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A short-form questionnaire identified genital organ prolapse
Journal of Clinical Epidemiology 58 (2005) 41–46
A short-form questionnaire identified genital organ prolapse Gunilla Tegerstedta,b,c,*, Ann Miedela,c, Marianne Maehle-Schmidtb, Olof Nyrenb,c, Margareta Hammarstro¨ma,c,d a
Department of Obstetrics and Gynaecology, Karolinska Institutet, Stockholm So¨der Hospital, Stockholm S-118 83, Sweden b Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm S-118 83, Sweden c Clinical Epidemiology Unit, Department KI, So¨der Hospital, Stockholm S-118 83, Sweden d Octaviakliniken, Tideliusgatan 22, 11869 Stockholm Accepted 9 June 2004
Abstract Objective: We constructed a simple questionnaire that, with a minimum of questions, could accurately and reliably identify women with genital organ prolapse. Study Design and Setting: Two hundred women with confirmed genital organ prolapse and 199 outpatients with various gynecologic symptoms but no objective prolapse answered 13 questions perceived to be valuable for the diagnosis. With stepwise backward logistic regression, the discriminatory ability of a successively abbreviated set of questions was assessed. The resulting short questionnaire was tested in a new population-based sample of 282 women participating in a screening survey. Results: A final five-item questionnaire retained 94% of the predictive value of all 13 questions and had 92.5% sensitivity and 94.5% specificity in the first group of women. When the questionnaire was used in the subsequent population-based survey, the sensitivity and specificity values were 66.5% and 94.2%, respectively. Most missed cases had stage I prolapse. Conclusion: Although the sensitivity of the test was moderate, the specificity, and hence the ability to rule in cases, was satisfactory. The test is suitable for case finding in epidemiologic studies. 쑖 2005 Elsevier Inc. All rights reserved. Keywords: Questionnaire; Genital organ prolapse; Validation; Prolapse-related symptoms
1. Introduction The common patient history remains a cornerstone in everyday practice, yet its diagnostic performance is essentially unexplored for many common conditions. Which questions need to be asked, and at which point do additional questions become superfluous? The concern about redundant data collection is particularly justifiable in epidemiologic studies, where unnecessarily long questionnaires may hamper response rates. Symptoms of pelvic floor disorders in women are a common cause for medical contacts. Estimations of prevalence of genital organ prolapse reported in the literature range from 4.4% to 50% [1–4]. This vast variation suggests that definitions and epidemiologic methodologies may require careful consideration. Valid and reliable data on the true prevalence is important for the planning of health care for
* Corresponding author. Department of Obstetrics and Gynaecology, Karolinska Institutet, Stockholm So¨der Hospital, Stockholm S-118 83, Sweden. Tel.: ⫹44 8 616 26 46; fax: ⫹44 8 616 43 93. E-mail address: [email protected] (G. Tegerstedt). 0895-4356/04/$ – see front matter 쑖 2005 Elsevier Inc. All rights reserved. doi: 10.1016/j.jclinepi.2004.06.008
women and for putting the clinical finding of genital organ prolapse in an individual patient into perspective. The aim with this study was to construct a short questionnaire that, with a minimum of questions, retained the ability to discriminate between women with and without genital organ prolapse. 2. Methods 2.1. Phase 1: Development of the questionnaire We compiled 13 questions perceived to be valuable for the diagnosis and therefore often used in medical history taking (Table 1). To evaluate the sensitivity of these questions, alone or in various combinations, they were administered to 200 women with confirmed genital organ prolapse attending the outpatient clinic for symptoms or being on the waiting list for surgery. All women were routinely examined by a gynecologist at the Department of Obstetrics and Gynecology, Stockholm So¨der Hospital, using the Becham classification [5]. All had second- or third-degree prolapse, which means that the prolapse had reached the introitus or beneath.
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G. Tegerstedt et al. / Journal of Clinical Epidemiology 58 (2005) 41–46
Table 1 The 13 questions used in the first part of the investigation Question 1. 2. 3. 4.
Do you have a sensation of vaginal heaviness or pressure? Do you have a sensation of tissue protrusion (vaginal bulge) from vagina? Do you suffer from scraping in your vagina/vulva? Has a doctor, in connection with a gynecologic examination, told you that you have a genital organ prolapse? 5. If you have symptoms, are they different during the day? 6. Are your symptoms worse during stress, for example, during heavy lifting? 7. Do you have difficulties emptying your bladder? 8. Do you have difficulties emptying your bowels? 9. Do you have to lift the anterior vaginal wall to start or complete voiding? 10. Do you have to do a digital manipulation of the vagina, perineum, or anus to complete voiding? 11. Do you suddenly feel the urge to go to the toilet, and then accidentally leak urine? 12. Do you leak urine during coughing, sneezing, or heavy lifting? 13. Do you believe that you have genital organ prolapse?
The specificity was evaluated in another 199 women coming to the outpatient clinic for various gynecologic problems (e.g., dysfunctional bleedings, menopausal symptoms, or cervical dysplasia) but in whom genital organ prolapse was excluded by one of the gynecologists in the research team. The pelvic floor anatomy was defined in conformity with standards recommended by the International Continence Society, the pelvic organ prolapse quantification system (POPQ) [6]. Only women with no demonstrable prolapse (stage 0) were accepted in this group. To assess reproducibility of the answers, 100 women from each group were given the same questions a second time 1 month later.
A
B
C
D
Yes, often Yes, often Yes, often Yes
Sometimes Sometimes Sometimes No
Infrequently Infrequently Infrequently I don’t know
No, ever No, ever No, ever
Worse morning Unchanged Yes, often Yes, often Yes, often Yes, often
Worse day Better Sometimes Sometimes Sometimes Sometimes
Worse dinner Worse Infrequently Infrequently Infrequently Infrequently
Worse evening No, ever No, ever No, ever No, ever No, ever
Yes, often Yes, often Yes
Sometimes Sometimes No
Infrequently Infrequently I don’t know
No, ever No, ever
The most powerful short set of questions (see STATISTICAL was sent to a random sample (n ⫽ 8,000) of the Stockholm female population 29–79 years of age. The response rate was 69%. Among women whose scores were indicative of symptomatic genital organ prolapse, we randomly selected 206 who were invited to a standardized gynecologic examination following the principles of the POPQ. We randomly selected 206 women whose answers indicated absence of genital organ prolapse. The participation in this second phase of the investigation was 79% (n ⫽ 162) and 58% (n ⫽ 120), respectively, among those with and without a positive questionnaire result. Only complete absence of prolapse (stage 0) was defined as nonprolapse. Stages I through IV were defined as prolapse in accordance with the recommended standard terminology for research of pelvic support defects [7].
questions. The cutpoints for positive response to each question were based on visual inspection of response distributions and on prior clinical experience. To select a minimal set of questions that best distinguished between prolapse and nonprolapse women, the following strategy was adopted: We evaluated the diagnostic value of each question in univariate logistic regression models. Then various combinations of the questions were evaluated in multivariate logistic regression models using stepwise backward elimination to arrive at a preliminary multivariate model. The stepwise approach was assumed to work well because there were few missing values in the data. We adjusted for age in all multivariate logistic regression models. The effect of collapsing or extending the number of categories for the questions was evaluated in the resulting preliminary multivariate model. To ensure selection of the most powerful combinations of questions, we evaluated the effect of each of the previously eliminated variables in the new preliminary multivariate model before the final model was chosen. Adjusted odds ratio (OR) scores from the final logistic regression model were tested in discriminant analyses for the development of a discriminant criterion according to which the participating women in the Stockholm sample were classified. We calculated positive and negative predictive values (NPVs) in our studied population sample, emphasizing that these values are dependent on the prevalence of prolapse among the individuals being investigated. Kappa scores evaluated reproducibility. For questions 4, 5, 6, and 11, simple kappa scores were calculated. We used weighted scores for all other questions [9]. This study was approved by the Local Ethics Committee at Karolinska Institutet.
