- Email: [email protected]
Visits to Emergency Departments for Gynecologic Disorders in the United States, 1992–1994
Visits to Emergency Departments for Gynecologic Disorders in the United States, 1992–1994 KATHRYN M. CURTIS, PhD, SUSAN D. HILLIS, PhD, BURNEY A. KIEKE, Jr, MS, KATE M. BRETT, PhD, POLLY A. MARCHBANKS, PhD, AND HERBERT B. PETERSON, MD Objective: To assess rates of visits to emergency departments for gynecologic disorders among women of reproductive age in the United States. Methods: Data from the National Hospital Ambulatory Medical Care Survey for 1992–1994 were analyzed to determine rates of visits to emergency departments among women, ages 15– 44 years. Average annual rates per 1000 women were calculated using age, race, and region-specific population estimates. Rate ratios were used to compare rates among subgroups. Results: Approximately 1.4 million gynecologic visits were made to emergency departments annually, for an average annual rate of 24.3 visits per 1000 women, ages 15– 44 years (95% confidence interval [CI] 22.0, 26.6). The most frequent diagnoses were pelvic inflammatory disease (average annual rate 5.8, 95% CI 5.0, 6.6), lower genital tract infections including sexually transmitted diseases (average annual rate 5.7, 95% CI 4.8, 6.6), and menstrual disorders (average annual rate 2.9, 95% CI 2.3, 3.5). Nearly half of all gynecologic visits resulted in diagnoses of genital tract infections. Younger women (ages 15–24 years) were 2.3 (95% CI 2.0, 2.6) times as likely as older women (ages 25– 44 years), and black women were 3.6 (95% CI 2.9, 4.3) times as likely as white women, to visit emergency departments for gynecologic disorders. Rate ratios for genital tract infections were 10 –20 times higher for younger black women than for older, white women. Conclusion: Almost half of gynecologic visits to emergency departments were related to genital tract infections, which largely are preventable. (Obstet Gynecol 1998;91: 1007–12.) From the Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia, and the Office of Analysis, Epidemiology, and Health Promotion, National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville, Maryland. The authors thank Dr. Catharine Burt for her help in accessing and interpreting these data.
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Gynecologic disorders are a common cause of hospitalization among women of reproductive age in the United States.1 Surveys of hospitalizations and physician visits are an important source of surveillance data for gynecologic disorders,2 but until recently such data have not been available for visits made to emergency departments. Therefore, it has not been known what proportion of emergency department visits are due to gynecologic disorders or, consequently, whether the prevalence of acute gynecologic disorders among women of reproductive ages has been underestimated to date. Recently, data from a nationally representative sample of emergency department visits became available for analysis. We used data from the National Hospital Ambulatory Medical Care Survey to estimate the number and rate of visits to emergency departments for gynecologic disorders among women of reproductive age in the United States.
Materials and Methods We used data from the 1992, 1993, and 1994 National Hospital Ambulatory Medical Care Survey, which has been conducted annually by the National Center for Health Statistics since 1992. The survey is a national probability sample of visits to emergency and outpatient departments of nonfederal, short-stay hospitals and is designed to be representative of all visits to emergency and outpatient departments in the United States.3– 6 We used only the emergency department portion of the data for this analysis. A four-stage probability sample design was used for the survey, including primary sampling units (ie, a geographically defined unit, such as a county, group of counties, town,
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minor civil division, or metropolitan statistical area), hospitals within these primary sampling units, emergency departments within hospitals, and patient visits within emergency departments.3 During 1992, 1993, and 1994, 93, 94, and 95% of in-scope hospitals participated, respectively.4 – 6 Data were collected by trained hospital staff within each emergency department on a systematic random sample of patient visits, during a randomly assigned 4-week reporting period. Visits were weighted to permit computation of national estimates of emergency and outpatient visits. The data include information on patient demographics and diagnoses. For each visit, up to three diagnoses are recorded. The first diagnosis recorded is the principal diagnosis for the particular visit. Secondary diagnoses may be either additional diagnoses relevant to the visit or preexisting conditions noted during the visit. We examined all three listed diagnoses together. In addition, we analyzed principal diagnoses separately, as a more clearly defined group of gynecologic visits. Diagnoses are coded according to the International Classification of Diseases, ninth revision.7 We examined gynecologic disorders that were listed for conditions of the female genitourinary system, infections of the female genital tract, neoplasms of the female breast and genitourinary system, and ectopic pregnancy. Conditions of pregnancy, other than ectopic pregnancy, were not included. We used only the integers of the codes because of data reliability concerns of the coding beyond the decimal point. We calculated the average annual number of visits and rates of visits per 1000 women, ages 15– 44 years. For the denominators of the rates, we used age, race, and region-specific population estimates of the civilian, noninstitutionalized population of the United States for 1992, 1993, and 1994 (unpublished data from the 1996 round of state population estimates by age and sex, US Bureau of the Census). Race was examined using three categories: white, black, and other (Asian, Pacific Islander and American Indian/Eskimo/Aleut). Because ethnicity was not well reported in these survey data, we chose not to analyze the data by ethnicity. Standard errors and 95% confidence intervals were used to assess sampling variability and measurement error of the survey. Standard errors were computed using SUDAAN (Research Triangle Institute, Research Triangle Park, NC) a software package that accounts for the complex sample design of the survey.8 To identify characteristics of women most likely to seek gynecologic care in emergency departments, we calculated rate ratios (ie, the rate of visits among one group divided by the rate of visits among a comparison group), and we calculated 95% confidence intervals (CIs) to compare rates of visits among different groups of women.
