‡Department of Family Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; and § Division of Gastroenterology, Mayo Clinic, Scottsdale, Arizona
Background & Aims: Psychosocial factors may influence both symptom generation and reporting in functional dyspepsia. We determined the presence and severity of these factors as well as their relationship to dyspeptic symptoms in patients with functional dyspepsia and healthy subjects. Methods: A total of 151 consecutive patients with functional dyspepsia referred chiefly from primary care clinics and 90 healthy subjects rated 15 dyspeptic symptoms. Participants completed the Medical Outcomes Study SF-36 and Symptom Checklist-90 –revised. Results: Functional dyspepsia patients reported significantly higher symptom scores, poorer quality of life, and greater psychiatric distress than healthy subjects. For both patients and healthy subjects, increasing symptom scores were associated with significant decreases in the Physical but not the Mental Components Summary of the Medical Outcomes Study SF-36. Although functional dyspepsia patients showed significantly greater psychiatric distress than healthy subjects, symptoms were correlated only modestly with scores on the Symptom Checklist-90 –revised. A number of symptoms showed significant but modest correlations (rs < .30) with the somatization scale with chest burning correlating most strongly (rs ⴝ .48). Chest burning also was correlated significantly with depression, anxiety, and phobic anxiety. Functional dyspepsia patients at a secondary level of care have greater symptom severity, poorer quality of life, and greater psychiatric distress than healthy subjects. Increasing symptom severity is associated with poorer quality of life primarily in the areas of physical and social functioning. With the exception of chest burning, symptoms are not correlated highly with psychiatric distress. Conclusions: These data suggest that although functional dyspepsia patients experience increased psychiatric distress, symptom severity and psychiatric distress are not associated strongly.
unctional gastrointestinal disorders are medically unexplained symptoms commonly encountered in the general community and associated with reduced quality of life and increased health care resource use and expenses.1– 4 Presently, these disorders appear best explained by a biopsychosocial model of illness; although the exact role of psychosocial factors is not yet clear.5,6
F
Psychosocial factors have been felt to influence digestive symptoms in either 1 of 2 ways. Some investigators have felt that psychosocial factors are causative in symptom generation. The greatest support for this argument comes from studies documenting a high prevalence of comorbid psychiatric diagnoses in patients with functional digestive disorders.7–10 The greatest criticism of this line of reasoning is that the majority of evidence comes from referral populations containing refractory patients predisposed to have a high prevalence of psychiatric illness. The second way in which psychosocial factors influence symptoms in functional gastrointestinal disorders is through enhanced health care seeking. Several studies have shown that compared with dyspeptic nonconsulters, consulters have greater degrees of psychiatric distress, greater somatization, and less-adaptive coping styles.11–15 Psychosocial variables known to influence symptom reporting include coping styles, anxiety, depression, life stress, neuroticism, illness behavior, and somatization.11,12,16 –18 Somatization, in particular, is an extremely relevant variable in symptom provocation studies. Somatization is a complex construct that is defined variably. We use the definition put forth by Lipowski19 because it is used and endorsed widely in the behavioral literature. According to Lipowski,19 somatization is the tendency to express emotional dysphoria as physical symptoms. Although the causes of somatization are multifactorial, an associated psychiatric disorder (often anxiety or depression) is encountered commonly.19,20 Although the role of psychiatric illness in irritable bowel syndrome has been addressed extensively, the literature on psychosocial correlates in functional dyspepsia is not as mature.21 The aim of the present investigation was 2-fold. First, we sought to characterize relevant psychosocial variables and quality of life in a population of patients with functional dyspepsia primarily referred from a primary care clinic as compared with healthy © 2005 by the American Gastroenterological Association
1542-3565/05/$30.00 PII: 10.1053/S1542-3565(05)00245-4
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controls. Second, we sought to correlate these psychosocial variables with specific dyspeptic symptoms. The a priori hypothesis was that if dyspeptic symptoms represented the physical manifestations of various aspects of psychiatric distress (ie, somatization), there should be correlations between specific symptoms, measures of somatization, and specific psychosocial variables.