2.3. Statistical methods
3. Results
2.2. Phase II: Testing the questionnaire in an independent sample METHODS)
In the groups of 200 and 199 women with confirmed presence or absence, respectively, of genital prolapse, we calculated crude sensitivity and specificity values with 95% confidence intervals (CI) [8] for each of the 13 original
3.1. Phase 1: Development of a questionnaire The mean age among subjects with pelvic organ prolapse (68 years, median 66.7, range 32–92) was higher than in
G. Tegerstedt et al. / Journal of Clinical Epidemiology 58 (2005) 41–46
the group without (52 years, median 52, range 33–80). The crude sensitivity and specificity values and the reproducibility for each of the 13 questions in the first round are shown in Table 2. The cutpoints used for a positive prolapse categorization are given in the Table 2. The sensitivity ranged from 21% (question 10 “Do you have to do a digital manipulation of the vagina, perineum, or anus to complete voiding?”) to 89% (question 4 “Has a doctor, in connection with a gynecologic examination, told you that you have a genital organ prolapse?”). The specificity ranged from 71% (question 12 “Do you leak urine during coughing, sneezing, or heavy lifting?”) to 98% (question 13 “Do you believe that you have genital organ prolapse?” and question 9 “Do you have to lift the anterior vaginal wall to start or complete voiding?”). The sensitivity of question 13 was artificially high because most of the women with prolapse were already informed about the condition for which they were on the surgical waiting list. The kappa values ranged from 0.61 (question 5 “If you have symptoms, are they different during the day?”) to 0.94 (question 4), and the majority of questions had kappa values exceeding 0.8, indicating almost perfect agreement between answers given 1 month apart. When combining both groups of patients to estimate the importance of each question and its ability to add to the overall
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predictive ability, the resulting logistic regression model after stepwise elimination of redundant questions consisted of questions 2, 6, 9, and 11 together with age that was forced into the model. The OR scores from this logistic regression model were passed to the discriminant analysis. Then scores were adjusted, and question 3 was added to slightly improve the discrimination results. The final model scores are given in Table 3, and the result from the discriminant analysis is given in Table 4. We defined the cut-off value for prolapse at 30 points. Scores higher than 30 represent a positive response for prolapse (Table 4). Questions 2 and 9 carried almost all of the discriminative ability of the test; a model including only age and these two questions performed almost as well as the model including all six pieces of information. A cross-tabulation of test result based on questions 2, 3, 6, 9, and 11 by true diseased status resulted in a sensitivity and specificity of 92.5% and 94.5%, respectively. The positive predictive value (PPV) in this rather artificial mix of prolapse-positive and prolapse-negative women was 94.4%, and the NPV was 92.6%. 3.2. Phase 2: Test of the questionnaire in an independent sample Of 8,000 short-form questionnaires sent out to women living in Stockholm, 5,501 were returned with complete
Table 2 Responses to questionnaire Question about 1 Vaginal heaviness/pressure
Groupa A (%)
1 2 2 Tissue protrusion/vaginal bulge 1 2 3 Vaginal pain/comfort 1 2 4 Knowledge about prolapse 1 2 5 Variation of symptom during day 1 2 6 Heavy lift 1 2 7 Voiding difficulty 1 2 8 Difficulty with defecation 1 2 9 Manual reduction of anterior wall 1 2 10 Digital manipulation to 1 complete defecation 2 11 Urge incontinence 1 2 12 Stress incontinence 1 2 13 Do you imagine that you have 1 a genital organ prolapse? 2 a b
98 9 122 0 35 7 178 10 16 3 43 40 45 4 42 15 16 1 21
(49) (4.5) (61)
3 49 7 60 18 189
B (%)
C (%)
D (%)
(14.5) A ⫹ B versus C ⫹ D (68) 76% (69–81) 89% (83–93) (8) A ⫹ B versus C ⫹ D (91) 86% (80–90) 98% (94–99) (41.5) A ⫹ B versus C ⫹ D (82) 43% (36–49) 98% (94–99) A versus B ⫹ C 89% (84–93) 95% (91–97) (23) B ⫹ D versus A (4.5) 89% (83–93) 13% (5–32) C versus A ⫹ B 76% (69–81) 70% (57–81) (29) A ⫹ B versus C ⫹ D (70) 49% (42–56) 91% (87–95) (36.5) A ⫹ B versus C ⫹ D (51) 44% (37–51) 77% (71–83) (70.5) A ⫹ B ⫹ C versus D (97.5) 28% (22–35) 99% (96–100) (64.5) A ⫹ B versus C ⫹ D
(17.5) (3.5) (89) (5) (8) (1.5) (21.5) (20) (22.5) (2.3) (21) (7.5) (8) (0.5) (10.5)
53 13 49 5 50 9 19 184 32 5 3 0 53 13 46 30 20 0 20
(27) (6.5) (25) (2.5) (25) (4.5) (9.5) (92) (16) (2.5) (1.5)
20 42 13 12 32 17 3 5 52 6 143 17 (26.5) 44 (6.5) 38 (23) 41 (15) 52 (10) 19 2 (10) 27
(10) (21) (6.5) (6) (16) (8.5) (1.5) (2.5) (26.6) (3) (71.5) (8.5) (22) (19) (20.5) (26) (9.5) (1) (13.5)
(1.5) (24.5) (3.5) (30) (9) (95)
9 56 36 47 40 2
(4.5) (28) (18) (23.5) (20) (1)
(6) 175 (87.5) 21% (16–27) 94% (90–97) (30.5) 34 (17) A ⫹ B versus C ⫹ D (40.7) 75 (37.6) 53% (46–59) 78% (72–84) (23) 47 (23.5) A ⫹ B versus C ⫹ D (44.2) 53 (26.6) 54% (47–60) 71% (64–77) (4.5) A versus B ⫹ C
3 (1.5)
162 (82)
12 61 81 46 88 9
34 (17)
29 135 16 182 83 164
Specificityb Sensitivityb (95% CI) (95% CI)
46 9
58 140 71 102 141 195 129
95% (90–97)
Group 1, subjects with genital organ prolapse, n ⫽ 200; group 2, subjects without any prolapse, n ⫽ 199. Sensitivity and specificity are tested in different alternative of answers.