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Table 1. Annual Number and Rate of Emergency Department Visits for Gynecologic Disorders by Demographic Characteristics, Averaged Over a 3-Year Period: United States, 1992–1994 Gynecologic disorders listed as any of 3 diagnoses Rate per 1000 Visits (31000) women Total Age (y) 15–19 20 –24 25–29 30 –34 35–39 40 – 44 Race White Black Other Region† Northeast Midwest South West
95% CI
Gynecologic disorders listed as principal diagnosis Rate per 1000 Visits (31000) women
95% CI
1426
24.3
22.0, 26.6
1119
19.0
17.2, 20.9
343 362 279 216 134 89
40.9 39.7 28.8 19.6 12.5 9.2
34.4, 47.5 34.4, 45.1 24.3, 33.2 15.5, 23.7 9.8, 15.2 6.9, 11.5
278 278 222 167 104 69
33.1 30.5 22.9 15.1 9.7 7.1
27.7, 38.6 25.8, 35.2 19.2, 26.5 11.4, 18.8 7.4, 12.0 5.2, 9.0
875 526 25
18.3 65.1 9.0
15.9, 20.7 56.2, 74.0 4.2, 13.8
689 415 14*
14.4 51.5 5.2*
12.5, 16.3 44.2, 58.8 1.8, 8.7
252 345 576 252
21.6 24.9 28.2 19.7
16.2, 27.0 20.5, 29.4 24.0, 32.3 15.3, 24.2
206 275 459 177
17.7 19.9 22.5 13.9
14.1, 21.3 16.2, 23.6 19.1, 25.8 10.0, 17.8
CI 5 confidence interval. * Estimate does not meet standard of reliability or precision. † Northeast: Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, and Pennsylvania. Midwest: Michigan, Ohio, Illinois, Indiana, Wisconsin, Minnesota, Iowa, Missouri, North Dakota, South Dakota, Nebraska, and Kansas. South: Delaware, Maryland, District of Columbia, Virginia, West Virginia, North Carolina, South Carolina, Georgia, Florida, Kentucky, Tennessee, Alabama, Mississippi, Arkansas, Louisiana, Oklahoma, and Texas. West: Montana, Idaho, Wyoming, Colorado, New Mexico, Arizona, Utah, Nevada, Washington, Oregon, California, Hawaii, and Alaska.10 –12
Results Based on all diagnoses listed for the visits, women of reproductive age made an average of 1.4 million visits each year to emergency departments for gynecologic disorders from 1992 through 1994, for an average annual rate of 24.3 visits per 1000 women (95% CI 22.0, 26.6) (Table 1). The annual rate for the 3 years ranged from 23.3 to 25.1 and was not significantly different from year to year (data not shown). When we examined only the principal diagnoses, the average number of gynecologic visits decreased by 22% to approximately 1.1 million visits per year, for an average annual rate of 19.0 (95% CI 17.2, 20.9) visits per 1000 women (Table 1). Gynecologic visits accounted for 6.3% and 5.0% of all visits made to emergency departments by women ages 15– 44 years, for all diagnoses and for principal diagnoses, respectively. Rates for all diagnoses were highest
Obstetrics & Gynecology
Table 2. Annual Number, Percent, and Rate of Emergency Department Visits for Gynecologic Disorders by Diagnosis, for All Diagnoses and Principal Diagnosis, Averaged Over a 3-Year Period: United States, 1992–1994 Gynecologic disorders listed as any of 3 diagnoses
Gynecologic disorder Total gynecologic disorders PID* Lower genital tract infections† Menstrual disorders‡ Noninflammatory disorders of ovary and fallopian tube§ Noninflammatory vaginal disorders\ Breast disorders¶ Ectopic pregnancy** Other††
Gynecologic disorders listed as principal diagnosis
Visits (31000)
% of total gynecologic visits
Annual rate per 1000 women (95% CI)
24.3 (22.0, 26.6) 5.8 (5.0, 6.6) 5.7 (4.8, 6.6) 2.9 (2.3, 3.5) 2.9 (2.3, 3.5)
1119 258 239 141 93
100.0 23.1 21.4 12.6 8.4
19.0 (17.2, 20.9) 4.4 (3.7, 5.1) 4.1 (3.4, 4.8) 2.4 (1.9, 2.9) 1.6 (1.2, 2.0)
2.4 (1.9, 2.9) 1.3 (0.8, 1.7) 1.1 (0.8, 1.4) 4.2 (3.6, 4.9)
97 71 35 182
8.7 6.4 3.1 16.2
1.7 (1.3, 2.1) 1.2 (0.8, 1.7) 0.6 (0.4, 0.8) 3.1 (2.5, 3.7)
Visits (31000)
% of total gynecologic visits
Annual rate per 1000 women (95% CI)
1426 342 334 170 170
100.0 24.0 23.4 12.0 12.0
141 75 62 247
9.9 5.3 4.3 17.3
CI 5 confidence interval; PID 5 pelvic inflammatory disease; ICD-9 5 International Classification of Diseases, 9th Revision, Clinical Modification.4 * ICD-9 codes 614 – 615. † ICD-9 codes 112, 091– 099, 616; includes sexually transmitted diseases. ‡ ICD-9 code 626. § ICD-9 code 620. \ ICD-9 code 623. ¶ ICD-9 codes 610 – 611. ** ICD-9 code 633. †† ICD-9 codes 174, 179 –184, 217–221, 617– 619, 621– 622, 624 – 625, 627– 629.
