AIDS in the era of antiretroviral therapy: Changes in incidence rates and predictors of AIDS among people living with HIV under clinical care in Germany, a cohort study 1999–2018

Abstract

Objectives: This study examined the incidence rates and predictive utility of established prognostic factors for the progression to AIDS among people living with HIV under clinical care. Methods:We used data from two observational cohorts of people living with HIV in Germany between 1999 and 2018. The outcome measure was the first AIDS-defining event that occurred during follow-up. Incidence rates (IRs) per 1000 person-years (PY) were calculated by years of follow-up and calendar periods. We used Cox models in our prediction analyses, including CD4 count, viral load, and age at baseline to estimate the predictive performance. Additionally, we included transmission mode to examine its predictive utility.Results: A total of 23 299 people living with HIV were included in the analyses. Of these, 1832 developed a first AIDS event during follow-up, constituting an overall rate of 14.6/1000 PY (95% confidence interval [CI] 13.9-15.2).IRs were highest in the first year of follow-up (45.6/1000 PY, 95% CI 42.6-48.8) and then declined continuously. IRs were highest among people living with HIV who enrolled between 1999 and 2003 (36.1/1000 PY, 95% CI 32.6-40.0). A low CD4 count, high viral load, and older age at baseline increased the likelihood of progressing to AIDS. Adding transmission mode to the models did not improve the predictive performance. Conclusions:The rates of a first AIDS event among people living with HIV have continuously declined in Germany. Health outcomes depend on a person's CD4 count, viral load, and age but not on transmission mode. To further