Prevalence of Atypical Chest Pain Descriptions in a Population from the Southern United States

Prevalence of Atypical Chest Pain Descriptions in a Population from the Southern United States RICHARD L. SUMMERS, MD; GEORGE J. COOPER, MD; MICHAEL E. ANDREWS, PHD; JAMES C. KOLB, MD

FREDERICK B. CARLTON, MD;

ABSTRACT: Introduction: The character of chest pain (CP) is a major factor determining triage and admission for patients presenting to the emergency department (ED). Previous studies have found atypical descriptions in as little as 10-15% of patients with true myocardial ischemic pain. Atypical descriptions may be more prevalent in the Deep South of the United States because of cultural differences in the semantic description of pain. Methods: A retrospective study of patients presenting to the ED of a southern U.S. urban hospital with enzymedocumented myocardial infarction was conducted to determine the prevalence of atypical CP descriptions. A multivariate analysis of those patients with atypical pain descriptions was conducted to determine the independent demographic factors associated with these descriptions. Results: In a total of 77 subjects (56% black; 44%

white) meeting the study criteria, 43% were found to have atypical elements in the character of their CP descriptions. Only the black race demographic was found to be significantly correlated with the atypical descriptions. The use of the descriptive term "sharp" accounted for nearly half of the atypical presentations. Conclusion: Regional differences in the description of the character of CP may result in misleading portrayals of ischemic heart disease in southern U.S. populations. These differences are associated with a higher prevalence of atypical CP because of semantic distinctions, such as the use of the term "sharp" as a descriptor of acuity rather than character or quality. KEY INDEXING TERMS: Atypical angina; Chest pain; Myocardial infarction [Am J Med Sci 1999;318(3):142-5.]

M

scriptions of chest pain during acute myocardial infarction is considered to be around 15% for the broad U.S. population. 6 Classical infarction angina is described as having a pressure or squeezing character on the World Health Organization, Rose, and other questionnaires. 7 ,s These descriptions were derived from surveys done in English and northeastern U.S. populations. In our experience, atypical descriptions seem to be more prevalent in the Deep South of the U.S. because of regional and cultural differences in the semantic description of the character of pain. The objective of this study was to determine the prevalence of atypical chest pain descriptions in patients with acute myocardial infarction presenting to the emergency department of a southern U.s. urban hospital and to explore the factors that contribute to the differences.

ore than 5.5 million adults present to emergency departments each year with a primary complaint of chest pain'! Of these patients, approximately 15% experience an acute myocardial infarction. The character ofthe chest pain is a major factor determining the triage and admission of these patients. Previous studies have found atypical descriptions in about 11 to 25% of the general population of patients with true myocardial ischemic pain.2-4 The rate has been shown to be fairly low in northern United States (U.S.) white and Hispanic populations (4.9% and 9.1% respectively), although this percentage seems to be significantly higher in northern U.S. urban black populations (23%).2 It is also well known that atypical descriptions are more prevalent among elderly populations ranging from about 25 to 35%.4,5 In general, the average rate of atypical de-

From the Department of Emergency Medicine, University of Mississippi Medical Center, Jackson, Mississippi. Submitted July 3, 1998; accepted in revised form October 30, 1998. Correspondence: Richard L. Summers, M.D., Associate Profes· sor, Dept of Emergency Medicine, 2500 North State Street, Jack· son, MS 39216

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Methods A retrospective study of patients presenting to an urban university medical center in the Deep South ofthe U.S. over a 2·year period (1992-94) with myocardial infarction was conducted to determine the rate of atypical chest pain descriptions. Data was retrieved from completed medical records by a single extractor and analyzed independently. The study included all known hosSeptember 1999 Volume 318 Number 3

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These groups were not further subdivided according to the individual pain descriptors that placed them in their respective subsets because of the diversity and overlap in the descriptions. A multivariate analysis was performed to isolate the independent impact of these different factors (race, sex, age, comorbid factors, residency) on the likelihood of atypical characteristics in the chest pain description. These results are reported as an odds ratio for comparison. Statistical significance was determined at a P level of 0.05.