Kappa value 0.84 (0.78–0.89) 0.89 (0.85–0.93) 0.72 (0.64–0.79) 0.94 (0.89–0.99) 0.61 (0.46–0.75) 0.55 (0.40–0.69) 0.82 (0.76–0.87) 0.76 (0.69–0.82) 0.83 (0.73–0.93)
0.76 (0.69–0.83) 0.76 (0.69–0.83) 0.81 (0.75–0.86)
99% (96–100) 0.90 (0.89–0.99)
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Table 3 The final models score. Adjusted odds ratio scores from the final questionnaire
Table 5 Discrimination analyses for sensitivity and specificity for questions 2, 3, 6, 9, 11 in part two, the screening study
Question about
Answer
Score
Age
⬍50 ⬎70 50 ⬍ age ⬍ 70 Yes, often Sometimes/infrequently Never Yes, often Sometimes/infrequently Never Worse Unchanged/better Yes, often/sometimes/ infrequently Never Yes, often Sometimes/infrequently Never
0.2 3 1 50 30 1 5 0.2 1 10 1 11
2. Tissue protrusion/vaginal bulge
3. Vaginal pain/discomfort
6. Heavy lifting 9. Manual reduction of anterior wall 11. Urge incontinence
1 5 0.7 1
answers. The age information from the women was compared with the age information from SPAR, a continuously updated population register. Eleven of the women who answered the questionnaire were eliminated from the analyses because of inconsistencies in age information, leaving a total of 5,490 women in the study population. Every woman was classified through applying the scores derived from the first part of the study. Of the 5,490 women, 454 were classified as having genital organ prolapse with symptoms classified as having no genital organ prolapse. Forty-eight women could not be classified due to missing answers to one or more of the symptom questions. Among the 454 women classified as having genital organ prolapse, 206 were randomly sampled for clinical investigation. Another random sample of 206 women whose scores indicated absence of genital organ prolapse was invited. Two hundred eighty-two of the sampled women came to the examination (68%; Table 6). In Group A (women with prolapse according to the questionnaire), 162 women (79%) participated, and in Group B (women classified by the questionnaire as having no prolapse) 120 (58%) showed up. The POPQ prolapse stages in Group A were as follows: stage 0, 1.9%; stage I, 24.1%; stage II, 59.3%; stage III, 11.7%, and stage IV, 3.1%. In Group B, stage 0 was observed in 33.3%,
a b c
19 11 30
32 6 38
Scores ⬎30, positive response for prolapse. Group 1: 200 women with prolapse. Group 2: 199 women without prolapse.
24 1 25
Stage I–IV
Stage 0
Total
159 80 239
3 40 43
162 120 282
Subjects defined as symptomatic prolapse (group A, n ⫽ 162) or symptomless group B, n ⫽ 120) and examined with pelvic organ prolapse quantification system stage I–IV classified as prolapse (stage 0, absent of prolapse). Sensitivity: 66.5% (95% CI 60.3–72.2) Specificity: 94.2% (95% CI 84.4–98.0.6) Positive predictive value: 98.1% (95% CI 94.7–99.4) Negative predictive value: 38.0% (95% CI 30.1.8–46.6)
stage I in 48.3%, stage II in 17.5%, and stage III in 0.8%. No one in this group had stage IV prolapse. A cross-tabulation (Table 5) reveals that our short-form questionnaire, consisting of only five questions, had a sensitivity of 66.5%, a specificity of 94.2%, a PPV of 98.1%, and a NPV of 38.0% in the population-based survey. Of the false-negative cases (58/80), 72.5% had stage I prolapse, the clinical significance of which is often doubtful. Had we defined symptomatic prolapse as stage II or higher according to POPQ, the sensitivity of our questionnaire would increase to 84.5% (95% CI 77.7–89.5), and the specificity would have dropped to 70.0% (95% CI 62.0–77.0). The corresponding positive and negative values would be 74.1% and 81.7% (Table 4). 4. Discussion We aimed to construct a questionnaire that, with a minimal number of questions, could accurately and reliably identify women with true genital organ prolapse. Five questions, supplemented with information about age, provided essentially all of the discriminatory power of an original set of 13 questions. The sensitivity and specificity were 92.5% and 94.5%, respectively, in the original patient population. In a subsequent population-based survey, the sensitivity was lower (66.5%), whereas the specificity remained high (94.2%). Most of the missed cases (72.5%) had clinically insignificant stage I prolapse. If we defined symptomatic
True disease status
4–10 ⬎10–20 ⬎20–30a ⬎30–40 ⬎40–50 ⬎50–60 ⬎60 Total 1 0 1
Disease status by questionnaire Group A Group B Total
Table 6 Discrimination analyses for sensitivity and specificity for question in the screening study if we defined symptomatic prolapse as stage II
Table 4 Distribution of scores yielded from the five questions selected for the final questionnaire by patient category Group 1b 5 9 Group 2c 161 20 Total 166 29
True disease status
110 200 0 199 110 399
Disease status by questionnaire
Stage I–IV
Stage 0–1
Total
Group A Group B Total
120 22 144
42 98 140
162 120 282
Sensitivity: 84.5% (95% CI 77.7–89.5) Specificity: 70.0 (95% CI 62.0–77.0) Positive predictive value: 74.1% (95% CI 66.8–80.2) Negative predictive value: 81.7% (95% CI 73.8–87.6)
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prolapse as stage II or higher, the sensitivity increased and the specificity dropped. Strengths of this study include the sequential approach, with evaluation of the questionnaire in an independent, population-based sample; the comparably large sample sizes; and the standardized clinical evaluation of the participants. Important caveats are the low participation rate in the phase 2 clinical investigation of 282 women whose scores indicated total absence of prolapse and uncertainty about what should be considered clinically significant prolapse. The regression toward poorer performance of the test in a new, independent test sample, compared with the actively optimized performance in the study group used during the developmental phase, is a universal and thus expected phenomenon. It shows that a second test phase is necessary to get a correct view of the qualities of a newly developed instrument. The selective drop in sensitivity, however, is probably not exclusively caused by regression toward the mean. The women with prolapse in the original sample were classified according to Becham, whereas the others were more rigorously classified according to POPQ. Because most of the former were on the waiting list for surgery and had clinically evident prolapse (at least stage II, i.e., down to the introitus), misclassification of prolapse status (yes or no) should not have been a major problem. The absence of stage I prolapse in this group probably contributed to the poorer sensitivity to detect such cases in our resulting questionnaire when used in the general population, but this limitation was intentional. First, we aimed to identify clinically significant prolapse. Although the course of clinically silent stage I prolapse in nonpatients is essentially unexplored, such prolapse seems to be common in the population [3,4,10], and perhaps most of these women will never develop clinically important disease. Accordingly, in clinical and epidemiologic studies, whether they are descriptive or analytic, inclusion of silent stage I prolapse is generally not desired. Second, there is always a trade-off between the sensitivity and specificity of diagnostic tests. An increased sensitivity almost inevitably comes about at the expense of the specificity. For diseases that affect no more than a fraction of the population, imperfect specificity is much more serious than poor sensitivity. Even if the false-positive rate is small, it is multiplied by the large disease-free population. Hence, the number of subjects who are misclassified as cases may be substantial and might exceed the number of correctly classified cases. An imperfect sensitivity is much less detrimental. The false-negative rate is multiplied by the usually small fraction of the population that truly has the disease, so the number of true cases that are misclassified as being disease free is generally small. In a case-control analysis, these few cases are diluted by all correctly classified diseasefree subjects, resulting in a more or less negligible impact on the results. Therefore, specificity is generally prioritized before sensitivity in instruments designed for case finding in cross-sectional epidemiologic studies.
