Risk of anal cancer in HIV-infected patients and HIV-uninfected controls in North America

Methods We conducted a cohort study involving 12 cohorts from North America followed between 1996 and 2007. Anal cancer incidence rates were compared between HIV+ men who have sex with men (MSM), HIV+ non-MSM (including women), and HIVindividuals. We calculated rate ratios (RRs) using multivariable Poisson regression with adjustment for age, sex, race/ethnicity (26% imputed), and calendar era. We next determined whether the adjusted RR for HIV+ compared with HIVcontrols has changed over time. Since only a subset of cohorts contributed HIVcontrols, we also computed ageand sexand race-standardized incidence ratios (SIR) using national U.S. SEER rates.