Percent of Cohort

Results TOTAL

Black

White

Male

Female

Figure 1. Prevalence of typical and atypical chest pain descriptions in patients with acute myocardial infarction divided as to race and sex and reported as percentage of cohort.

pitalized patients over the study period with a final diagnosis of myocardial infarction that had been documented by enzyme criteria of greater than 5% ratio of creatinine phosphokinase isoenzyme (CPKMB) to creatinine phosphokinase (CPK) when there is a total elevation of CPK. This included both transmural and subendocardial infarctions; therefore, no specific electrocardiographic or echocardiographic criteria were used in the selection process. Excluded from the data set were those records in which there was insufficient information available to determine an early chest pain description (about 20%). Chest pain descriptions used were those that appeared earliest in the medical record and before the confirmation of myocardial infarction by enzyme documentation. Descriptions obtained in the emergency department were preferred but in some instances the patients were admitted from outpatient or referral sources. Subsequent descriptions were ignored even if contradictory. Differentiation of typical and atypical chest pain was based upon standard Framingham criteria with an emphasis on the character of the pain. 9 Typical chest pain characteristics were considered to be those that contained pressure, squeezing, crushing, or tightness in their descriptions. Atypical characteristics were those typically associated with a low probability of coronary artery disease (sharp, burning, stinging, indigestion).1° The data set was also examined with regard to race (black versus white), sex (male versus female), residency (rural versus metropolitan), age (>70 versus ::0;70) and presence of complicating medical conditions (diabetes, hypertension, etc.). These variables were chosen because of their previously demonstrated frequent coexistence in patients with atypical chest pain descriptions and myocardial infarction. 2 •4 •5 •10 The set of patients determined to have atypical description characteristics were separated from the typicals and each group was examined as a whole with respect to their demographic and clinical characteristics:

In a total of 77 subjects (56% black, 44% white; 55% male, 45% female) meeting the study criteria, 43% were found to have atypical elements in the character of their chest pain descriptions (Figure 1). However, within this southern population, blacks were more likely than whites to present with atypical chest pain descriptions. A majority of blacks with a documented myocardial infarction presented with atypical pain descriptions (56%) whereas only 26% of whites had atypical descriptions. Of the 77 patients, 29 (38%) were from a large metropolitan area (> 100,000 population), whereas the remainder (62%) were from rural or smaller urban populations. Although educational status was not assessed, the metropolitan patients were found to be much more likely to describe typical characteristics of anginal pain, whereas the rural population was evenly divided in their descriptions. Advanced age (>70 years) was a factor in 10 (13%), and diabetes mellitus or other complicating medical conditions were present in 17 (20%) of the total 77 patients. Of the 10 elderly patients included in the study, 80% presented typically, whereas only 41% of the patients with complicating conditions presented typically. The use of the descriptive term "sharp" accounted for nearly half of the atypical descriptions (45%). If these subjects were excluded, then only 27% of the total descriptions would be determined to be atypical. The comparative demographic results are reported in Table 1, with odds ratios calculated compared with the group least likely to have atypical

Table 1. Demographics of Patients with Documented Myocardial Infarctions P Values

Odds Ratio

43 34

0.0361

3.314

15 18 10 2

34 43 17 10

0.6604

1.252

0.3276 0.8861

1.714 0.891

10 23

29 48

0.3075

1.686

Demographics

Typical

Atypical

Total

Total Race Black White Sex Female Male Diabetic Aged (>70) Location Metropolitan Rural

44

33

77

19 25

24 9

19 25 7 8 19 25

Odds ratio is compared with the young white urban man without diabetes (the least likely to have atypical chest pain descriptions). Only the black race demographic was found to be significantly correlated with atypical chest pain descriptions. THE AMERICAN JOURNAL OF THE MEDICAL SCIENCES

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Atypical Chest Pain in the Southern United States

chest pain descriptions (the younger white urban male without diabetes). Only the black race demographic was found to be significantly correlated with atypical chest pain descriptions (P < 0.0361). When this subgroup was analyzed independently, it seemed that black women were twice as likely to present with atypical chest pain descriptions though the place of residence and complicating conditions were nearly evenly divided among the men and women of this subset. Discussion