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Because there were lower participation rates among women in Group B, it seems that women without the slightest suspicion of prolapse were less motivated to come for an examination. This probably resulted in a concentration of women with prolapse among attendees in group B, with an artifactually inflated false-negative rate, reduced sensitivity, and underestimated NPV as obvious consequences. In other studies with self-reported symptoms of genital organ prolapse, phrases like “sensing something coming down in the vagina” [1,2,11] were used to describe genital organ prolapse. Almost 15 years ago, a subgroup of a WHO technical working group [12] formulated four questions to elicit the presence of genital organ prolapse: Do you feel anything coming out of your vagina? Do you have a feeling of heaviness? Is it uncomfortable down below? Do you need to manipulate it to urinate or defecate? The subgroup thought that these questions could identify 80% to 90% of genital organ prolapse cases. This assumption is essentially confirmed by our data, which show that the question “Do you have a sensation of tissue protrusion (vaginal bulge) from the vagina?” carried almost all of the predictive ability of all initial 13 questions combined. The strength of this question, the answer of which indicates a significant anatomic dislocation, is probably due to the fact that all of our prolapse-positive cases in the first phase of the study had symptomatic prolapse of stage II or higher and that the symptoms, especially local symptoms, increase with increasing POPQ stage [13,14]. Partly in conflict with the assumptions by the WHO subgroup [12], however, the question “Do you have difficulties emptying your bowels?” had no predictive value in our study. The question is more likely to identify women with constipation, which was previously shown to be unrelated to severity of posterior vaginal prolapse [15,16]. Our data confirm findings by others indicating that constipated women without any prolapse of the posterior wall commonly use manual pressure to complete defecation [15]. Although constipation does not seem to be a marker of current prolapse, it may be a risk factor for this condition and may thus precede its onset. This was suggested in a case control study [16] but was refuted in another study [17]. Pelvic floor support follows a continuum from perfect to total absence. The lack of agreement about where to place the cutpoint between health and disease and the weak scientific foundation for such agreement complicate the construction of measurement instruments and the interpretation of their results. The women tend to define the condition in terms of symptoms, whereas the POPQ bases its classification on anatomic findings. Clinicians (and patients) would probably be most helped by indices that point to an adverse outcome and thus a need for treatment. Therefore, prospective studies of the natural course in symptom-free women with stage I prolapse are warranted. It is reasonable to assume that a minority (the youngest?) has a progressive disease that requires intervention, whereas the majority has changes that
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are more or less stable and that will not develop into symptomatic disease. To find markers of an unfavorable prognosis and to incorporate them into an instrument such as ours is a challenge for the future. In conclusion, our study provides some insights into the relative usefulness of questions often asked during history taking in genital organ prolapse. Five simple questions identify clinically significant prolapse with high specificity and reasonable sensitivity. Thus, this instrument is useful for ruling in cases in epidemiologic investigations. Studies of the importance of asymptomatic stage I prolapse, often missed by our questionnaire, are warranted to refine the borderline between normal and pathologic lack of pelvic floor support. References [1] MacLennan AH, Taylor A, Wilson DH, Wilson D. The prevalence of pelvic floor disorders and their relationship to gender, age, parity and mode of delivery. Br J Obstet Gynaecol 2000;107:1460–70. [2] Kumari S, Walia I, Singh A. Self-reported uterine prolapse in a resettlement colony of North India. J Midwifery Women’s Health 2000;45: 343–9. [3] Swift E. The distribution of pelvic organ support in a population of female subjects seen for routine gynecologic health care. Am J Obstet Gynecol 2000;183:277–85. [4] Bland DR, Earle BB, Vitolinis MZ, Burke G. Use of the pelvic organ prolapse staging system of the International Continence Society, American Urogynecologic Society, and Society of Gynecologic Surgeons in perimenopusal women. Am J Obstet Gynecol 1999;181: 1324–8. [5] Beecham CT. Classification of vaginal relaxation. Am J Obstet Gynecol 1980;136:957–8.
[6] Bump RC, Mattiasson A, Bo K, Brubaker LP, Delancey JOL, Klarskov P, et al. The standardisation of terminology of female prolapse and pelvic floor dysfunction. Am J Obstet Gynecol 1996;175:10–7. [7] Weber AM, Abrams P, Brubaker G, Cundiff G, Davis G, Dmochowski RR, Nygaard I, Weidner AC. The standardization of Terminology for Researchers in Female Pelvic Floor Disorders. Int Urogynecol J 2001;12:178–86. [8] Altman DG, Machin D, Bryant TN, Gardner MJ. Statistics with confidence. London: BMJ Books; 2002. [9] Hosmer DW, Lemeshow S. Applied logistic regression. New York: Wiley; 2000. [10] Samuelsson EC, Victor A, Tibblin G, Sva¨rdsudd KF. Signs of genital prolapse in a Swedish population of women 20 to 59 years of age and possible related factors. Am J Obstet Gynecol 1999;180:299–305. [11] Gonza les-Argente FX, Jain A, Nogueras JJ, Davila W, Weiss EG, Wexner SD. Prevalence and severity of urinary incontinence and pelvic genital prolapse in females with anal incontinence or rectal prolapse. Dis Colon Rectum 2001;44:920–6. [12] World Health Organization. Measuring reproductive morbidity: report of technical working group. WHO/MCH/90.4. Geneva: Division of Family Planning; 1989. [13] Otto L, Urankar R, Clark A. Correlation of symptoms of pelvic organ prolapse to clinical stage [abstract]. Int Urogynecol J 1999;10(Suppl 1): S25. [14] Ellerkmann RM, Cundiff W, Melick CF, Nihira A, Leffler K, Bent AE. Correlation of symptoms with location and severity of pelvic organ prolapse. Am J Obstet Gynecol 2001;185:1332–8. [15] Weber AM, Walters MD, Ballard LA, Booher MD, Piedmonte MR. Posterior vaginal prolapse and bowel function. Am J Obstet Gynecol 1998;179:1446–50. [16] Spence-Jones C, Kamm MA, Henry MM, Hudson CN. Bowel dysfunction: a pathogenic factor in uterovaginal prolapse and urinary stress incontinence. Br J Obstet Gynaecol 1994;101:147–52. [17] Hendrix SL, Clark A, Nygaard I, Aragaki A, Barnabei V, McTiernan A. Pelvic organ prolapse in the Women’s Health Initiative. Gravity and gravidity. Am J Obstet Gynecol 2002;186:1160–6.