Materials and Methods Patients with functional dyspepsia were recruited consecutively after being evaluated by the principal investigator (M.P.J.). Ninety percent of these patients either were referred from a primary care physician or were self-referred. The remaining 10% were referred by another gastroenterologist. Two thirds of recruited patients were enrolled. Functional dyspepsia was defined using Rome II criteria for functional dyspepsia (Table 1).22 Patients with functional dyspepsia were categorized further as ulcer-like dyspepsia or dysmotility-like dyspepsia by using Rome II guidelines. Patients were considered to have ulcer-like dyspepsia if the predominant symptom was pain centered in the upper abdomen. Patients were considered to have dysmotility-like dyspepsia if their predominant symptom was a nonpainful sensation characterized or associated with upper-abdominal fullness, early satiety, bloating, or nausea. The predominant symptom was ascertained by direct query regarding the patient’s most bothersome symptom. Patients were excluded if they had dominant complaints of heartburn, prior digestive surgery other than cholecystectomy or appendectomy, or were taking medications known or suspected of altering digestive motility. A patient was considered to have a dominant complaint of heartburn if that patient declared heartburn to be the most bothersome symptom. All patients were required to have a normal upper-gastrointestinal endoscopy with further evaluation performed as indicated by the evaluating gastroenterologist. Healthy patients not receiving care for digestive disorders and not using medications to treat digestive symptoms were recruited as controls by advertisement. Controls also were excluded if they had prior digestive surgery other than cholecystectomy or appendectomy or used medications known commonly to cause adverse digestive symptoms or affect digestive motility. The study was approved by the Institutional Review
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Board of Northwestern University and all patients provided informed consent.
Questionnaires Participants completed several self-report measures pertaining to symptomatology and psychologic traits. Dyspeptic symptoms were evaluated using the symptom assessment portion of the Nepean Dyspepsia Index, which queries symptoms over the 2 weeks before administration.23,24 Fifteen common dyspeptic symptoms were queried specifically by using a Likert scale that evaluated the frequency, intensity, and intrusiveness of each symptom. The scores for frequency, intensity, and intrusiveness were summed to give a score for each symptom that could range from 0 to 13, with higher values representing greater symptom severity. The total symptom score was calculated as the sum of the scores for all individual scores and could range from 0 to 195. The patient’s general quality of life was assessed by using the Medical Outcomes Study SF-36 (SF-36).25–27 The SF-36 is a well-studied, valid instrument that has been used to determine general quality of life in a variety of clinical settings including functional gastrointestinal disorders.27–30 This measure assesses 8 health concepts: (1) limitations in physical activities because of health problems; (2) limitations in social activities because of physical or emotional problems; (3) limitations in usual role activities because of physical health problems; (4) bodily pain; (5) general mental health (psychologic distress and well-being); (6) limitations in usual role activities because of emotional problems; (7) vitality (energy and fatigue); and (8) general health perceptions. Physical and mental composite summaries represent the weighted aggregate scores of relevant scales transformed into t-scores. Lower scores indicate poorer quality of life. Psychiatric distress was measured using the total score of the Symptom Checklist-90 –Revised (SCL-90 –R), which is a selfreport, clinical symptom rating scale consisting of 90 symptoms associated with 9 psychiatric constructs.31 These constructs are somatization, obsessive-compulsive behavior, feelings of inadequacy or inferiority (interpersonal sensitivity), depression, anxiety, hostility, phobic anxiety, paranoid ideation, and psychoticism. The total score for the measure was reported as a raw value whereas the scale scores were converted into t scores by using published values for healthy outpatients.
