Supplemental File 1: Additional Information on Methods

Study population

The questionnaire contained information on sociodemographic and behavioral characteristics, medications (both HAART and non-HAART), medical history and HIV-related symptoms (Kaslow et al, 1987, Lazo et al, 2007). HIV seropositivity was tested using ELISA and confirmed by Western blot (Desquilbet et al, 2011). The quantification of T-cell subsets was performed using standardized flow cytometry (Lazo et al, 2007, Schenker et al, 1993) in laboratories participating in the National Institutes of Health/National Institute of Allergy and Infectious Diseases AIDS Program (NIH/NIAID) Flow Cytometry Quality Assessment Program (Calvelli et al, 1993, Giorgi et al, 1990). The RT-PCR technique (Roche Molecular System) was used to measure HIV viral load and was performed at the laboratories participating in the NIH/NIAID Virology Quality Assurance Proficiency Testing Program (Lazo et al, 2007).

Kaposi’s sarcoma ascertainment and classification

Cases of cancer among cohort members were identified using different methods such as interview, medical record abstraction, and vital status review, which included data from the National Death Index. Before 2005, the International Classification of Disease for Oncology, first edition (ICD-O-1), was used to document cancer cases in MACS. After 2005, the International Classification of Disease for Oncology, 3rd edition (ICD-O-3) was used for this purpose. Also, a standardized algorithm was used to convert cancer sites and histology from ICD-O-1 to ICD-O-3 (Seaberg et al, 2010, Ferlay et al, 2005 ).

Definition of HAART in MACS study

A person was defined on HAART if he received three or more antiretroviral drugs consisting one or more Protease inhibitors (PIs) or one non-nucleoside reverse transcriptase inhibitors (NNRTIs) or nucleoside reverse transcriptase inhibitors (NRTIs) – Abacavir or Tenofovir, or an integrase or an entry inhibitor. Specific combinations subject to the following restriction criteria included (a) two or more NRTIs with one NNRTI or with one or more PIs (87%); (b) one NNRTI co-administered with one ritonavir (RTV) boosted PI with or without NRTI (7%); (c) an abacavir or tenofovir containing regimen of three or more NRTIs in the absence of both PIs and NNRTIs (4%); (d) two or more RTV boosted PIs with or without other ARTs (1%); and (e) an integrase or entry inhibitor with a combination of two other antiretroviral drugs (1%) except for two unboosted PIs. Regimens containing the following combinations were not considered HAART: two or more NNRTIs, an NNRTI without a (RTV) boosted PI, unboosted atazanavir with TDF, boosted nelfinavir (NFV), and two NRTI combinations - zidovudine (AZT) + stavudine (d4T) or emtricitabine (FTC) + lamivudine (3TC). Enfuvirtide (T-20) or Maraviroc (Selzentry) or Ralegravir (Isenress) with two or more antiretroviral drugs except for all exclusions listed above were considered HAART. All other ART regimens were classified as combination therapy that did not meet the HAART definition (DHHS/Henry J Kaiser Family Foundation Panel on Clinical Practices for the Treatment of HIV Infection, 2008).