among the youngest women and decreased with increasing age (Table 1). Rates were also higher for black women compared with white women or women of races other than black or white. There were no significant differences in the overall rates of visits by geographic region. Rates for principal diagnoses were slightly lower, but followed the same patterns. Examining all diagnoses listed, pelvic inflammatory disease (PID) was the most common gynecologic disorder diagnosed in emergency departments. This diagnosis was noted on approximately 342,000 visits per year, resulting in an average annual rate of 5.8 (95% CI 5.0, 6.6) visits per 1000 women (Table 2). The second most common diagnosis was lower genital tract infections, including sexually transmitted diseases (STDs), with a rate of 5.7 (95% CI 4.8, 6.6) visits per 1000 women. Together, genital tract infections (including PID, lower genital tract infections, and STDs) were diagnosed for 47% of all gynecologic visits to emergency departments. Menstrual disorders, noninflammatory disorders of the ovary and fallopian tube (eg, ovarian cysts), and noninflammatory vaginal disorders (eg, cysts or hemorrhage) were the third, fourth, and fifth most common diagnoses. When examining only principal diagnoses, PID, lower genital tract infections including STDs, and menstrual disorders remained the three most frequent diagnoses (Table 2). We further evaluated the five most common diag-
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noses to identify characteristics of women most likely to seek care for gynecologic disorders in emergency departments (Table 3). For all gynecologic visits combined for all diagnoses listed, younger women (ages 15–24 years) visited emergency departments 2.3 (95% CI 2.0, 2.6) times as frequently as older women (ages 25– 44 years). This association was particularly evident for diagnoses of PID, lower genital tract infections, and noninflammatory vaginal disorders. Black women visited emergency departments 3.6 (95% CI 2.9, 4.3) times
Table 3. Annual Rate Ratios for Gynecologic Visits to Emergency Departments by Age, Race, and Gynecologic Disorder, Averaged Over a 3-Year Period: United States, 1992–1994 Age (15–24 y vs 25– 44 y)
Race (black vs white)
Gynecologic disorder (principal and secondary diagnoses)
Rate ratio
95% CI
Rate ratio
95% CI
Total gynecologic diagnoses PID Lower genital tract infections* Menstrual disorders Noninflammatory disorders of ovary and fallopian tube Noninflammatory vaginal disorders
2.3 2.9 2.9 2.2 1.6
2.0, 2.6 2.1, 3.8 2.1, 3.8 1.4, 3.0 1.1, 2.2
3.6 4.2 6.6 2.9 1.4
2.9, 4.3 2.9, 5.5 4.7, 8.6 1.6, 4.1 0.7, 2.1
3.3
1.9, 4.8
3.7
2.0, 5.4
CI 5 confidence interval; PID 5 pelvic inflammatory disease. * Including sexually transmitted diseases.
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Figure 1. Annual rate ratios for gynecologic visits to emergency departments by race, age, and diagnosis (principal and secondary), averaged over a 3-year period: United States, 1992–1994. Referent group was white women, ages 25– 44 years. *Includes sexually transmitted diseases.
as often as white women for all gynecologic disorders and 6.6 (95% CI 4.7, 8.6) times as often for lower genital tract infections. However, women of races other than black or white visited emergency departments for gynecologic disorders half as often as white women (rate ratio 0.5, 95% CI 0.2, 0.8) (data not shown). Numbers of visits by women of races other than black and white were too few to examine by diagnosis. The only significant difference in rates of visits by diagnosis among the four geographic regions was higher rates of visits for lower genital tract infections in the South (rate ratio 2.3, 95% CI 1.2, 3.4) and the Midwest (rate ratio 2.2, 95% CI 1.1, 3.3) compared with the West (referent group) (data not shown). When examining only the principal diagnoses, rates of visits by age, race, and region decreased slightly compared with the rates for all diagnoses. However, the rate ratios remained similar to those for all diagnoses (data not shown). Next, we examined rates of visits among four age and race groups for the five most frequent diagnoses, for all diagnoses listed (Figure 1). With the exception of noninflammatory disorders of the ovary and fallopian tube, the pattern of risk for each diagnostic group was similar, with younger, black women having the highest risk, followed by older, black women, then younger, white women, and finally older, white women. Rates of visits for PID, lower genital tract infections, and noninflammatory vaginal disorders were 10 to 20 times higher for younger, black women compared with older, white women, although confidence intervals were wide.
Discussion Approximately 1.4 million visits were made to emergency departments for gynecologic disorders annually
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by women of reproductive ages, between 1992 and 1994, based on both principal and secondary diagnoses, and more than 1.1 million gynecologic visits were made, based on principal diagnoses alone. Almost half of these visits were for infectious diseases, including PID, lower genital tract infections, and STDs. Rates of visits among younger, black women were 10 to 20 times higher than among older, white women for diagnoses of PID, lower genital tract infections including STDs, and noninflammatory vaginal disorders. We found significant differences in rates of gynecologic visits by age and race. These differences may be due, in part, to differences in disease incidence among these groups. While we cannot infer disease incidence from the emergency department data, statistics from other sources reveal differences in STD and PID rates by age and racial and ethnic group. For example, in 1995, population-based rates of gonorrhea were three times higher in 15–19 year old women compared with 25–29 year olds.9 Similar findings were reported among women tested for chlamydia in family planning clinics.9 Between 1979 and 1988, hospitalizations for acute PID were highest among women 15–24 years of age, although rates of hospitalizations for chronic PID and of physician visits for PID peaked among women between 20 and 29 years of age.2 In addition, population-based surveillance data find higher rates of STDs among some minority racial and ethnic groups; in 1995, for example, gonorrhea and syphilis rates were 25 and 60 times higher, respectively, among black non-Hispanic women than among white non-Hispanic women.9 Rates of hospitalizations and physician visits for PID were two to three times higher among women of races other than white compared with white women.2 The disparity in rates of gynecologic visits among groups also may reflect varying patterns of seeking
Obstetrics & Gynecology
health care among women of different ages and races. Young age and black race may be risk markers for unmeasured risk factors, including accessibility to and acceptability of primary health care services. To evaluate this possibility, we examined whether the differences in rates by age and race were similar for all visits to emergency departments or a pattern specific to gynecologic visits, under the assumption that rates of visits for all diagnoses would be less influenced by differences in disease incidence. Examining all visits among women between the ages of 15 and 44 years for all diagnoses, younger women had a higher rate of visits than older women (1.4, 95% CI 1.3, 1.4) and black women had a higher rate than white women (1.8, 95% CI 1.6, 2.1) (data not shown). However, these overall differences in seeking emergency department care do not account completely for the variation in rates for gynecologic visits to emergency departments. The rate ratio for younger women compared with older women for gynecologic visits (rate ratio 2.3) was 1.6 times larger than the rate ratio for all visits; similarly the rate ratio for black women compared with white women for gynecologic visits (rate ratio 3.6) was 2.0 times the rate ratio for all visits. Therefore, although these data show high rates of emergency department visits for all diagnoses among younger women and black women, the higher rate ratios specific to gynecologic visits may be due to actual differences in incidence of gynecologic disorders, to increased rates of seeking care in emergency departments specific to gynecologic disorders (over and above that for any diagnosis), or a combination of the two. It is important to note that these data were obtained from emergency department visit records. It was not possible to identify repeat visits for the same condition, nor did we have information on diagnoses made in other health care settings. Therefore, we only were able to estimate numbers and rates of emergency department visits for each condition and cannot infer population incidence or prevalence of disease or risk factors associated with these conditions. However, because the results of this analysis show that emergency departments are an important source of care for gynecologic disorders, especially PID and lower genital tract infections, it is important to include emergency department visits in surveillance efforts for these conditions. This information may be added to numbers and rates from other health services sources (eg, hospital discharge and physician office surveys) to yield more complete surveillance of particular disorders. We analyzed these data by examining principal and total gynecologic diagnoses. Including all diagnoses (principal and secondary) may overestimate the numbers and rates of certain diagnoses if a secondary