Table 1. Rome II Diagnostic Criteria for Functional Dyspepsia Including Ulcer-Like and Dysmotility-Like Subgroups At least 12 weeks, which need not be consecutive, within the preceding 12 months of: Persistent or recurrent dyspepsia (pain or discomfort centered in the upper abdomen); and No evidence of organic disease (including at upper endoscopy) that is likely to explain the symptoms; and No evidence that dyspepsia is exclusively relieved by defecation or associated with the onset of a change in stool frequency or stool form (ie, not irritable bowel); and Pain centered in the upper abdomen as the predominant (most bothersome) symptom. NOTE. The following definitions were used: ulcer-like dyspepsia, pain centered in the upper abdomen is the predominant (most bothersome) symptom; dysmotility-like dyspepsia, an unpleasant or troublesome nonpainful sensation (discomfort) centered in the upper abdomen is the predominant symptom; this sensation may be characterized by or associated with upper-abdominal fullness, early satiety, bloating, or nausea. Data from Talley et al.22
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Healthy Subject Characteristics Ninety healthy subjects also completed the surveys. The median age of this group was 36 years (range, 27– 45 y) and the group included 61 women and 29 men. The groups did not differ significantly with respect to age (P ⫽ .80) or sex (P ⫽ .09), although the control group did contain more men. Dyspepsia Symptom Scores
Figure 1. Scores for individual symptom queried by the Nepean Dyspepsia Index. Columns represent median values and error bars represent the interquartile range. Each symptom was rated for its frequency, severity, and bothersomeness. The scores for these 3 symptom characteristics were summed to give a total symptom score that could range from 0 to 13 points.
Statistical Analysis The normality of all datasets was determined using the Kolmogorov–Smirnov test. Because some of the data were not distributed normally, all data were expressed as medians (25th–75th percentile) for purposes of consistency. For normally distributed data, correlations were calculated using the Pearson method and differences between groups were determined using unpaired t tests. Correlations between non–normally distributed or categoric datasets were determined using the Spearman method whereas differences between median group scores were determined using the Mann–Whitney test. Statistical significance was set at P ⬍ .05. Statistical calculations were performed using GraphPad Prism version 3.00 for Windows (GraphPad Software, San Diego, CA).
Results Patient Characteristics A total of 151 patients with functional dyspepsia completed the survey. The median (25th–75th percentile) age was 35 years (range, 27– 46 y) and the group included 118 women and 33 men. Twenty-five patients (17%) had upper-abdominal pain as a dominant symptom and were classified as having ulcer-like dyspepsia. The remaining 126 patients (83%) were classified as having dysmotility-like dyspepsia. Because the number of patients with ulcer-like dyspepsia was small, comparisons were not made between patients with ulcer-like and dysmotility-like dyspepsia. Similarly, comparisons were not made between patients referred from primary care clinics or gastroenterologists or between physician-referred vs self-referred patients because of the small number in the self-referred or gastroenterologist-referred groups.
The median total dyspepsia symptom score was 78 (range, 51–112) for patients with functional dyspepsia and 3 (range, 0 – 6) for controls (P ⬍ .0001). Scores for the 15 queried symptoms in the patients with functional dyspepsia are shown in Figure 1. Although most patients were classified as having dysmotility-like dyspepsia based on dominant symptoms of upper-abdominal discomfort rather than pain, symptom scores for pain and discomfort were correlated highly (rs ⫽ .69; P ⬍ .0001). Quality-of-Life Scores Compared with control patients, quality of life as measured by the SF-36 was diminished in patients with functional dyspepsia (Figure 2). Patients with functional dyspepsia had significantly lower scores on all scales of the SF-36 (P ⬍ .0001 for all). Additionally, both physical and mental component summary scores likewise were reduced. For patients with functional dyspepsia, the median physical component summary score was 36 (range, 25– 49) and the median mental component summary score was 33 (range, 25– 42). This was significantly lower than the control group in which the median physical component summary score was 58 (range, 57–59) and the median mental component summary score was 47 (range, 43–50) (P ⬍ .0001 for both). Psychiatric Distress Patients with functional dyspepsia endorsed responses on the SCL-90 –R indicating increased levels of
Figure 2. Quality of life as measured by the SF-36. Patients with functional dyspepsia () had significantly lower scores (P ⬍ .0001) on all scales of the SF-36 compared with healthy patients (□). Columns represent median values and error bars reflect the interquartile range. PF, physical functioning; RP, role-physical; BP, bodily pain; SF, social functioning; MH, mental health; RE, role-emotional; VT, vitality; GH, general health.
