Comparison of Kaposi Sarcoma Risk in HIV-Positive Adults Across 5 Continents: A Multiregional Multicohort Study

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Background. We compared Kaposi sarcoma (KS) risk in adults who started antiretroviral therapy (ART) across the Asia-Pacific, South Africa, Europe, Latin, and North America.
Methods. We included cohort data of human immunodeficiency virus (HIV)–positive adults who started ART after 1995 within the framework of 2 large collaborations of observational HIV cohorts. We present incidence rates and adjusted hazard ratios (aHRs).
Results. We included 208 140 patients from 57 countries. Over a period of 1 066 572 person-years, 2046 KS cases were diagnosed. KS incidence rates per 100 000 person-years were 52 in the Asia-Pacific and ranged between 180 and 280 in the other regions. KS risk was 5 times higher in South African women (aHR, 4.56; 95% confidence intervals [CI], 2.73–7.62) than in their European counterparts, and 2 times higher in South African men (2.21; 1.34–3.63). In Europe, Latin, and North America KS risk was 6 times higher in men who have sex with men (aHR, 5.95; 95% CI, 5.09–6.96) than in women. Comparing patients with current CD4 cell counts ≥700 cells/μL with those whose counts were <50 cells/μL, the KS risk was halved in South Africa (aHR, 0.53; 95% CI,.17–1.63) but reduced by ≥95% in other regions.
Conclusions. Despite important ART-related declines in KS incidence, men and women in South Africa and men who have sex with men remain at increased KS risk, likely due to high human herpesvirus 8 coinfection rates. Early ART initiation and maintenance of high CD4 cell counts are essential to further reducing KS incidence worldwide, but additional measures might be needed, especially in Southern Africa.