A short-form questionnaire identified genital organ prolapse Gunilla Tegerstedta,b,c,*, Ann Miedela,c, Marianne Maehle-Schmidtb, Olof Nyrenb,c, Margareta Hammarstro¨ma,c,d a
Department of Obstetrics and Gynaecology, Karolinska Institutet, Stockholm So¨der Hospital, Stockholm S-118 83, Sweden b Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm S-118 83, Sweden c Clinical Epidemiology Unit, Department KI, So¨der Hospital, Stockholm S-118 83, Sweden d Octaviakliniken, Tideliusgatan 22, 11869 Stockholm Accepted 9 June 2004
Abstract Objective: We constructed a simple questionnaire that, with a minimum of questions, could accurately and reliably identify women with genital organ prolapse. Study Design and Setting: Two hundred women with confirmed genital organ prolapse and 199 outpatients with various gynecologic symptoms but no objective prolapse answered 13 questions perceived to be valuable for the diagnosis. With stepwise backward logistic regression, the discriminatory ability of a successively abbreviated set of questions was assessed. The resulting short questionnaire was tested in a new population-based sample of 282 women participating in a screening survey. Results: A final five-item questionnaire retained 94% of the predictive value of all 13 questions and had 92.5% sensitivity and 94.5% specificity in the first group of women. When the questionnaire was used in the subsequent population-based survey, the sensitivity and specificity values were 66.5% and 94.2%, respectively. Most missed cases had stage I prolapse. Conclusion: Although the sensitivity of the test was moderate, the specificity, and hence the ability to rule in cases, was satisfactory. The test is suitable for case finding in epidemiologic studies. 쑖 2005 Elsevier Inc. All rights reserved. Keywords: Questionnaire; Genital organ prolapse; Validation; Prolapse-related symptoms
1. Introduction The common patient history remains a cornerstone in everyday practice, yet its diagnostic performance is essentially unexplored for many common conditions. Which questions need to be asked, and at which point do additional questions become superfluous? The concern about redundant data collection is particularly justifiable in epidemiologic studies, where unnecessarily long questionnaires may hamper response rates. Symptoms of pelvic floor disorders in women are a common cause for medical contacts. Estimations of prevalence of genital organ prolapse reported in the literature range from 4.4% to 50% [1–4]. This vast variation suggests that definitions and epidemiologic methodologies may require careful consideration. Valid and reliable data on the true prevalence is important for the planning of health care for
* Corresponding author. Department of Obstetrics and Gynaecology, Karolinska Institutet, Stockholm So¨der Hospital, Stockholm S-118 83, Sweden. Tel.: ⫹44 8 616 26 46; fax: ⫹44 8 616 43 93. E-mail address: [email protected] (G. Tegerstedt). 0895-4356/04/$ – see front matter 쑖 2005 Elsevier Inc. All rights reserved. doi: 10.1016/j.jclinepi.2004.06.008
women and for putting the clinical finding of genital organ prolapse in an individual patient into perspective. The aim with this study was to construct a short questionnaire that, with a minimum of questions, retained the ability to discriminate between women with and without genital organ prolapse. 2. Methods 2.1. Phase 1: Development of the questionnaire We compiled 13 questions perceived to be valuable for the diagnosis and therefore often used in medical history taking (Table 1). To evaluate the sensitivity of these questions, alone or in various combinations, they were administered to 200 women with confirmed genital organ prolapse attending the outpatient clinic for symptoms or being on the waiting list for surgery. All women were routinely examined by a gynecologist at the Department of Obstetrics and Gynecology, Stockholm So¨der Hospital, using the Becham classification [5]. All had second- or third-degree prolapse, which means that the prolapse had reached the introitus or beneath.
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Table 1 The 13 questions used in the first part of the investigation Question 1. 2. 3. 4.
Do you have a sensation of vaginal heaviness or pressure? Do you have a sensation of tissue protrusion (vaginal bulge) from vagina? Do you suffer from scraping in your vagina/vulva? Has a doctor, in connection with a gynecologic examination, told you that you have a genital organ prolapse? 5. If you have symptoms, are they different during the day? 6. Are your symptoms worse during stress, for example, during heavy lifting? 7. Do you have difficulties emptying your bladder? 8. Do you have difficulties emptying your bowels? 9. Do you have to lift the anterior vaginal wall to start or complete voiding? 10. Do you have to do a digital manipulation of the vagina, perineum, or anus to complete voiding? 11. Do you suddenly feel the urge to go to the toilet, and then accidentally leak urine? 12. Do you leak urine during coughing, sneezing, or heavy lifting? 13. Do you believe that you have genital organ prolapse?
The specificity was evaluated in another 199 women coming to the outpatient clinic for various gynecologic problems (e.g., dysfunctional bleedings, menopausal symptoms, or cervical dysplasia) but in whom genital organ prolapse was excluded by one of the gynecologists in the research team. The pelvic floor anatomy was defined in conformity with standards recommended by the International Continence Society, the pelvic organ prolapse quantification system (POPQ) [6]. Only women with no demonstrable prolapse (stage 0) were accepted in this group. To assess reproducibility of the answers, 100 women from each group were given the same questions a second time 1 month later.
A
B
C
D
Yes, often Yes, often Yes, often Yes
Sometimes Sometimes Sometimes No
Infrequently Infrequently Infrequently I don’t know
No, ever No, ever No, ever
Worse morning Unchanged Yes, often Yes, often Yes, often Yes, often
Worse day Better Sometimes Sometimes Sometimes Sometimes
Worse dinner Worse Infrequently Infrequently Infrequently Infrequently
Worse evening No, ever No, ever No, ever No, ever No, ever
Yes, often Yes, often Yes
Sometimes Sometimes No
Infrequently Infrequently I don’t know
No, ever No, ever
The most powerful short set of questions (see STATISTICAL was sent to a random sample (n ⫽ 8,000) of the Stockholm female population 29–79 years of age. The response rate was 69%. Among women whose scores were indicative of symptomatic genital organ prolapse, we randomly selected 206 who were invited to a standardized gynecologic examination following the principles of the POPQ. We randomly selected 206 women whose answers indicated absence of genital organ prolapse. The participation in this second phase of the investigation was 79% (n ⫽ 162) and 58% (n ⫽ 120), respectively, among those with and without a positive questionnaire result. Only complete absence of prolapse (stage 0) was defined as nonprolapse. Stages I through IV were defined as prolapse in accordance with the recommended standard terminology for research of pelvic support defects [7].
questions. The cutpoints for positive response to each question were based on visual inspection of response distributions and on prior clinical experience. To select a minimal set of questions that best distinguished between prolapse and nonprolapse women, the following strategy was adopted: We evaluated the diagnostic value of each question in univariate logistic regression models. Then various combinations of the questions were evaluated in multivariate logistic regression models using stepwise backward elimination to arrive at a preliminary multivariate model. The stepwise approach was assumed to work well because there were few missing values in the data. We adjusted for age in all multivariate logistic regression models. The effect of collapsing or extending the number of categories for the questions was evaluated in the resulting preliminary multivariate model. To ensure selection of the most powerful combinations of questions, we evaluated the effect of each of the previously eliminated variables in the new preliminary multivariate model before the final model was chosen. Adjusted odds ratio (OR) scores from the final logistic regression model were tested in discriminant analyses for the development of a discriminant criterion according to which the participating women in the Stockholm sample were classified. We calculated positive and negative predictive values (NPVs) in our studied population sample, emphasizing that these values are dependent on the prevalence of prolapse among the individuals being investigated. Kappa scores evaluated reproducibility. For questions 4, 5, 6, and 11, simple kappa scores were calculated. We used weighted scores for all other questions [9]. This study was approved by the Local Ethics Committee at Karolinska Institutet.