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Figure 3. SCL-90 –R scores for healthy patients and patients with functional dyspepsia. The t-scores for patients with dyspepsia () differed significantly (P ⬍ .0001) from those of healthy patients (□) on all scales. Columns represent median values, and error bars are the interquartile range. Obs-compuls, obsessive-compulsive; inter. sens., interpersonal sensitivity. phob. anxiety, phobic anxiety; para. ideation, paranoid ideation.
psychiatric distress. The median total score for patients with dyspepsia was 53 (30 – 89) compared with 9 (4 –20) for healthy patients (P ⬍ .0001). The t-scores for each of the 8 scales are shown in Figure 3. Compared with healthy patients, the patients with functional dyspepsia scored significantly higher (P ⬍ .0001) on all SCL-90 –R scales. Association of Dyspeptic Symptoms and Quality of Life For patients with functional dyspepsia, the total dyspeptic symptom score significantly correlated with the SF-36 physical component summary score (rs ⫽ ⫺.46; P ⬍ .0001) but not with the mental component summary score (rs ⫽ .12; P ⫽ .23). For healthy patients, no significant correlations existed with either the physical component summary score (rs ⫽ ⫺.24; P ⫽ .13) or the mental component summary score (rs ⫽ ⫺.16; P ⫽ .33). Among patients with dyspepsia, significant correlations existed with individual scale scores for bodily pain (rs ⫽ ⫺.51; P ⬍ .0001), physical functioning (rs ⫽ ⫺.41; P ⬍ .0001), social functioning (rs ⫽ ⫺.37; P ⬍ .0001), vitality (rs ⫽ ⫺.27; P ⫽ .0045), and physical role (rs ⫽ ⫺.25; P ⫽ .009). No significant correlations existed between the total dyspeptic symptom score and scores on the general health, mental health, and emotional role scales. Association of Dyspeptic Symptoms and Psychiatric Distress Patients with functional dyspepsia displayed a modest but significant correlation between the dyspeptic symptom score and the total score on the SCL-90 –R (rs ⫽ .24; P ⫽ .0117). Among patients with dyspepsia, we sought to determine whether the correlations between total dyspeptic symptom scores and psychiatric distress might be greater in patients with more severe psychiatric distress. The
lower and upper tertiles for the SCL-90 –R total scores were analyzed separately. The Spearman correlations between the total dyspeptic symptom score and SCL-90 –R scores in the lower tertile and upper tertile were .28 (P ⫽ .29) and .25 (P ⫽ .376). Total dyspeptic symptom scores were higher for the upper tertile group (95; range, 64 – 114) than for the lower tertile group (73; 40 –98) but these differences did not achieve statistical significance (P ⫽ .1). Among patients with dyspepsia, the strongest correlation between dyspeptic symptom scores and SCL-90 –R scale scores existed with somatization (rs ⫽ .51; P ⬍ .0001). Modest but significant correlations also existed with the phobic anxiety (rs ⫽ .22; P ⫽ .0199) and anxiety scales (rs ⫽ .20; P ⫽ .035). Association of Specific Dyspeptic Symptoms With Quality of Life and Psychiatric Distress For patients with functional dyspepsia, the relationships between specific dyspeptic symptoms, total SCL-90 –R score, SCL-90 –R scale scores, and SF-36 scores also were explored. In this analysis only data from subjects endorsing a specific symptom were included to identify how endorsing a symptom differentially impacted quality of life. The relationship between specific dyspeptic symptoms and SF-36 scores is shown in Table 2. In general, symptoms were associated with decrements in the physical rather than mental aspects of quality of life. Ten of 15 symptoms had significant modest inverse correlations with the bodily pain scale of the SF-36. Seven of 15 symptoms also had significant modest inverse correlations with the social functioning scale. Eight of 15 symptoms showed significant correlations with summary component scores, and 7 of 8 of these symptoms were correlated significantly with the physical component summary score. Only chest burning was correlated sig-
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nificantly with the mental component summary score, which largely was attributable to its significant inverse correlations with mental health, emotional role, and vitality in addition to a positive correlation with abdominal pain. The association of chest burning with decrements in the emotional aspects of quality of life is supported by significant correlations of symptom scores for chest burning with the total SCL-90 –R score as well as scale scores for somatization, depression, anxiety, phobic anxiety, and psychoticism (Table 3). Although 6 other symptoms had significant correlations with somatization, there were few other significant correlations with any other subscale scores and none explained more than 15% of the variance. Although correlations of symptoms with somatization were the strongest correlations seen with the SCL90 –R scales, these correlations were modest and explained only 7%–23% of the variance.