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diagnosis was noted as a preexisting condition but was not relevant to the particular visit. Using only the principal diagnosis may lead to an underestimate of those conditions listed as secondary diagnoses, but that were addressed at the visit. There are two reasons that using both principal and secondary diagnoses may be the more appropriate measure for this analysis. First, among visits for which a gynecologic disorder was listed as the secondary diagnosis and a nongynecologic condition was listed as the principal diagnosis, 41% of the gynecologic diagnoses were for acute infectious diseases (ie, PID and lower genital tract infections), which were likely to be relevant to the visit even though they were recorded as the secondary diagnosis. Second, we examined three listed reasons for the visit, coded according to the National Center for Health Statistics’ Reason for Visit Classification Tabular Listing.10 –12 Among visits that had a gynecologic secondary diagnosis, but a nongynecologic principal diagnosis, patients gave a gynecologic reason for 78% of the visits, and this was the primary reason for 65% of these visits. Only 7% of all gynecologic visits, using all diagnoses listed, had neither a principal gynecologic diagnosis nor a principal gynecologic reason for the visit; therefore, using all diagnoses listed may slightly overestimate the number of gynecologic visits made to emergency departments. No attempt has been made to validate any of the diagnoses in these data; therefore, we considered potential sources of misclassification of the most commonly reported diagnoses. In particular, the clinical diagnosis of PID is difficult. A review of 12 published studies indicates that approximately one-third of women with a clinical diagnosis of PID had no laparoscopic evidence of PID.13 This finding suggests that data based on the clinical diagnosis of PID may overestimate the true incidence of PID. However, because an unknown portion of women have asymptomatic PID,13 the reliance on a clinical diagnosis potentially underestimates the incidence of PID as well. Further, to the extent that subgroups of women (eg, young women or women with prior diagnosis of PID) are more likely to have PID diagnosed for a given clinical presentation, the clinical diagnosis of PID could lead to biased as well as imprecise estimates. We are unable to measure the potential impact of bias on our estimates. Misclassification may also have led to underestimates of the number of visits attributed to menstrual disorders, as the category of noninflammatory vaginal disorders included visits listed as “vaginal hemorrhage.” Thus, it is likely that a substantial portion of visits listed as noninflammatory vaginal disorders may be classified more accurately as visits for menstrual disorders. In addition, the number of lower genital tract infections might be slightly overestimated. Because we were
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limited to using only the first three digits of the International Classification of Diseases, ninth revision, codes and because infectious diseases are listed by organism and not by site, we may have included some infections at sites other than the genital tract (eg, gonococcal infection of the eye or joint). However, these infections are rare in women of reproductive age and are unlikely to bias the reported estimates. These findings provide national estimates for numbers and rates of gynecologic visits to emergency departments among women of reproductive age and show that the emergency department is an important source of care for gynecologic conditions. The differences in rates of visits among subgroups of women, especially the 10- to 20-fold greater rates for young, black women, raise serious questions about access to and acceptability of more appropriate primary health care services. In addition, almost half of these gynecologic visits were related to genital tract infections. Because genital tract infections largely are preventable,9,14 –15 half of the burden of disease associated with gynecologic visits to emergency departments also may be preventable.
References 1. Velebil P, Wingo PA, Xia Z, Wilcox LS, Peterson HB. Rate of hospitalization for gynecologic disorders among reproductive-age women in the United States. Obstet Gynecol 1995;86:764 –9. 2. Rolfs RT, Galaid EI, Zaidi AA. Pelvic inflammatory disease: Trends in hospitalizations and office visits, 1979 through 1988. Am J Obstet Gynecol 1992;166:983–90. 3. McCaig LF, McLemore T. Plan and operation of the National Hospital Ambulatory Medical Care Survey. Vital Health Stat 1 1994;34:1–78. 4. McCaig LF. National Hospital Ambulatory Medical Care Survey: 1992 emergency department summary. Advance data from vital and health statistics, No. 245. Hyattsville, Maryland: National Center for Health Statistics, 1994. 5. Stussman BJ. National Hospital Ambulatory Medical Care Survey: 1993 emergency department summary. Advance data from vital and health statistics, No. 271. Hyattsville, Maryland: National Center for Health Statistics, 1996. 6. Stussman BJ. National Hospital Ambulatory Medical Care Survey: 1994 emergency department summary. Advance data from vital and health statistics, No. 275. Hyattsville, Maryland: National Center for Health Statistics, 1996.
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7. International classification of diseases, 9th revision, clinical modification, 4th ed. Publication No. (PHS) 91-1260. Washington, DC: US Department of Health and Human Services, Public Health Service, Health Care Financing Administration, 1991. 8. Shah BV, Barnwell BG, Bieler GS. SUDAAN user’s manual, version 6.4, 2nd ed. Research Triangle Park, North Carolina: Research Triangle Institute, 1996. 9. Division of STD Prevention. Sexually transmitted disease surveillance, 1995. Atlanta, Georgia: US Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, 1996. 10. National Center for Health Statistics. 1992 National Hospital Ambulatory Medical Care Survey. Public use data file documentation. Hyattsville, Maryland: US Department of Health and Human Services, Centers for Disease Control and Prevention, 1992. 11. National Center for Health Statistics. 1993 National Hospital Ambulatory Medical Care Survey. Public use data file documentation. Hyattsville, Maryland: US Department of Health and Human Services, Centers for Disease Control and Prevention, 1993. 12. National Center for Health Statistics. 1994 National Hospital Ambulatory Medical Care Survey. Public use data file documentation. Hyattsville, Maryland: US Department of Health and Human Services, Centers for Disease Control and Prevention, 1994. 13. Cates W Jr, Rolfs R Jr, Aral S. Sexually transmitted diseases, pelvic inflammatory disease, and infertility: An epidemiologic update. Epidemiol Rev 1990;12:199 –220. 14. Eng TR, Butler WT. The hidden epidemic: Confronting sexually transmitted diseases. Washington, DC: National Academy Press, 1997. 15. Piot P, Islam MQ. Sexually transmitted diseases in the 1990s: Global epidemiology and challenges for control. Sex Transm Dis 1994;21 2 Suppl:S7.
