Background: Mortality among people with human immunodeficiency virus (HIV) declined with the introduction of combination antiretroviral therapy. We investigated trends in mortality in people with HIV from 1999 through 2020.

Methods: Data were collected from the Data Collection on Adverse events of Anti-HIV Drugs (D:A:D) cohort between January 1999 through January 2015 and the International Cohort Consortium of Infectious Disease (RESPOND) from October 2017 through December 2020. Age-standardized all-cause and cause-specific mortality rates, classified using Coding Causes of Death in HIV, were calculated. Poisson models were used to assess mortality over time.

Results: Among 55 716 participants followed for median 6 years (interquartile range, 3-11), 5263 died (mortality rate [MR], 13.7/1000 person-years of follow-up [PYFU]; 95% confidence interval [CI], 13.4-14.1). Changing mortality was observed: AIDS mortality was most common between 1999-2009 (n = 952; MR, 4.2/1000 PYFU; 95% CI, 4.0-4.5) and non-AIDS-defining malignancy (NADM) between 2010-2020 (n = 444; MR, 2.8/1000 PYFU; 95% CI, 2.5-3.1). In multivariable analysis, all-cause mortality declined (adjusted mortality rate ratio [aMRR], 0.97 per year; 95% CI, .96-.98), mostly 1999-2010 (aMRR, 0.96 per year; 95% CI, .95-.97) but was stable 2011-2020 (aMRR, 1.00 per year; 95% CI, .96-1.05). Mortality due to all known causes except NADM also declined.

Conclusions: Mortality among people with HIV in the D:A:D and/or RESPOND cohorts declined between 1999-2009 and was stable over the period 2010-2020. This decline in mortality was not fully explained by improvements in immunologic-virologic status or other risk factors.