2.3. Statistical methods
3. Results
2.2. Phase II: Testing the questionnaire in an independent sample METHODS)
In the groups of 200 and 199 women with confirmed presence or absence, respectively, of genital prolapse, we calculated crude sensitivity and specificity values with 95% confidence intervals (CI) [8] for each of the 13 original
3.1. Phase 1: Development of a questionnaire The mean age among subjects with pelvic organ prolapse (68 years, median 66.7, range 32–92) was higher than in
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the group without (52 years, median 52, range 33–80). The crude sensitivity and specificity values and the reproducibility for each of the 13 questions in the first round are shown in Table 2. The cutpoints used for a positive prolapse categorization are given in the Table 2. The sensitivity ranged from 21% (question 10 “Do you have to do a digital manipulation of the vagina, perineum, or anus to complete voiding?”) to 89% (question 4 “Has a doctor, in connection with a gynecologic examination, told you that you have a genital organ prolapse?”). The specificity ranged from 71% (question 12 “Do you leak urine during coughing, sneezing, or heavy lifting?”) to 98% (question 13 “Do you believe that you have genital organ prolapse?” and question 9 “Do you have to lift the anterior vaginal wall to start or complete voiding?”). The sensitivity of question 13 was artificially high because most of the women with prolapse were already informed about the condition for which they were on the surgical waiting list. The kappa values ranged from 0.61 (question 5 “If you have symptoms, are they different during the day?”) to 0.94 (question 4), and the majority of questions had kappa values exceeding 0.8, indicating almost perfect agreement between answers given 1 month apart. When combining both groups of patients to estimate the importance of each question and its ability to add to the overall
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predictive ability, the resulting logistic regression model after stepwise elimination of redundant questions consisted of questions 2, 6, 9, and 11 together with age that was forced into the model. The OR scores from this logistic regression model were passed to the discriminant analysis. Then scores were adjusted, and question 3 was added to slightly improve the discrimination results. The final model scores are given in Table 3, and the result from the discriminant analysis is given in Table 4. We defined the cut-off value for prolapse at 30 points. Scores higher than 30 represent a positive response for prolapse (Table 4). Questions 2 and 9 carried almost all of the discriminative ability of the test; a model including only age and these two questions performed almost as well as the model including all six pieces of information. A cross-tabulation of test result based on questions 2, 3, 6, 9, and 11 by true diseased status resulted in a sensitivity and specificity of 92.5% and 94.5%, respectively. The positive predictive value (PPV) in this rather artificial mix of prolapse-positive and prolapse-negative women was 94.4%, and the NPV was 92.6%. 3.2. Phase 2: Test of the questionnaire in an independent sample Of 8,000 short-form questionnaires sent out to women living in Stockholm, 5,501 were returned with complete
Table 2 Responses to questionnaire Question about 1 Vaginal heaviness/pressure
Groupa A (%)
1 2 2 Tissue protrusion/vaginal bulge 1 2 3 Vaginal pain/comfort 1 2 4 Knowledge about prolapse 1 2 5 Variation of symptom during day 1 2 6 Heavy lift 1 2 7 Voiding difficulty 1 2 8 Difficulty with defecation 1 2 9 Manual reduction of anterior wall 1 2 10 Digital manipulation to 1 complete defecation 2 11 Urge incontinence 1 2 12 Stress incontinence 1 2 13 Do you imagine that you have 1 a genital organ prolapse? 2 a b
98 9 122 0 35 7 178 10 16 3 43 40 45 4 42 15 16 1 21
(49) (4.5) (61)
3 49 7 60 18 189
B (%)
C (%)
D (%)
(14.5) A ⫹ B versus C ⫹ D (68) 76% (69–81) 89% (83–93) (8) A ⫹ B versus C ⫹ D (91) 86% (80–90) 98% (94–99) (41.5) A ⫹ B versus C ⫹ D (82) 43% (36–49) 98% (94–99) A versus B ⫹ C 89% (84–93) 95% (91–97) (23) B ⫹ D versus A (4.5) 89% (83–93) 13% (5–32) C versus A ⫹ B 76% (69–81) 70% (57–81) (29) A ⫹ B versus C ⫹ D (70) 49% (42–56) 91% (87–95) (36.5) A ⫹ B versus C ⫹ D (51) 44% (37–51) 77% (71–83) (70.5) A ⫹ B ⫹ C versus D (97.5) 28% (22–35) 99% (96–100) (64.5) A ⫹ B versus C ⫹ D
(17.5) (3.5) (89) (5) (8) (1.5) (21.5) (20) (22.5) (2.3) (21) (7.5) (8) (0.5) (10.5)
53 13 49 5 50 9 19 184 32 5 3 0 53 13 46 30 20 0 20
(27) (6.5) (25) (2.5) (25) (4.5) (9.5) (92) (16) (2.5) (1.5)
20 42 13 12 32 17 3 5 52 6 143 17 (26.5) 44 (6.5) 38 (23) 41 (15) 52 (10) 19 2 (10) 27
(10) (21) (6.5) (6) (16) (8.5) (1.5) (2.5) (26.6) (3) (71.5) (8.5) (22) (19) (20.5) (26) (9.5) (1) (13.5)
(1.5) (24.5) (3.5) (30) (9) (95)
9 56 36 47 40 2
(4.5) (28) (18) (23.5) (20) (1)
(6) 175 (87.5) 21% (16–27) 94% (90–97) (30.5) 34 (17) A ⫹ B versus C ⫹ D (40.7) 75 (37.6) 53% (46–59) 78% (72–84) (23) 47 (23.5) A ⫹ B versus C ⫹ D (44.2) 53 (26.6) 54% (47–60) 71% (64–77) (4.5) A versus B ⫹ C
3 (1.5)
162 (82)
12 61 81 46 88 9
34 (17)
29 135 16 182 83 164
Specificityb Sensitivityb (95% CI) (95% CI)
46 9
58 140 71 102 141 195 129
95% (90–97)
Group 1, subjects with genital organ prolapse, n ⫽ 200; group 2, subjects without any prolapse, n ⫽ 199. Sensitivity and specificity are tested in different alternative of answers.
