AN EPIDEMIOLOGIC ANALYSIS OF MYCOBACTERIUM-AVIUM COMPLEX DISEASE IN HOMOSEXUAL MEN INFECTED WITH HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1

Cofactors associated with the Mycobacterium avium complex (MAC) diseas e and its prognosis in incident cases of AIDS in homosexuals were stud ied. We compared 51 men in whom MAC disease developed as the initial A IDS-defining illness (termed AIDS illness hereafter); 157 men who had MAC disease subsequent to another AIDS illness; and 884 men who had on ly non-MAC AIDS illnesses. MAC disease was the initially diagnosed AID S illness more often in Baltimore (6.9%) and Los Angeles (5.6%) than i n Chicago (2.6%) and Pittsburgh (0) (P <.01), MAC disease also was a m ore common subsequent AIDS illness in Baltimore (14.3%) and Los Angele s (22.4%) than in Chicago (8.5%) and Pittsburgh (6.5%) (P <.0001), Pro phylaxis for Pneumocystis carinii infection increased the occurrence o f MAC disease as the initial AIDS illness (from 2.3% to 12.5%; P <.000 1). A low white blood cell(WBC) count was slightly more predictive of MAC disease than was a low CD4(+) cell count. At 0-6, 7-12, and 13-18 months before diagnosis, the WBC cell counts of 75.0%, 61.1%, and 50.0 %, respectively, of those with MAC disease as the initial AIDS illness were less than or equal to 3,400/mu L. Men in whom cytomegalovirus di sease developed were at higher risk for subsequent MAC disease (relati ve hazard = 2.65; P <.0001), MAC disease also increased the risk for s ubsequent cytomegalovirus disease (relative hazard = 3.96; P <.0001).