DISSEMINATED MYCOBACTERIUM-AVIUM COMPLEX DISEASE IN THE SWISS HIV COHORT STUDY - INCREASING INCIDENCE, UNCHANGED PROGNOSIS

Objectives: Disseminated disease due to Mycobacterium avium complex (M AC) bacteria is thought to occur less frequently in Europe than in the USA. This study investigated rime trends in the occurrence of, and su rvival with, disseminated MAC disease in the Swiss HIV Cohort Study (S HCS). Design, setting and participants: The SHCS participants who were free of disseminated MAC disease at registration were stratified by c alendar period (1987-1989, 1990-1992, 1993-1995) in which the first re corded CD4 count was 0-49, 50-99, or 100-199 x 10(6)/l. Kaplan-Meier e stimates of the probability of developing and surviving disseminated M AC disease were calculated for these nine independent groups. Multivar iate analyses were performed using Cox proportional hazards regression . Results: The analysis was based on 6052 participants enrolled betwee n January 1987 and December 1995 and 202 incident episodes of dissemin ated MAC disease recorded during a mean follow-up time of 3.5 years. T he cumulative probability of MAC disease at 2 years in individuals wit h CD4 counts of 0-49 x 10(6)/l; in 1987-1989 was 9.8% [95% confidence interval (CI) 4.4-15.2%], increasing to 29.8% (95% CI, 20.8-38.8%) in 1993-1995. Amongst those with CD4 counts from 50-99 x 10(6)/l these pr obabilities were 11.9% (95% CI, 5.9-17.8%), and 21.6% (95% CI, 13.9-29 .2%), respectively. After adjusting for CD4 count the relative hazard of developing disseminated MAC disease in 1993-1995, compared with 198 7-1989, was 1.37 (95% CI, 0.92-2.04). Median survival following diagno sis was 7.9 months with no improvement over time. Conclusions: The inc idence of disseminated MAC disease among SHCS participants has increas ed over time. More profound levels of immunosuppression amongst recent study entrants were found to explain this. When compared with US coho rts studied over the same calendar period the incidence of disseminate d MAC disease in the SHCS appears to be lower. These findings are cons istent with a secular effect of a more mature HIV epidemic in the US b ut direct comparison between the SHCS and a similar prospective cohort in the US should be undertaken to clarify this issue.