Address reprint requests to:
Kathryn M. Curtis, PhD Division of Reproductive Health National Center for Chronic Disease Prevention and Health Promotion 4770 Buford Hwy, NE, MS K-34 Atlanta, GA 30341-3717 E-mail: [email protected]
Received October 21, 1997. Received in revised form January 30, 1998. Accepted February 5, 1998.
Published by Elsevier Science Inc.
Obstetrics & Gynecology
VOL. 91, NO. 6, JUNE 1998
Gynecologic disorders are a common cause of hospitalization among women of reproductive age in the United States.1 Surveys of hospitalizations and physician visits are an important source of surveillance data for gynecologic disorders,2 but until recently such data have not been available for visits made to emergency departments. Therefore, it has not been known what proportion of emergency department visits are due to gynecologic disorders or, consequently, whether the prevalence of acute gynecologic disorders among women of reproductive ages has been underestimated to date. Recently, data from a nationally representative sample of emergency department visits became available for analysis. We used data from the National Hospital Ambulatory Medical Care Survey to estimate the number and rate of visits to emergency departments for gynecologic disorders among women of reproductive age in the United States.
Materials and Methods We used data from the 1992, 1993, and 1994 National Hospital Ambulatory Medical Care Survey, which has been conducted annually by the National Center for Health Statistics since 1992. The survey is a national probability sample of visits to emergency and outpatient departments of nonfederal, short-stay hospitals and is designed to be representative of all visits to emergency and outpatient departments in the United States.3– 6 We used only the emergency department portion of the data for this analysis. A four-stage probability sample design was used for the survey, including primary sampling units (ie, a geographically defined unit, such as a county, group of counties, town,
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minor civil division, or metropolitan statistical area), hospitals within these primary sampling units, emergency departments within hospitals, and patient visits within emergency departments.3 During 1992, 1993, and 1994, 93, 94, and 95% of in-scope hospitals participated, respectively.4 – 6 Data were collected by trained hospital staff within each emergency department on a systematic random sample of patient visits, during a randomly assigned 4-week reporting period. Visits were weighted to permit computation of national estimates of emergency and outpatient visits. The data include information on patient demographics and diagnoses. For each visit, up to three diagnoses are recorded. The first diagnosis recorded is the principal diagnosis for the particular visit. Secondary diagnoses may be either additional diagnoses relevant to the visit or preexisting conditions noted during the visit. We examined all three listed diagnoses together. In addition, we analyzed principal diagnoses separately, as a more clearly defined group of gynecologic visits. Diagnoses are coded according to the International Classification of Diseases, ninth revision.7 We examined gynecologic disorders that were listed for conditions of the female genitourinary system, infections of the female genital tract, neoplasms of the female breast and genitourinary system, and ectopic pregnancy. Conditions of pregnancy, other than ectopic pregnancy, were not included. We used only the integers of the codes because of data reliability concerns of the coding beyond the decimal point. We calculated the average annual number of visits and rates of visits per 1000 women, ages 15– 44 years. For the denominators of the rates, we used age, race, and region-specific population estimates of the civilian, noninstitutionalized population of the United States for 1992, 1993, and 1994 (unpublished data from the 1996 round of state population estimates by age and sex, US Bureau of the Census). Race was examined using three categories: white, black, and other (Asian, Pacific Islander and American Indian/Eskimo/Aleut). Because ethnicity was not well reported in these survey data, we chose not to analyze the data by ethnicity. Standard errors and 95% confidence intervals were used to assess sampling variability and measurement error of the survey. Standard errors were computed using SUDAAN (Research Triangle Institute, Research Triangle Park, NC) a software package that accounts for the complex sample design of the survey.8 To identify characteristics of women most likely to seek gynecologic care in emergency departments, we calculated rate ratios (ie, the rate of visits among one group divided by the rate of visits among a comparison group), and we calculated 95% confidence intervals (CIs) to compare rates of visits among different groups of women.
