Bipolar disorder in people with HIV

To assess whether bipolar disorders are associated with the risk of HIV infection and whether the risk of bipolar disorders is increased among people with HIV (PWH) and their siblings.

Nationwide, population-based, combined matched nested case-control and cohort study of PWH of Danish origin (1995-2021), a comparison cohort from the background population, matched on date of birth and sex, and sibling cohorts.

Conditional logistic regression and Cox regression was used to calculate adjusted odds ratios (aORs) for HIV infection and hazard ratios among PWH for bipolar disorder and receipt of lithium.

We included 5322 PWH and 53 220 comparison cohort members. In the case-control study, bipolar disorder was associated with an increased risk of HIV infection [aOR: 1.9, 95% confidence interval (CI): 1.2-3.0], especially when injection drug use was the route of infection (aOR: 7.6, 95% CI: 2.0-28.9). In the cohort study, we observed an increased risk of bipolar disorders among PWH, especially in the first 2 years of observation (hazard ratio: 4.2, 95% CI: 2.4-7.4), whereas the risk of receipt of lithium was lower and the CI crossed 1. The 20-year risk of bipolar disorders for PWH was approximately 1%. Siblings of PWH also had an increased risk of bipolar disorder but not to the same degree as PWH and not of receipt of lithium.

Bipolar disorders are associated with the risk of HIV infection, and PWH have increased risk of bipolar disorder and receipt of lithium beyond what familial factors could explain.