Hysterectomy among Women of Reproductive Age, United States, Update for 1981-1982
Kathleen L. Irwin, M.D. Herbert B. Peterson, M.D. Epidemiologic Studies Branch Joyce M. Hughes Sara W. Gill Research and Statistics Branch Division of Reproductive Health Center for Health Promotion and Education
Nearly 5 million American women underwent hysterectomy in the last decade, making this procedure one of the most frequently performed operations for women of reproductive age (1) and an important public health concern. Since 1970, CDC has provided epidemiologic surveillance of hysterectomies performed on women 15-44 years of age; summary data have been previously published (2-4). This report provides an analysis of the influence of age, race, geographic region, and surgical approach on hysterectomy rates for 1981-1982 and updates the analysis of hysterectomy rates for 1970-1980 (4). This previous analysis showed that the nationwide hysterectomy rate declined from 1975 to 1980 among women of reproductive age. The current analysis, however, indicates that the noted decline may have begun to plateau, although rates in 1982 were the lowest since 1970. Major differences in rates by region and age and in the percentage of hysterectomies performed by the vaginal route have persisted. In 1982, for the first time since surveillance began in 1970, blacks had a lower hysterectomy rate than whites. Methods
The methods of this study have been described in detail elsewhere (2). In brief, the data were collected by the National Center for Health Statistics (NCHS) as part of the ongoing National Hospital Discharge Survey (NHDS), which estimates the number and characteristics of patients admitted to U.S. non-Federal, short-stay hospitals for surgical procedures, disease, or injury. For this and previous reports, only total and subtotal hysterectomies with or without concomitant oophorectomy were included; radical hysterectomies and pelvic exenteration were excluded.
The population estimates used in computing rates for this report were based on data from current population surveys conducted by the U.S. Bureau of the Census. Data on race were grouped into the categories of white and black, the latter category including all races other than white. In 1981, NCHS did not report the percentage of hysterectomies classified as unknown for race. Prior to release of data, unknowns were redistributed between the categories of white and black based on the distribution of race in the geographic area of the hospital and on information on the diagnoses and expected source of payment indicated on those records for which race was reported (5). This was not done for the 1982 data. In 1982, as for all previous years except 1981, CDC redistributed the 9% of hysterectomies classified as unknown for race according to the percentage of knowns for race in that year (2-4). Results
In the period 1970-1982, an estimated 5,170,000 women 15-44 years of age underwent hysterectomy in U.S. non-Federal, short-stay hospitals. The number of hysterectomies increased from a low of 306,000 in 1970 to a high of 442,000 in 1977 and then declined to 421,000 in 1981 and 407,000 in 1982 (Figure 1).
The hysterectomy rate in 1981 was 7.9/1,000 women ages 15-44 years and in 1982 was 7.5, the lowest rate since 1970 (Figure 2). From 1970 to 1981, the hysterectomy rate for black women was higher than that for white women. However, in 1982, for the first time since surveillance began in 1970, the rate for black women, 6.7/1,000, was less than the 7.7 rate for white women. From 1975 to 1982, the hysterectomy rate declined 14% for whites and 34% for blacks. In the period 1981-1982, the average age at the time of hysterectomy was 35 years for both blacks and whites.
For the period 1981-1982, as in previous years, the highest hysterectomy rate for women of reproductive age was for the 35- to 44-year age group, and the lowest was for the 15- to 24-year age group (Figure 3). In 1982, approximately one in 63 women 35-44 years of age underwent a hysterectomy. This is a conservative estimate because women who had had hysterectomies in previous years were not removed from the denominator.
Hysterectomy rates also varied by region during this period (Figure 4). As in previous years, women in the Northeast had the lowest hysterectomy rate of the four regions, whereas women in the South had the highest rate. The hysterectomy rate for women in the South was 2.5 times that for women in the Northeast. The average age at time of hysterectomy was similar in all geographic areas, ranging from 34.2 years in the South to 36.6 years in the Northeast.
In 1981 and 1982, 27% and 24%, respectively, of all hysterectomies were performed by the vaginal route (Figure 5). In 1970, the percentage of vaginal hysterectomies among whites (27%) was similar to that among blacks (25%). By 1982, however, the percentage among whites (26%) was twice that among blacks (13%). In the period 1981-1982, there were substantial differences in the percentage of vaginal hysterectomies by region: 14% in the Northeast, 23% in the North Central region, 27% in the South, and 33% in the West. Discussion
Analysis of NHDS data on hysterectomy among women of reproductive age shows that the decline in the nationwide rate noted from 1975 to 1980 may have begun to plateau in the period 1981-1982. However, since the rates for 1981 and 1982 represent only two annual estimates among the 13 annual estimates that have now been reported, it cannot be ascertained if these new estimates represent the beginning of a plateau in rates or a continuation of the previously noted decline.
These results probably underestimate the true rates of hysterectomy because women undergoing hysterectomy in Federally operated hospitals are not included in the NHDS data, and women ages 15-44 years who had already had a hysterectomy were not excluded from the denominator. The degree to which these rates are underestimated is probably greater in those areas and for those ages that had relatively higher rates of hysterectomy. However, a study that adjusted the 1971-1978 hysterectomy rates for the number of U.S. women ages 15-44 years who had already had a hysterectomy showed that trends in rates were similar to those reported for this period in previous CDC surgical sterilization surveillance reports (6).
During 1979-1980, differences in hysterectomy rates between blacks and whites declined noticeably. In 1981, however, the rates of blacks and whites diverged, only to converge again in 1982. The instability of race-specific rates may be due, in part, to the two different methods of imputing unknowns for race in 1981 and 1982. Similarly, the divergence in percentages of vaginal hysterectomies between blacks and whites that was seen in the period 1981-1982 may be due to unstable race-specific hysterectomy rates, which, in turn, may be due either to the different methods of redistributing unknowns for race or to the small absolute number of hysterectomies among blacks surveyed.
Variations in hysterectomy rates by region have persisted since 1970 (2-4). Factors related to both patients and physicians may contribute to these regional differences. Patient-related factors may include regional differences in the incidence of gynecologic conditions and in general attitudes toward surgery or sterilization during the reproductive years (7). Physician-related factors may include regional differences in trends in training and practice (8,9).
In conclusion, while 1982 national and regional hysterectomy rates reached their lowest level since 1970, those for the period 1981-1982 may represent either the beginning of a plateau or a continued decline in rates since 1975. Further surveillance of hysterectomy rates among women of reproductive age in U.S. non-Federal, short-stay hospitals will determine the direction of these trends in the early 1980s.
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