Discussion Compared with healthy patients, the patients with functional dyspepsia had significantly greater scores for dyspeptic symptoms, significantly greater psychiatric distress as measured by the SCL-90 –R, and significantly poorer quality of life as measured by the SF-36. Overall, symptom severity as measured by both scores for individual symptoms or the total dyspepsia symptom score correlated poorly with both the total score and scale scores on the SCL-90 –R. The symptom of chest burning was the greatest exception to this finding. Forty-five patients (30% of our sample) acknowledged this symptom. Of the 15 dyspeptic symptoms queried, this symptom was the most highly correlated with the total SCL90 –R score (rs ⫽ .44; P ⫽ .001) and was also the symptom most highly correlated with the scale scores for somatization, depression, anxiety, phobic anxiety, and psychoticism. Importantly, chest burning was also the only symptom significantly correlated with impairments in the mental component summary of the SF-36 (rs ⫽ ⫺.47; P ⬍ .001). The lack of an association between psychiatric distress and symptom severity (with the exception of burning chest pain) argues against a role for somatization as defined by Lipowski19 and others.20 Although several symptoms had modest, statistically significant associations with the somatization scale of the SCL-90 –R, it should be pointed out that 3 of the 12 items on the somatization scale pertain to digestive function. These include pain in the heart or chest, nausea or upset stomach, and lump in your throat. Because of this, the somatization scale of the SCL-90 –R may tend to over-
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estimate the role of somatization in patients with digestive disorders. We purposely did not remove these items from the survey because we did not wish to compromise the structure of the instrument. We recently have published data showing that in patients with functional dyspepsia, there is a statistically significant but clinically modest increase in scores for somatosensory amplification.32 Thus, although somatization is clearly a cause of symptoms in some patients with functional digestive disorders, it is not a dominant mechanism across a population of patients with dyspeptic symptoms. Dyspeptic symptom severity most strongly correlated with changes on the physical component summary of the SF-36. The most profound differences with respect to quality of life exist in elements associated with physical role and social functioning. The exception to this, as previously mentioned, was burning chest pain that was not correlated with the physical component summary (rs ⫽ ⫺.10; P ⫽ .50) but was significantly correlated with the mental component summary (rs ⫽ ⫺.47; P ⬍ .0001). If psychiatric distress was associated more strongly with dyspeptic symptoms, we would have expected greater associations between symptom scores and factors associated with the mental component summary of the SF-36. This study has evaluated associations between reported