Epidemiology of extrapulmonary tuberculosis. A comparative analysis with pre-AIDS era

Abstract

To study the changes in the epidemiology of extrapulmonary tuberculosis in Tennessee, we compared the 454 cases of extrapulmonary tuberculosis reported between 1977 and 1981 with 356 cases encountered between 1982 and 1986. The data were analyzed by age, sex, race and site of the disease which were compared with the national statistics during the periods. We observed that 11.3 percent of the total TB cases were extrapulmonary. Unlike national statistics, the proportion of extrapulmonary tuberculosis had remained unchanged between the two study periods. Except for a significant decline (p less than 0.001) in genitourinary tuberculosis, the incidence of other extrapulmonary TB had remained the same. The higher incidences of lymphatic, miliary, and meningeal TB were noted in nonwhites, particularly in the younger population, during both study periods. While the national trend showed a steady increase in the percentage of extrapulmonary TB cases, there was no change in Tennessee. The reason for a continued decline of GU TB remains unclear. Although AIDS may have contributed toward the increase nationally, fewer cases of AIDS in the state have not influenced the proportion of extrapulmonary TB. Awareness of such regional differences in the epidemiology of TB, and the impact of HIV infection, will be very useful to physicians and other health care providers involved in the diagnosis, treatment, and prevention of tuberculosis.