Incidence of Kaposi sarcoma in HIV-infected patients receiving antiretroviral therapy: A prospective multicohort study from southern Africa.

Abstract

1589 Background: The incidence of Kaposi sarcoma (KS) is high in Southern Africa: KS is the most common cancer in HIV-infected persons. Data on KS in patients receiving antiretroviral therapy (ART) are, however, scarce in Africa. Within the framework of a large multi-cohort project, the International epidemiologic Database to Evaluate AIDS (IeDEA), we studied the incidence and risk factors for the development of KS in HIV-infected patients starting ART in Southern Africa. Methods: We analyzed prospectively collected data of HIV-infected patients who started ART with three antiretroviral drugs from at least two classes. Prevalent KS cases diagnosed before or at start of ART were excluded. Incidence rates and 95% confidence intervals (CI) were calculated based on the Poisson distribution; risk factors were estimated using crude and adjusted Cox models. Hazard ratios (HR) with 95% CI and medians with interquartile ranges (IQR) are presented. Results: 185,924 patients from 7 cohort studies in Botswana, Mozambique, South Africa, Zambia, Zimbabwe with 376,630 person-years of follow-up were included. At start of ART median age was 34 years (IQR 28–41) and median CD4 cell count 145 cells/µl (IQR 73-225). 61% of patients were female. A total of 601 incident KS cases were recorded. The incidence for KS in patients on ART was 160 (95% CI 147-173) per 100,000 person-years. The risk for KS increased with age. Adjusting for age, gender, WHO stage and CD4 cell count adults >40 years had a more than ten-fold increased risk for developing KS compared to infants (HR 11.8, 95% CI 3.0-46.2); men were more likely to develop KS compared to women (HR 1.4, 95% CI 1.1-1.7) and the risk to develop KS was increased in patients with AIDS at start ART (WHO stage IV vs. I: HR 2.2, 95% CI 1.6-3.1). Conclusions: In Southern African countries with a high prevalence of HHV-8 the risk to develop KS in HIV infected patients receiving ART increases steeply with age and is higher in patients with more advanced HIV infection.