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Table 1. Annual Number and Rate of Emergency Department Visits for Gynecologic Disorders by Demographic Characteristics, Averaged Over a 3-Year Period: United States, 1992–1994 Gynecologic disorders listed as any of 3 diagnoses Rate per 1000 Visits (31000) women Total Age (y) 15–19 20 –24 25–29 30 –34 35–39 40 – 44 Race White Black Other Region† Northeast Midwest South West
95% CI
Gynecologic disorders listed as principal diagnosis Rate per 1000 Visits (31000) women
95% CI
1426
24.3
22.0, 26.6
1119
19.0
17.2, 20.9
343 362 279 216 134 89
40.9 39.7 28.8 19.6 12.5 9.2
34.4, 47.5 34.4, 45.1 24.3, 33.2 15.5, 23.7 9.8, 15.2 6.9, 11.5
278 278 222 167 104 69
33.1 30.5 22.9 15.1 9.7 7.1
27.7, 38.6 25.8, 35.2 19.2, 26.5 11.4, 18.8 7.4, 12.0 5.2, 9.0
875 526 25
18.3 65.1 9.0
15.9, 20.7 56.2, 74.0 4.2, 13.8
689 415 14*
14.4 51.5 5.2*
12.5, 16.3 44.2, 58.8 1.8, 8.7
252 345 576 252
21.6 24.9 28.2 19.7
16.2, 27.0 20.5, 29.4 24.0, 32.3 15.3, 24.2
206 275 459 177
17.7 19.9 22.5 13.9
14.1, 21.3 16.2, 23.6 19.1, 25.8 10.0, 17.8
CI 5 confidence interval. * Estimate does not meet standard of reliability or precision. † Northeast: Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, and Pennsylvania. Midwest: Michigan, Ohio, Illinois, Indiana, Wisconsin, Minnesota, Iowa, Missouri, North Dakota, South Dakota, Nebraska, and Kansas. South: Delaware, Maryland, District of Columbia, Virginia, West Virginia, North Carolina, South Carolina, Georgia, Florida, Kentucky, Tennessee, Alabama, Mississippi, Arkansas, Louisiana, Oklahoma, and Texas. West: Montana, Idaho, Wyoming, Colorado, New Mexico, Arizona, Utah, Nevada, Washington, Oregon, California, Hawaii, and Alaska.10 –12
Results Based on all diagnoses listed for the visits, women of reproductive age made an average of 1.4 million visits each year to emergency departments for gynecologic disorders from 1992 through 1994, for an average annual rate of 24.3 visits per 1000 women (95% CI 22.0, 26.6) (Table 1). The annual rate for the 3 years ranged from 23.3 to 25.1 and was not significantly different from year to year (data not shown). When we examined only the principal diagnoses, the average number of gynecologic visits decreased by 22% to approximately 1.1 million visits per year, for an average annual rate of 19.0 (95% CI 17.2, 20.9) visits per 1000 women (Table 1). Gynecologic visits accounted for 6.3% and 5.0% of all visits made to emergency departments by women ages 15– 44 years, for all diagnoses and for principal diagnoses, respectively. Rates for all diagnoses were highest
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Table 2. Annual Number, Percent, and Rate of Emergency Department Visits for Gynecologic Disorders by Diagnosis, for All Diagnoses and Principal Diagnosis, Averaged Over a 3-Year Period: United States, 1992–1994 Gynecologic disorders listed as any of 3 diagnoses
Gynecologic disorder Total gynecologic disorders PID* Lower genital tract infections† Menstrual disorders‡ Noninflammatory disorders of ovary and fallopian tube§ Noninflammatory vaginal disorders\ Breast disorders¶ Ectopic pregnancy** Other††
Gynecologic disorders listed as principal diagnosis
Visits (31000)
% of total gynecologic visits
Annual rate per 1000 women (95% CI)
24.3 (22.0, 26.6) 5.8 (5.0, 6.6) 5.7 (4.8, 6.6) 2.9 (2.3, 3.5) 2.9 (2.3, 3.5)
1119 258 239 141 93
100.0 23.1 21.4 12.6 8.4
19.0 (17.2, 20.9) 4.4 (3.7, 5.1) 4.1 (3.4, 4.8) 2.4 (1.9, 2.9) 1.6 (1.2, 2.0)
2.4 (1.9, 2.9) 1.3 (0.8, 1.7) 1.1 (0.8, 1.4) 4.2 (3.6, 4.9)
97 71 35 182
8.7 6.4 3.1 16.2
1.7 (1.3, 2.1) 1.2 (0.8, 1.7) 0.6 (0.4, 0.8) 3.1 (2.5, 3.7)
Visits (31000)
% of total gynecologic visits
Annual rate per 1000 women (95% CI)
1426 342 334 170 170
100.0 24.0 23.4 12.0 12.0
141 75 62 247
9.9 5.3 4.3 17.3
CI 5 confidence interval; PID 5 pelvic inflammatory disease; ICD-9 5 International Classification of Diseases, 9th Revision, Clinical Modification.4 * ICD-9 codes 614 – 615. † ICD-9 codes 112, 091– 099, 616; includes sexually transmitted diseases. ‡ ICD-9 code 626. § ICD-9 code 620. \ ICD-9 code 623. ¶ ICD-9 codes 610 – 611. ** ICD-9 code 633. †† ICD-9 codes 174, 179 –184, 217–221, 617– 619, 621– 622, 624 – 625, 627– 629.
among the youngest women and decreased with increasing age (Table 1). Rates were also higher for black women compared with white women or women of races other than black or white. There were no significant differences in the overall rates of visits by geographic region. Rates for principal diagnoses were slightly lower, but followed the same patterns. Examining all diagnoses listed, pelvic inflammatory disease (PID) was the most common gynecologic disorder diagnosed in emergency departments. This diagnosis was noted on approximately 342,000 visits per year, resulting in an average annual rate of 5.8 (95% CI 5.0, 6.6) visits per 1000 women (Table 2). The second most common diagnosis was lower genital tract infections, including sexually transmitted diseases (STDs), with a rate of 5.7 (95% CI 4.8, 6.6) visits per 1000 women. Together, genital tract infections (including PID, lower genital tract infections, and STDs) were diagnosed for 47% of all gynecologic visits to emergency departments. Menstrual disorders, noninflammatory disorders of the ovary and fallopian tube (eg, ovarian cysts), and noninflammatory vaginal disorders (eg, cysts or hemorrhage) were the third, fourth, and fifth most common diagnoses. When examining only principal diagnoses, PID, lower genital tract infections including STDs, and menstrual disorders remained the three most frequent diagnoses (Table 2). We further evaluated the five most common diag-
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noses to identify characteristics of women most likely to seek care for gynecologic disorders in emergency departments (Table 3). For all gynecologic visits combined for all diagnoses listed, younger women (ages 15–24 years) visited emergency departments 2.3 (95% CI 2.0, 2.6) times as frequently as older women (ages 25– 44 years). This association was particularly evident for diagnoses of PID, lower genital tract infections, and noninflammatory vaginal disorders. Black women visited emergency departments 3.6 (95% CI 2.9, 4.3) times
Table 3. Annual Rate Ratios for Gynecologic Visits to Emergency Departments by Age, Race, and Gynecologic Disorder, Averaged Over a 3-Year Period: United States, 1992–1994 Age (15–24 y vs 25– 44 y)
Race (black vs white)
Gynecologic disorder (principal and secondary diagnoses)
Rate ratio
95% CI
Rate ratio
95% CI
Total gynecologic diagnoses PID Lower genital tract infections* Menstrual disorders Noninflammatory disorders of ovary and fallopian tube Noninflammatory vaginal disorders
2.3 2.9 2.9 2.2 1.6
2.0, 2.6 2.1, 3.8 2.1, 3.8 1.4, 3.0 1.1, 2.2
3.6 4.2 6.6 2.9 1.4
2.9, 4.3 2.9, 5.5 4.7, 8.6 1.6, 4.1 0.7, 2.1
3.3
1.9, 4.8
3.7
2.0, 5.4
CI 5 confidence interval; PID 5 pelvic inflammatory disease. * Including sexually transmitted diseases.