dyspeptic symptom severity, quality of life, and psychiatric distress. It cannot define mechanistic relationships between these variables and caution is necessary in interpreting the absence of a relationship between psychiatric distress and dyspeptic symptoms because a type II error is possible. However, the fact that we did confirm the often-reported association of chest pain and psychiatric distress makes a type II error less likely. Additionally, functional dyspepsia is not a homogenous disorder and it is likely that there are subgroups of patients with functional dyspepsia having different symptom causes.33 Our methods of assessment did not allow us to address this and a substantially larger sample size would be needed to use factor analysis using these measures. The present study had several limitations. Patients were recruited from a single clinic and recruitment was consecutive but enrollment was not. Patients not wishing to participate may have differed from those choosing to complete the surveys. We did not pursue a formal psychiatric evaluation or detailed psychiatric history in our patients. Formal diagnostic interviews for psychopathology, particularly somatoform disorders, would have added useful information that might have influenced the interpretation of our data. Additionally, we did not assess
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Table 2. Correlation of Specific Dyspeptic Symptoms With Alterations in Quality of Life Symptom (n)
PCS
MCS
PF
RP
Pain in upper abdomen (81) Discomfort in upper abdomen (88) Burning in upper abdomen (45) Chest burning (49) Cramps (44) Chest pain (42) Inability to finish meal (82) Regurgitation (62) Fullness/slow digestion (99) Pressure in upper abdomen (62) Bloating in upper abdomen (79) Nausea (91) Burping/belching (81) Vomiting (55) Bad breath (47)
⫺.44 (⬍.001) ⫺.38 (⬍.001) ⫺.24 (.11) ⫺.10 (.50) ⫺.32 (.03) ⫺.14 (.39) ⫺.30 (.007) ⫺.17 (.20) ⫺.26 (.01) ⫺.19 (.14) .08 (.51) ⫺.30 (.004) ⫺.14 (.20) ⫺.30 (.02) ⫺.23 (.13)
⫺.06 (.61) ⫺.003 (.98) ⫺.11 (.48) ⫺.47 (⬍.001) .26 (.08) ⫺.16 (.30) .11 (.31) ⫺.03 (.80) .10 (.30) ⫺.01 (.94) .14 (.20) .10 (.35) .06 (.61) .16 (.24) ⫺.23 (.12)
⫺.37 (⬍.001) ⫺.22 (.04) ⫺.053 (.73) .074 (.62) ⫺.26 (.09) ⫺.07 (.66) ⫺.20 (.07) ⫺.14 (.28) ⫺.28 (.01) ⫺.18 (.17) .04 (.72) ⫺.22 (.03) ⫺.10 (.36) .32 (.02) ⫺.10 (.51)
⫺.32 (.003) ⫺.26 (.013) ⫺.13 (.41) ⫺.16 (.27) ⫺.16 (.28) ⫺.05 (.75) ⫺.15 (.18) ⫺.09 (.51) ⫺.12 (.23) ⫺.10 (.43) .08 (.46) ⫺.21 (.05) ⫺.04 (.70) .001 (.99) ⫺.31 (.03)
NOTE. Increasing symptom severity generally is associated with decreases in physical composite summary scores largely attributable to decreases in bodily pain scores. A notable exception is chest burning, which is associated primarily with significant reductions in mental composite summary scores. Data are expressed as rs (p). PCS, physical component summary; MCS, mental component summary; PF, physical functioning; RP, role-physical; BP, bodily pain; GH, general health; SF, social functioning; MH, mental health; RE, role-emotional; VT, vitality.
