• Meredith S Shiels, Stephen R Cole, Joan S Chmiel, Joseph Margolick, Jeremy Martinson, Zuo-Feng Zhang, and Lisa P Jacobson.
• Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA. shielsms@mail.nih.gov
• J Clin Epidemiol. 2010 Apr 1; 63 (4): 459-67.

ObjectiveTo compare three ad hoc methods to estimate the marginal hazard of incident cancer acquired immune deficiency syndrome (AIDS) in a highly active antiretroviral therapy (1996-2006) relative to a monotherapy/combination therapy (1990-1996) calendar period, accounting for other AIDS events and deaths as competing risks.Study Design And SettingAmong 1,911 human immunodeficiency virus (HIV)-positive men from the Multicenter AIDS Cohort Study, 228 developed cancer AIDS and 745 developed competing risks in 14,202 person-years from 1990 to 2006. Method 1 censored competing risks at the time they occurred, method 2 excluded competing risks, and method 3 censored competing risks at the date of analysis.ResultsThe age, race, and infection duration adjusted hazard ratios (HRs) for cancer AIDS were similar for all methods (HR approximately 0.15). We estimated bias and confidence interval coverage of each method with Monte Carlo simulation. On average, across 24 scenarios, method 1 produced less-biased estimates than methods 2 or 3.ConclusionsWhen competing risks are independent of the event of interest, only method 1 produced unbiased estimates of the marginal HR, although independence cannot be verified from the data. When competing risks are dependent, method 1 generally produced the least-biased estimates of the marginal HR for the scenarios explored; however, alternative methods may be preferred.Copyright 2010 Elsevier Inc. All rights reserved.

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