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Figure 1. Annual rate ratios for gynecologic visits to emergency departments by race, age, and diagnosis (principal and secondary), averaged over a 3-year period: United States, 1992–1994. Referent group was white women, ages 25– 44 years. *Includes sexually transmitted diseases.
as often as white women for all gynecologic disorders and 6.6 (95% CI 4.7, 8.6) times as often for lower genital tract infections. However, women of races other than black or white visited emergency departments for gynecologic disorders half as often as white women (rate ratio 0.5, 95% CI 0.2, 0.8) (data not shown). Numbers of visits by women of races other than black and white were too few to examine by diagnosis. The only significant difference in rates of visits by diagnosis among the four geographic regions was higher rates of visits for lower genital tract infections in the South (rate ratio 2.3, 95% CI 1.2, 3.4) and the Midwest (rate ratio 2.2, 95% CI 1.1, 3.3) compared with the West (referent group) (data not shown). When examining only the principal diagnoses, rates of visits by age, race, and region decreased slightly compared with the rates for all diagnoses. However, the rate ratios remained similar to those for all diagnoses (data not shown). Next, we examined rates of visits among four age and race groups for the five most frequent diagnoses, for all diagnoses listed (Figure 1). With the exception of noninflammatory disorders of the ovary and fallopian tube, the pattern of risk for each diagnostic group was similar, with younger, black women having the highest risk, followed by older, black women, then younger, white women, and finally older, white women. Rates of visits for PID, lower genital tract infections, and noninflammatory vaginal disorders were 10 to 20 times higher for younger, black women compared with older, white women, although confidence intervals were wide.
Discussion Approximately 1.4 million visits were made to emergency departments for gynecologic disorders annually
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by women of reproductive ages, between 1992 and 1994, based on both principal and secondary diagnoses, and more than 1.1 million gynecologic visits were made, based on principal diagnoses alone. Almost half of these visits were for infectious diseases, including PID, lower genital tract infections, and STDs. Rates of visits among younger, black women were 10 to 20 times higher than among older, white women for diagnoses of PID, lower genital tract infections including STDs, and noninflammatory vaginal disorders. We found significant differences in rates of gynecologic visits by age and race. These differences may be due, in part, to differences in disease incidence among these groups. While we cannot infer disease incidence from the emergency department data, statistics from other sources reveal differences in STD and PID rates by age and racial and ethnic group. For example, in 1995, population-based rates of gonorrhea were three times higher in 15–19 year old women compared with 25–29 year olds.9 Similar findings were reported among women tested for chlamydia in family planning clinics.9 Between 1979 and 1988, hospitalizations for acute PID were highest among women 15–24 years of age, although rates of hospitalizations for chronic PID and of physician visits for PID peaked among women between 20 and 29 years of age.2 In addition, population-based surveillance data find higher rates of STDs among some minority racial and ethnic groups; in 1995, for example, gonorrhea and syphilis rates were 25 and 60 times higher, respectively, among black non-Hispanic women than among white non-Hispanic women.9 Rates of hospitalizations and physician visits for PID were two to three times higher among women of races other than white compared with white women.2 The disparity in rates of gynecologic visits among groups also may reflect varying patterns of seeking
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health care among women of different ages and races. Young age and black race may be risk markers for unmeasured risk factors, including accessibility to and acceptability of primary health care services. To evaluate this possibility, we examined whether the differences in rates by age and race were similar for all visits to emergency departments or a pattern specific to gynecologic visits, under the assumption that rates of visits for all diagnoses would be less influenced by differences in disease incidence. Examining all visits among women between the ages of 15 and 44 years for all diagnoses, younger women had a higher rate of visits than older women (1.4, 95% CI 1.3, 1.4) and black women had a higher rate than white women (1.8, 95% CI 1.6, 2.1) (data not shown). However, these overall differences in seeking emergency department care do not account completely for the variation in rates for gynecologic visits to emergency departments. The rate ratio for younger women compared with older women for gynecologic visits (rate ratio 2.3) was 1.6 times larger than the rate ratio for all visits; similarly the rate ratio for black women compared with white women for gynecologic visits (rate ratio 3.6) was 2.0 times the rate ratio for all visits. Therefore, although these data show high rates of emergency department visits for all diagnoses among younger women and black women, the higher rate ratios specific to gynecologic visits may be due to actual differences in incidence of gynecologic disorders, to increased rates of seeking care in emergency departments specific to gynecologic disorders (over and above that for any diagnosis), or a combination of the two. It is important to note that these data were obtained from emergency department visit records. It was not possible to identify repeat visits for the same condition, nor did we have information on diagnoses made in other health care settings. Therefore, we only were able to estimate numbers and rates of emergency department visits for each condition and cannot infer population incidence or prevalence of disease or risk factors associated with these conditions. However, because the results of this analysis show that emergency departments are an important source of care for gynecologic disorders, especially PID and lower genital tract infections, it is important to include emergency department visits in surveillance efforts for these conditions. This information may be added to numbers and rates from other health services sources (eg, hospital discharge and physician office surveys) to yield more complete surveillance of particular disorders. We analyzed these data by examining principal and total gynecologic diagnoses. Including all diagnoses (principal and secondary) may overestimate the numbers and rates of certain diagnoses if a secondary
