Distinct risks, clinical characteristics and outcomes by age at time of HIV diagnosis

New HIV diagnoses in persons aged > 50 years (hereafter 'older persons') are becoming more common; the clinical features and outcomes of these older individuals are poorly described.

We conducted a retrospective cohort study of all new adult HIV diagnoses between October 1989 and December 2019 in southern Alberta, Canada. Differences in risk for HIV acquisition and screening, sociodemographic/clinical characteristics, and causes of death were compared between individuals younger and older than 50 years at the time of diagnosis.

New HIV diagnoses in persons > 50 years old increased from 7% in 1990 to 18% in 2019. Risk for HIV acquisition and screening reasons differed by age. Heterosexual sex (29%) was the greatest risk factor among older persons, contrasting with male same sex activity in younger persons (51%) (P < 0.001). Illness was the most common indication for testing in older persons (47%), whereas younger persons were more likely to have requested testing (34%) (P < 0.001). Relationship status differed, with 33% of older persons being married to an opposite sex partner versus 12% in younger persons (P < 0.001). Although older persons had a lower mean nadir CD4 count (132 cells/µL) than younger persons (181 cells/µL) (P < 0.001), 80% of deaths between 2010 and 2019 in the older group were attributable to non-AIDS-related causes versus 47% in younger patients. Since 2000, AIDS-related deaths and potential years of life lost have declined for both age groups.

The increase in new HIV diagnoses in persons aged > 50 years in southern Alberta suggests that older individuals require customized approaches for optimizing HIV diagnosis and treatment.