The character of chest pain is a notably subjective component in the evaluation of patients with suspected myocardial ischemia. However, descriptions of chest pain are often a major screening factor for patients upon initial presentation to the ED. Delays in the proper triage of these patients can lead to devastating consequences. The medical community is generally taught the classic description of angina that was derived from national and northeastern U.S. population surveys. Regional differences in the description of the character of pain may result in misleading portrayals of ischemic heart disease in southern U.S. populations. This difference appears to be strongly associated with semantic differences, such as the use of the term "sharp" as a possible descriptor of acuity rather than character or quality. In fact, nearly half of the atypical descriptions could be attributed to the use of the term "sharp" as a descriptor in this southern U.S. population. This finding is disconcerting in light of the traditional view that such terms predict a very low probability of a cardiac origin for the pain. This view originates out of studies of mainly northern U.S. populations with decidedly different cultural nuances. An oftencited prospective study out of Boston reports the use of the term "sharp" to be the least predictive of myocardial infarction pain.lO This concept is so ingrained in the medical community that even the Social Security Disability Program cites the use of the term "sharp" as an exclusion factor in the description of chest pain of cardiac origin. l l In our study it is important to consider how the atypical rate may be impacted by racial differences. Clearly our results show that blacks were almost twice as likely to report atypical chest pain descriptions (56% versus 26%). This is consistent with the discrepancies in the rate of atypia found in other studies. 2 ,l2,l3 However, the total percentage of blacks examined in this study was similar to the northern U.S. studies and therefore racial population differences would not be expected to contribute to our higher total prevalence of atypia. 2 ,l3 Also, the atypical rates for both blacks and whites were higher in our southern U.S. population compared with their northern U.S. counterparts. 2 This suggests that the difference in the 144

overall rate between the northern and southern U.S. populations is more culturally derived and not simply a factor of racial differences. Educational factors have not been examined and may be a major contributing element. One other major demographic component that may be important in the differences seen is that a large portion of our population had more rural origins (62%). This rural portion also was more likely to have atypical chest pain (48% versus 34%) compared with the metropolitan participants with nearly equal percentages of races. It is uncertain whether this difference is purely educational or cultural, but we suspect that a combination of conditions is contributory, because it does not seem to be an independent risk factor for atypia. Other risk factors for atypia, such as diabetes mellitus and aging, are unlikely to be important in determining the differences seen in our study since they represented a relatively small percentage of the total patients. Female patients are sometimes cited as having a slightly higher rate of atypical chest pain descriptions. l3 ,l4 In our study, 44% of women had atypical chest pain descriptions compared with 42% of men; the female demographic did not independently increase the likelihood of atypical chest pain descriptions. Likewise, the relative portion of male and female patients in our study was also similar to the major comparative study; hence, gender should not be a major consideration in our conclusions. There are several other possible limitations to the study that should be recognized. It is easy to believe that there may be some bias in the reporting of chest pain descriptions in patients already thought by the admitting physician to be having an acute myocardial infarction. Because there were multiple interviewers involved in this portion of the data collection, there may also be inconsistencies with regard to what questions were asked. However, this retrospective approach might result in a greater tendency to report a typical description in this situation than would a prospective study. The data set was also not separated into transmural and nontransmural infarctions. There is some evidence in the literature that there is not a major difference in reporting of typical angina in these two groups; therefore, this would not be expected to significantly impact the basic hypothesis. l5 Likewise, it is unknown how many myocardial infarctions were missed in our population over the study period. In general, the number of patients sent home having an acute myocardial infarction varies in different institutions, but these people usually have a higher rate of atypical descriptions. 3 ,l6 Although these lost patients might affect the prevalence reported in this study, they would also most likely strengthen our conclusions. September 1999 Volume 318 Number 3

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Conclusions

Experienced physicians in the South and in other areas of the country with unique cultural semantics often learn to interpret what their patients really mean by their descriptions of the character of pain. There is still some confusion at times among less experienced medical personnel that could have significant consequences for their patients. It is important that we realize that the art of medicine can not be totally learned from textbooks and that disease presentations may be influenced by cultural and human variables that should not be ignored. References 1. Field JL. Perfecting MI ruleout: best practices for emergency evaluation of chest pain. Cardiology Preeminence Roundtable. Washington (DC): The Advisory Board Company; 1994. p.1-10. 2. Clark LT, Adams·Campbell LL, Maw M, et aI. Clinical features of patients with and without typical chest pain: an inner city experience. J Assoc Acad Minor Phys 1989;1:29-31. 3. Kannel WB, Abbott RD. Incidence and prognosis of unrecognized myocardial infarction. An update on the Framingham study. N Engl J Med 1984;311:1144-7. 4. Uretsky BF, Farquhar DS, Berezin AF, et al. Symptomatic myocardial infarction without chest pain: prevalence and clinical course. Am J Cardiol 1977;40:498-503. 5. Bayer AJ, Chadha JS, Farag RR, et aI. Changing presentation of myocardial infarction with increasing old age. J Am Geriatr Soc 1986;34:263-6. 6. Albrich JM, Rothrock S, SaIluzzo R. Acute myocardial

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