Competing risk adjustment reduces overestimation of opportunistic infection rates in AIDS

To illustrate the importance of adjusting the estimates of cumulative incid ence of acquired immunodeficiency syndrome (AIDS) related illnesses for com peting risk of other causes of death, we compared unadjusted and adjusted ( for competing events) incidence estimates for four AIDS illnesses: pneumocy stis cavinii pneumonia (PCP), mycobacterium avium complex (MAC), cytomegalo virus (CMV), and esophageal candidiases. The study population was patients followed by the Johns Hopkins Hospital AIDS Service between 1989 to 1995. R atios of 4 year unadjusted incidence estimates to 4 year adjusted incidence estimates for the four diseases ranged from 1.38 to 1.86, corresponding to cumulative death rates of 61% to 69%. For CMV, the ratios of 4 year unadju sted to adjusted incidence estimates for five groups of patients ranged fro m 1.5 to 2.33, corresponding to cumulative death rates of 48% to 78%. We co nclude that ignoring the competing risk of death can result in substantial overestimation of disease occurrence, which may give misleading results in estimating and comparing the occurrence of a disease of interest. (C) 2000 Elsevier Science Inc. All rights reserved.