extraintestinal symptoms. Patients with somatized distress often have increased extraintestinal as well as evolving or migrating pains. Assessing for extraintestinal symptoms would have strengthened our assessment. Although we chose the survey instruments used because they are valid, reproducible measures that have been used widely in a variety of clinical scenarios including functional digestive disorders, they do have limitations. It has been questioned whether the use of the SCL-90 –R may be limited beyond being a measure of general psychiatric distress.34,35 A number of other studies, however, have supported the validity of the SCL90 –R scales.36,37 Because of these concerns, we have
limited our interpretations to those based on the relationships between the total SCL-90 –R score and symptoms and have included scale scores and relationships in the results for completeness. This study should not be construed as an attempt to create an SCL-90 –R profile for patients with functional dyspepsia. Finally, it could be argued that functional dyspepsia simply represents a chronic pain syndrome and that because the SF-36 and SCL-90 –R contain questions relating to pain, these measures would produce a biased response. However, the study population was comprised primarily of patients with motility-like dyspepsia and, as is shown in Figure 1, pain was only the fifth highest
Table 3. Correlation of Specific Dyspeptic Symptoms With SCL-90 –R Scale Scores Symptom (n)
Total score
Somatization
Obsessivecompulsive
Interpers sensitivity
Pain in upper abdomen (75) Discomfort in upper abdomen (82) Burning in upper abdomen (40) Chest burning (45) Cramps (39) Chest pain (38) Inability to finish meal (77) Regurgitation (57) Fullness/slow digestion (92) Pressure in upper abdomen (58) Bloating in upper abdomen (75) Nausea (85) Burping/belching (76) Vomiting (52) Bad breath (32)
.21 (.05) .23 (.03) .34 (.02) .47 (.001) ⫺.12 (.45) .26 (.10) ⫺.04 (.73) .29 (.02) .20 (.04) .17 (.17) .07 (.53) .02 (.89) .13 (.24) .01 (.99) .27 (.06)
.28 (.02) .25 (.02) .28 (.08) .48 (⬍.001) .15 (.36) .41 (.01) .17 (.14) .27 (.04) .30 (.003) .28 (.03) ⫺.03 (.81) .16 (.15) .22 (.05) .17 (.22) ⫺.04 (.79)
.07 (.54) .09 (.41) .17 (.30) .10 (.52) ⫺.11 (.52) .07 (.68) ⫺.08 (.47) .01 (.92) .01 (.92) .12 (.37) ⫺.22 (.06) ⫺.05 (.64) .002 (.98) ⫺.09 (.52) .10 (.51)
⫺.01 (.94) .01 (.94) .13 (.43) .21 (.17) ⫺.14 (.39) .10 (.56) ⫺.05 (.67) .03 (.81) .03 (.79) .05 (.73) ⫺.03 (.80) ⫺.23 (.03) ⫺.12 (.29) ⫺.17 (.23) ⫺.02 (.88)
NOTE. Increasing symptom severity is significantly but modestly associated with somatization. Only chest burning has significant scale associations. Severity scores for other symptoms are not significantly correlated with measures of psychiatric distress. Data are expressed as rs (P).
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Table 2. (continued) BP
GH
SF
MH
RE
VT
⫺.41 (⬍.001) ⫺.40 (⬍.001) ⫺.34 (.02) ⫺.34 (.02) ⫺.31 (.04) ⫺.32 (.04) ⫺.31 (.01) ⫺.20 (.12) ⫺.36 (⬍.001) ⫺.21 (.11) .10 (.37) ⫺.29 (.005) ⫺.15 (.17) ⫺.31 (.02) ⫺.29 (.05)
⫺.18 (.12) ⫺.04 (.75) .03 (.83) ⫺.37 (.008) ⫺.02 (.89) ⫺.10 (.53) .04 (.72) ⫺.04 (.74) ⫺.06 (.54) ⫺.04 (.77) .02 (.83) ⫺.04 (.68) .04 (.70) ⫺.03 (.84) ⫺.13 (.38)
⫺.39 (⬍.001) ⫺.40 (⬍.001) ⫺.25 (.09) ⫺.24 (.10) ⫺.16 (.30) ⫺.03 (.83) ⫺.23 (.04) ⫺.22 (.08) ⫺.21 (.04) ⫺.17 (.19) .06 (.59) ⫺.40 (⬍.001) ⫺.18 (.11) ⫺.34 (.01) ⫺.25 (.09)