Kappa value 0.84 (0.78–0.89) 0.89 (0.85–0.93) 0.72 (0.64–0.79) 0.94 (0.89–0.99) 0.61 (0.46–0.75) 0.55 (0.40–0.69) 0.82 (0.76–0.87) 0.76 (0.69–0.82) 0.83 (0.73–0.93)
0.76 (0.69–0.83) 0.76 (0.69–0.83) 0.81 (0.75–0.86)
99% (96–100) 0.90 (0.89–0.99)
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Table 3 The final models score. Adjusted odds ratio scores from the final questionnaire
Table 5 Discrimination analyses for sensitivity and specificity for questions 2, 3, 6, 9, 11 in part two, the screening study
Question about
Answer
Score
Age
⬍50 ⬎70 50 ⬍ age ⬍ 70 Yes, often Sometimes/infrequently Never Yes, often Sometimes/infrequently Never Worse Unchanged/better Yes, often/sometimes/ infrequently Never Yes, often Sometimes/infrequently Never
0.2 3 1 50 30 1 5 0.2 1 10 1 11
2. Tissue protrusion/vaginal bulge
3. Vaginal pain/discomfort
6. Heavy lifting 9. Manual reduction of anterior wall 11. Urge incontinence
1 5 0.7 1
answers. The age information from the women was compared with the age information from SPAR, a continuously updated population register. Eleven of the women who answered the questionnaire were eliminated from the analyses because of inconsistencies in age information, leaving a total of 5,490 women in the study population. Every woman was classified through applying the scores derived from the first part of the study. Of the 5,490 women, 454 were classified as having genital organ prolapse with symptoms classified as having no genital organ prolapse. Forty-eight women could not be classified due to missing answers to one or more of the symptom questions. Among the 454 women classified as having genital organ prolapse, 206 were randomly sampled for clinical investigation. Another random sample of 206 women whose scores indicated absence of genital organ prolapse was invited. Two hundred eighty-two of the sampled women came to the examination (68%; Table 6). In Group A (women with prolapse according to the questionnaire), 162 women (79%) participated, and in Group B (women classified by the questionnaire as having no prolapse) 120 (58%) showed up. The POPQ prolapse stages in Group A were as follows: stage 0, 1.9%; stage I, 24.1%; stage II, 59.3%; stage III, 11.7%, and stage IV, 3.1%. In Group B, stage 0 was observed in 33.3%,
a b c
19 11 30
32 6 38
Scores ⬎30, positive response for prolapse. Group 1: 200 women with prolapse. Group 2: 199 women without prolapse.
24 1 25
Stage I–IV
Stage 0
Total
159 80 239
3 40 43
162 120 282
Subjects defined as symptomatic prolapse (group A, n ⫽ 162) or symptomless group B, n ⫽ 120) and examined with pelvic organ prolapse quantification system stage I–IV classified as prolapse (stage 0, absent of prolapse). Sensitivity: 66.5% (95% CI 60.3–72.2) Specificity: 94.2% (95% CI 84.4–98.0.6) Positive predictive value: 98.1% (95% CI 94.7–99.4) Negative predictive value: 38.0% (95% CI 30.1.8–46.6)
stage I in 48.3%, stage II in 17.5%, and stage III in 0.8%. No one in this group had stage IV prolapse. A cross-tabulation (Table 5) reveals that our short-form questionnaire, consisting of only five questions, had a sensitivity of 66.5%, a specificity of 94.2%, a PPV of 98.1%, and a NPV of 38.0% in the population-based survey. Of the false-negative cases (58/80), 72.5% had stage I prolapse, the clinical significance of which is often doubtful. Had we defined symptomatic prolapse as stage II or higher according to POPQ, the sensitivity of our questionnaire would increase to 84.5% (95% CI 77.7–89.5), and the specificity would have dropped to 70.0% (95% CI 62.0–77.0). The corresponding positive and negative values would be 74.1% and 81.7% (Table 4). 4. Discussion We aimed to construct a questionnaire that, with a minimal number of questions, could accurately and reliably identify women with true genital organ prolapse. Five questions, supplemented with information about age, provided essentially all of the discriminatory power of an original set of 13 questions. The sensitivity and specificity were 92.5% and 94.5%, respectively, in the original patient population. In a subsequent population-based survey, the sensitivity was lower (66.5%), whereas the specificity remained high (94.2%). Most of the missed cases (72.5%) had clinically insignificant stage I prolapse. If we defined symptomatic
True disease status
4–10 ⬎10–20 ⬎20–30a ⬎30–40 ⬎40–50 ⬎50–60 ⬎60 Total 1 0 1
Disease status by questionnaire Group A Group B Total
Table 6 Discrimination analyses for sensitivity and specificity for question in the screening study if we defined symptomatic prolapse as stage II
Table 4 Distribution of scores yielded from the five questions selected for the final questionnaire by patient category Group 1b 5 9 Group 2c 161 20 Total 166 29
True disease status
110 200 0 199 110 399
Disease status by questionnaire
Stage I–IV
Stage 0–1
Total
Group A Group B Total
120 22 144
42 98 140
162 120 282
Sensitivity: 84.5% (95% CI 77.7–89.5) Specificity: 70.0 (95% CI 62.0–77.0) Positive predictive value: 74.1% (95% CI 66.8–80.2) Negative predictive value: 81.7% (95% CI 73.8–87.6)
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prolapse as stage II or higher, the sensitivity increased and the specificity dropped. Strengths of this study include the sequential approach, with evaluation of the questionnaire in an independent, population-based sample; the comparably large sample sizes; and the standardized clinical evaluation of the participants. Important caveats are the low participation rate in the phase 2 clinical investigation of 282 women whose scores indicated total absence of prolapse and uncertainty about what should be considered clinically significant prolapse. The regression toward poorer performance of the test in a new, independent test sample, compared with the actively optimized performance in the study group used during the developmental phase, is a universal and thus expected phenomenon. It shows that a second test phase is necessary to get a correct view of the qualities of a newly developed instrument. The selective drop in sensitivity, however, is probably not exclusively caused by regression toward the mean. The women with prolapse in the original sample were classified according to Becham, whereas the others were more rigorously classified according to POPQ. Because most of the former were on the waiting list for surgery and had clinically evident prolapse (at least stage II, i.e., down to the introitus), misclassification of prolapse status (yes or no) should not have been a major problem. The absence of stage I prolapse in this group probably contributed to the poorer sensitivity to detect such cases in our resulting questionnaire when used in the general population, but this limitation was intentional. First, we aimed to identify clinically significant prolapse. Although the course of clinically silent stage I prolapse in nonpatients is essentially unexplored, such prolapse seems to be common in the population [3,4,10], and perhaps most of these women will never develop clinically important disease. Accordingly, in clinical and epidemiologic studies, whether they are descriptive or analytic, inclusion of silent stage I prolapse is generally not desired. Second, there is always a trade-off between the sensitivity and specificity of diagnostic tests. An increased sensitivity almost inevitably comes about at the expense of the specificity. For diseases that affect no more than a fraction of the population, imperfect specificity is much more serious than poor sensitivity. Even if the false-positive rate is small, it is multiplied by the large disease-free population. Hence, the number of subjects who are misclassified as cases may be substantial and might exceed the number of correctly classified cases. An imperfect sensitivity is much less detrimental. The false-negative rate is multiplied by the usually small fraction of the population that truly has the disease, so the number of true cases that are misclassified as being disease free is generally small. In a case-control analysis, these few cases are diluted by all correctly classified diseasefree subjects, resulting in a more or less negligible impact on the results. Therefore, specificity is generally prioritized before sensitivity in instruments designed for case finding in cross-sectional epidemiologic studies.
