Longitudinal trends in causes of death among adults with HIV on antiretroviral therapy in Europe and North America from 1996 to 2020: a collaboration of cohort studies

Background Mortality rates among people with HIV have fallen since 1996 following the widespread availability of effective antiretroviral therapy (ART). Patterns of cause-specific mortality are evolving as the population with HIV ages. We aimed to investigate longitudinal trends in cause-specific mortality among people with HIV starting ART in Europe and North America. Methods In this collaborative observational cohort study, we used data from 17 European and North American HIV cohorts contributing data to the Antiretroviral Therapy Cohort Collaboration. We included data for people with HIV who started ART between 1996 and 2020 at the age of 16 years or older. Causes of death were classified into a single cause by both a clinician and an algorithm if International Classification of Diseases, Ninth Revision or Tenth Revision data were available, or independently by two clinicians. Disagreements were resolved through panel discussion. We used Poisson models to compare cause-specific mortality rates during the calendar periods 1996-99, 2000-03, 2004-07, 2008-11, 2012-15, and 2016-20, adjusted for time-updated age, CD4 count, and whether the individual was ART -naive at the start of each period. Findings Among 189 301 people with HIV included in this study, 16 832 (8 center dot 9%) deaths were recorded during 1 519 200 person-years of follow-up. 13 180 (78 center dot 3%) deaths were classified by cause: the most common causes were AIDS (4203 deaths; 25 center dot 0%), non-AIDS non -hepatitis malignancy (2311; 13 center dot 7%), and cardiovascular or heart-related (1403; 8 center dot 3%) mortality. The proportion of deaths due to AIDS declined from 49% during 1996-99 to 16% during 2016-20. Rates of all-cause mortality per 1000 person-years decreased from 16 center dot 8 deaths (95% CI 15 center dot 4-18 center dot 4) during 1996-99 to 7 center dot 9 deaths (7 center dot 6-8 center dot 2) during 2016-20. Rates of all-cause mortality declined with time: the average adjusted mortality rate ratio per calendar period was 0 center dot 85 (95% CI 0 center dot 84-0 center dot 86). Rates of cause-specific mortality also declined: the most pronounced reduction was for AIDS-related mortality (0 center dot 81; 0 center dot 79-0 center dot 83). There were also reductions in rates of cardiovascular-related (0 center dot 83, 0 center dot 79-0 center dot 87), liver-related (0 center dot 88, 0 center dot 84-0 center dot 93), non-AIDS infectionrelated (0 center dot 91, 0 center