The following is a summary of “A Growing Number of Men Who Have Sex With Men Aging With HIV (2021–2031): A Comparison of Two Microsimulation Models,” published in the February 2023 issue of Infectious Diseases by Hyle, et al.

Antiretroviral therapy (ART)-using men who have sex with other men (MSM) are at risk for multimorbidity as life expectancy rises. For a study, researchers sought to aid in developing health policy, simulation models can estimate population sizes and age distributions.

To estimate the HIV epidemic among MSM in the US, they loaded the CEPAC-US model with CDC data. NA-ACCORD data served as the primary input source for the PEARL model (2009–2017). They evaluated the anticipated population numbers and age distributions of MSM receiving ART (2021–2031) and looked into how assumptions and factors impacted the findings.

A growing and older MSM population were predicted to be on ART: CEPAC-US, mean age 48.6 (SD 13.7) years in 2021 compared to 53.9 (SD 15.0) years in 2031; PEARL, 46.7 (SD 13.2) years compared to 49.2 (SD 14.6) years. They predicted that 548,800 MSM on ART  (147,020 ≥ 65 years)  and 599,410 (113,400 ≥ 65 years) would be available in 2031 (CEPAC-US) (PEARL). By 2031, CEPAC-US predicted fewer MSM would be on ART than PEARL predicted, and the population would grow more slowly. This was due to greater projections of mortality and care-related disengagement.

According to results from two fundamentally different microsimulation models, the MSM population getting ART in the US was predicted to grow and age during the following ten years. Projections can be improved, and subgroup-specific data can inform healthcare policy planning on mortality and engagement in care.