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Because there were lower participation rates among women in Group B, it seems that women without the slightest suspicion of prolapse were less motivated to come for an examination. This probably resulted in a concentration of women with prolapse among attendees in group B, with an artifactually inflated false-negative rate, reduced sensitivity, and underestimated NPV as obvious consequences. In other studies with self-reported symptoms of genital organ prolapse, phrases like “sensing something coming down in the vagina” [1,2,11] were used to describe genital organ prolapse. Almost 15 years ago, a subgroup of a WHO technical working group [12] formulated four questions to elicit the presence of genital organ prolapse: Do you feel anything coming out of your vagina? Do you have a feeling of heaviness? Is it uncomfortable down below? Do you need to manipulate it to urinate or defecate? The subgroup thought that these questions could identify 80% to 90% of genital organ prolapse cases. This assumption is essentially confirmed by our data, which show that the question “Do you have a sensation of tissue protrusion (vaginal bulge) from the vagina?” carried almost all of the predictive ability of all initial 13 questions combined. The strength of this question, the answer of which indicates a significant anatomic dislocation, is probably due to the fact that all of our prolapse-positive cases in the first phase of the study had symptomatic prolapse of stage II or higher and that the symptoms, especially local symptoms, increase with increasing POPQ stage [13,14]. Partly in conflict with the assumptions by the WHO subgroup [12], however, the question “Do you have difficulties emptying your bowels?” had no predictive value in our study. The question is more likely to identify women with constipation, which was previously shown to be unrelated to severity of posterior vaginal prolapse [15,16]. Our data confirm findings by others indicating that constipated women without any prolapse of the posterior wall commonly use manual pressure to complete defecation [15]. Although constipation does not seem to be a marker of current prolapse, it may be a risk factor for this condition and may thus precede its onset. This was suggested in a case control study [16] but was refuted in another study [17]. Pelvic floor support follows a continuum from perfect to total absence. The lack of agreement about where to place the cutpoint between health and disease and the weak scientific foundation for such agreement complicate the construction of measurement instruments and the interpretation of their results. The women tend to define the condition in terms of symptoms, whereas the POPQ bases its classification on anatomic findings. Clinicians (and patients) would probably be most helped by indices that point to an adverse outcome and thus a need for treatment. Therefore, prospective studies of the natural course in symptom-free women with stage I prolapse are warranted. It is reasonable to assume that a minority (the youngest?) has a progressive disease that requires intervention, whereas the majority has changes that
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are more or less stable and that will not develop into symptomatic disease. To find markers of an unfavorable prognosis and to incorporate them into an instrument such as ours is a challenge for the future. In conclusion, our study provides some insights into the relative usefulness of questions often asked during history taking in genital organ prolapse. Five simple questions identify clinically significant prolapse with high specificity and reasonable sensitivity. Thus, this instrument is useful for ruling in cases in epidemiologic investigations. Studies of the importance of asymptomatic stage I prolapse, often missed by our questionnaire, are warranted to refine the borderline between normal and pathologic lack of pelvic floor support. References [1] MacLennan AH, Taylor A, Wilson DH, Wilson D. The prevalence of pelvic floor disorders and their relationship to gender, age, parity and mode of delivery. Br J Obstet Gynaecol 2000;107:1460–70. [2] Kumari S, Walia I, Singh A. Self-reported uterine prolapse in a resettlement colony of North India. J Midwifery Women’s Health 2000;45: 343–9. [3] Swift E. The distribution of pelvic organ support in a population of female subjects seen for routine gynecologic health care. Am J Obstet Gynecol 2000;183:277–85. [4] Bland DR, Earle BB, Vitolinis MZ, Burke G. Use of the pelvic organ prolapse staging system of the International Continence Society, American Urogynecologic Society, and Society of Gynecologic Surgeons in perimenopusal women. Am J Obstet Gynecol 1999;181: 1324–8. [5] Beecham CT. Classification of vaginal relaxation. Am J Obstet Gynecol 1980;136:957–8.
[6] Bump RC, Mattiasson A, Bo K, Brubaker LP, Delancey JOL, Klarskov P, et al. The standardisation of terminology of female prolapse and pelvic floor dysfunction. Am J Obstet Gynecol 1996;175:10–7. [7] Weber AM, Abrams P, Brubaker G, Cundiff G, Davis G, Dmochowski RR, Nygaard I, Weidner AC. The standardization of Terminology for Researchers in Female Pelvic Floor Disorders. Int Urogynecol J 2001;12:178–86. [8] Altman DG, Machin D, Bryant TN, Gardner MJ. Statistics with confidence. London: BMJ Books; 2002. [9] Hosmer DW, Lemeshow S. Applied logistic regression. New York: Wiley; 2000. [10] Samuelsson EC, Victor A, Tibblin G, Sva¨rdsudd KF. Signs of genital prolapse in a Swedish population of women 20 to 59 years of age and possible related factors. Am J Obstet Gynecol 1999;180:299–305. [11] Gonza les-Argente FX, Jain A, Nogueras JJ, Davila W, Weiss EG, Wexner SD. Prevalence and severity of urinary incontinence and pelvic genital prolapse in females with anal incontinence or rectal prolapse. Dis Colon Rectum 2001;44:920–6. [12] World Health Organization. Measuring reproductive morbidity: report of technical working group. WHO/MCH/90.4. Geneva: Division of Family Planning; 1989. [13] Otto L, Urankar R, Clark A. Correlation of symptoms of pelvic organ prolapse to clinical stage [abstract]. Int Urogynecol J 1999;10(Suppl 1): S25. [14] Ellerkmann RM, Cundiff W, Melick CF, Nihira A, Leffler K, Bent AE. Correlation of symptoms with location and severity of pelvic organ prolapse. Am J Obstet Gynecol 2001;185:1332–8. [15] Weber AM, Walters MD, Ballard LA, Booher MD, Piedmonte MR. Posterior vaginal prolapse and bowel function. Am J Obstet Gynecol 1998;179:1446–50. [16] Spence-Jones C, Kamm MA, Henry MM, Hudson CN. Bowel dysfunction: a pathogenic factor in uterovaginal prolapse and urinary stress incontinence. Br J Obstet Gynaecol 1994;101:147–52. [17] Hendrix SL, Clark A, Nygaard I, Aragaki A, Barnabei V, McTiernan A. Pelvic organ prolapse in the Women’s Health Initiative. Gravity and gravidity. Am J Obstet Gynecol 2002;186:1160–6.