⫺.10 (.36) ⫺.14 (.20) ⫺.23 (.14) ⫺.34 (.02) .07 (.67) ⫺.15 (.35) .08 (.47) ⫺.18 (.17) .03 (.79) ⫺.09 (.46) .06 (.62) .07 (.52) .01 (.95) .04 (.78) ⫺.29 (.046)
⫺.16 (.15) ⫺.12 (.27) ⫺.11 (.47) ⫺.29 (.04) .21 (.16) ⫺.22 (.17) .06 (.57) ⫺.18 (.15) .04 (.67) ⫺.06 (.63) .23 (.046) .01 (.90) .03 (.79) .04 (.78) ⫺.20 (.19)
⫺.23 (.04) ⫺.14 (.19) ⫺.24 (.12) ⫺.43 (.002) .025 (.87) ⫺.14 (.37) ⫺.16 (.15) ⫺.04 (.77) ⫺.14 (.18) ⫺.10 (.46) .10 (.38) .10 (.35) ⫺.08 (.48) ⫺.01 (.94) ⫺.35 (.02)
scoring symptom. Although there may be limitations to the use of the SF-36 and SCL-90 –R in patients with dominant complaints of chronic pain, the majority of patients with motility-like dyspepsia do not endorse symptoms of abdominal pain. In summary, the current study shows that patients with functional dyspepsia at a secondary level of care have both enhanced symptomatology and psychiatric distress but that the 2 generally are not correlated. The exception to this observation appears to be the symptom of chest burning with anxiety and phobic anxiety. The impact of symptomatology is seen most profoundly on the physical and social aspects of functioning without
much disturbance in mental or emotional aspects. The findings of this study should be of particular relevance to both primary care physicians and gastroenterologists in community practice because the vast majority of these patients came from primary care clinics and were not seen previously by a gastroenterologist. This is a level of care underinvestigated in the clinical investigation of functional digestive disorders in general and functional dyspepsia in particular. These data suggest that digestive symptoms at this level of care are unlikely to represent physically manifested emotional distress. It also seems unlikely that emotional distress is a consequence of dyspeptic symptoms. Rather, it seems that dyspeptic symp-
Table 3. (continued) Depression
Anxiety
Anger-hostility
Phobic anxiety
Paranoid ideation
Psychoticism
.22 (.06) .23 (.04) .29 (.07) .34 (.02) ⫺.11 (.50) .21 (.20) .06 (.60) .18 (.19) .09 (.39) .15 (.26) ⫺.06 (.60) ⫺.05 (.68) ⫺.07 (.56) ⫺.18 (.20) .10 (.51)
.15 (.20) .14 (.21) .38 (.02) .39 (.01) .04 (.80) .25 (.14) ⫺.05 (.67) .13 (.32) .09 (.40) .22 (.09) ⫺.10 (.37) .06 (.61) .01 (.93) .05 (.71) .27 (.08)
⫺.01 (.91) .02 (.84) .10 (.56) .19 (.21) ⫺.15 (.36) .06 (.74) ⫺.06 (.61) ⫺.04 (.78) ⫺.02 (.84) .06 (.64) ⫺.08 (.47) ⫺.13 (.23) .01 (.93) .06 (.70) .11 (.47)
.24 (.04) .25 (.03) .23 (.16) .32 (.03) ⫺.002 (.99) .18 (.29) .07 (.53) .16 (.24) .15 (.16) .21 (.12) .03 (.81) .08 (.47) .07 (.53) .09 (.52) .19 (.22)
⫺.02 (.85) ⫺.03 (.82) .09 (.57) .26 (.08) ⫺.25 (.12) .25 (.13) .04 (.71) .07 (.62) ⫺.01 (.92) .004 (.97) ⫺.10 (.39) ⫺.28 (.01) ⫺.12 (.30) ⫺.06 (.67) .12 (.45)
.10 (.38) .16 (.16) .29 (.07) .32 (.03) ⫺.09 (.58) .21 (.20) .01 (.96) .10 (.48) .04 (.73) .07 (.59) ⫺.12 (.30) ⫺.01 (.93) ⫺.03 (.83) ⫺.002 (.99) .22 (.16)
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toms in this population are occurring against a background of concomitant psychiatric distress.
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Address requests for reprints to: Michael P. Jones, MD, 251 East Huron Street, Galter Pavilion 4-104, Chicago, Illinois 60611-2908. e-mail: [email protected]; fax: (312) 926-6540.