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diagnosis was noted as a preexisting condition but was not relevant to the particular visit. Using only the principal diagnosis may lead to an underestimate of those conditions listed as secondary diagnoses, but that were addressed at the visit. There are two reasons that using both principal and secondary diagnoses may be the more appropriate measure for this analysis. First, among visits for which a gynecologic disorder was listed as the secondary diagnosis and a nongynecologic condition was listed as the principal diagnosis, 41% of the gynecologic diagnoses were for acute infectious diseases (ie, PID and lower genital tract infections), which were likely to be relevant to the visit even though they were recorded as the secondary diagnosis. Second, we examined three listed reasons for the visit, coded according to the National Center for Health Statistics’ Reason for Visit Classification Tabular Listing.10 –12 Among visits that had a gynecologic secondary diagnosis, but a nongynecologic principal diagnosis, patients gave a gynecologic reason for 78% of the visits, and this was the primary reason for 65% of these visits. Only 7% of all gynecologic visits, using all diagnoses listed, had neither a principal gynecologic diagnosis nor a principal gynecologic reason for the visit; therefore, using all diagnoses listed may slightly overestimate the number of gynecologic visits made to emergency departments. No attempt has been made to validate any of the diagnoses in these data; therefore, we considered potential sources of misclassification of the most commonly reported diagnoses. In particular, the clinical diagnosis of PID is difficult. A review of 12 published studies indicates that approximately one-third of women with a clinical diagnosis of PID had no laparoscopic evidence of PID.13 This finding suggests that data based on the clinical diagnosis of PID may overestimate the true incidence of PID. However, because an unknown portion of women have asymptomatic PID,13 the reliance on a clinical diagnosis potentially underestimates the incidence of PID as well. Further, to the extent that subgroups of women (eg, young women or women with prior diagnosis of PID) are more likely to have PID diagnosed for a given clinical presentation, the clinical diagnosis of PID could lead to biased as well as imprecise estimates. We are unable to measure the potential impact of bias on our estimates. Misclassification may also have led to underestimates of the number of visits attributed to menstrual disorders, as the category of noninflammatory vaginal disorders included visits listed as “vaginal hemorrhage.” Thus, it is likely that a substantial portion of visits listed as noninflammatory vaginal disorders may be classified more accurately as visits for menstrual disorders. In addition, the number of lower genital tract infections might be slightly overestimated. Because we were
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limited to using only the first three digits of the International Classification of Diseases, ninth revision, codes and because infectious diseases are listed by organism and not by site, we may have included some infections at sites other than the genital tract (eg, gonococcal infection of the eye or joint). However, these infections are rare in women of reproductive age and are unlikely to bias the reported estimates. These findings provide national estimates for numbers and rates of gynecologic visits to emergency departments among women of reproductive age and show that the emergency department is an important source of care for gynecologic conditions. The differences in rates of visits among subgroups of women, especially the 10- to 20-fold greater rates for young, black women, raise serious questions about access to and acceptability of more appropriate primary health care services. In addition, almost half of these gynecologic visits were related to genital tract infections. Because genital tract infections largely are preventable,9,14 –15 half of the burden of disease associated with gynecologic visits to emergency departments also may be preventable.
References 1. Velebil P, Wingo PA, Xia Z, Wilcox LS, Peterson HB. Rate of hospitalization for gynecologic disorders among reproductive-age women in the United States. Obstet Gynecol 1995;86:764 –9. 2. Rolfs RT, Galaid EI, Zaidi AA. Pelvic inflammatory disease: Trends in hospitalizations and office visits, 1979 through 1988. Am J Obstet Gynecol 1992;166:983–90. 3. McCaig LF, McLemore T. Plan and operation of the National Hospital Ambulatory Medical Care Survey. Vital Health Stat 1 1994;34:1–78. 4. McCaig LF. National Hospital Ambulatory Medical Care Survey: 1992 emergency department summary. Advance data from vital and health statistics, No. 245. Hyattsville, Maryland: National Center for Health Statistics, 1994. 5. Stussman BJ. National Hospital Ambulatory Medical Care Survey: 1993 emergency department summary. Advance data from vital and health statistics, No. 271. Hyattsville, Maryland: National Center for Health Statistics, 1996. 6. Stussman BJ. National Hospital Ambulatory Medical Care Survey: 1994 emergency department summary. Advance data from vital and health statistics, No. 275. Hyattsville, Maryland: National Center for Health Statistics, 1996.
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7. International classification of diseases, 9th revision, clinical modification, 4th ed. Publication No. (PHS) 91-1260. Washington, DC: US Department of Health and Human Services, Public Health Service, Health Care Financing Administration, 1991. 8. Shah BV, Barnwell BG, Bieler GS. SUDAAN user’s manual, version 6.4, 2nd ed. Research Triangle Park, North Carolina: Research Triangle Institute, 1996. 9. Division of STD Prevention. Sexually transmitted disease surveillance, 1995. Atlanta, Georgia: US Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, 1996. 10. National Center for Health Statistics. 1992 National Hospital Ambulatory Medical Care Survey. Public use data file documentation. Hyattsville, Maryland: US Department of Health and Human Services, Centers for Disease Control and Prevention, 1992. 11. National Center for Health Statistics. 1993 National Hospital Ambulatory Medical Care Survey. Public use data file documentation. Hyattsville, Maryland: US Department of Health and Human Services, Centers for Disease Control and Prevention, 1993. 12. National Center for Health Statistics. 1994 National Hospital Ambulatory Medical Care Survey. Public use data file documentation. Hyattsville, Maryland: US Department of Health and Human Services, Centers for Disease Control and Prevention, 1994. 13. Cates W Jr, Rolfs R Jr, Aral S. Sexually transmitted diseases, pelvic inflammatory disease, and infertility: An epidemiologic update. Epidemiol Rev 1990;12:199 –220. 14. Eng TR, Butler WT. The hidden epidemic: Confronting sexually transmitted diseases. Washington, DC: National Academy Press, 1997. 15. Piot P, Islam MQ. Sexually transmitted diseases in the 1990s: Global epidemiology and challenges for control. Sex Transm Dis 1994;21 2 Suppl:S7.
Address reprint requests to:
Kathryn M. Curtis, PhD Division of Reproductive Health National Center for Chronic Disease Prevention and Health Promotion 4770 Buford Hwy, NE, MS K-34 Atlanta, GA 30341-3717 E-mail: [email protected]
Received October 21, 1997. Received in revised form January 30, 1998. Accepted February 5, 1998.
Published by Elsevier Science Inc.
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