Drug-resistant tuberculosis: factors associated with rise in resistance in an HIV-infected urban population

Our objective was to characterize the population with tuberculosis (TB) and to identify factors predictive of resistance to anti-TB agents in an area of high prevalence of human immunodeficiency virus infection. We reviewed microbiology and clinical records from 1988 to 1991 at Beth Israel Medical Center, New York City, for patients with culture-proved TB and analyzed the frequency of resistance to anti-TB agents with respect to demographic and clinical variables. Of 360 patients with TB, 17.5% had drug-resistant isolates. Of the 333 patients on whom the information was available, 72% reported HIV risk factors, 54% injectable drug use, and nearly one-third homelessness. The majority (56%) had documented HIV infection. Between 1988 and 1991, acquired resistance to isoniazid (INH) alone rose from 5% to 21% and initial resistance to INH alone rose from 0% to 19%. Drug resistance was more likely in previously treated patients; 61% of the previously treated patients admitted noncompliance with therapy. Cavitary lung disease was the strongest predictor of acquired drug resistance. Initial drug resistance was more likely in patients with HIV infection. Among persons with HIV infection, none of the analyzed factors was found to be predictive of drug resistance. Noncompliance with therapy and the HIV epidemic played a major role in the rise of drug resistance in our population. HIV infection confounds the epidemiologic factors that might otherwise allow clinical prediction of resistance.