Incidence and Impact on Mortality of Severe Neurocognitive Disorders in Persons With and Without HIV Infection: A Danish Nationwide Cohort Study

Objective. The risk of neurocognitive disorders in human immunodefiency virus (HIV)–infected patients in the era of highly active antiretroviral therapy (HAART) is controversial. We aimed to compare the incidence and impact on mortality of severe neurocognitive disorders (SNCDs) in HIV-infected patients with that of the background population. Methods. The method used was a nationwide, population-based cohort study using Danish registries. We calculated incidence rates, incidence rate ratios, mortality rate ratios, and Kaplan–Meier tables to estimate the incidence of and survival after SNCD in HIV-infected patients, compared with a general population control cohort matched by age and sex. Results. We observed 32 cases of SNCDs among 4452 HIV-infected patients and 120 cases of SNCDs among 62 328 population control subjects. The overall risk of SNCD among HIV-infected patients was 1.0 case per 1000 person-years (PYR), compared with 0.23 cases per 1000 PYR for population control subjects but became 0.35 cases/1000 PYR after 2004, compared with 0.27 cases/1000 PYR in population control subjects. The absence of HAART and a low CD4 lymphocyte count increased the risk of SNCD. The mortality among HIV-infected patients with SNCD was higher than that among population controls with SNCD (median survival, 4.3 years vs 9.7 years [P = .02]). Conclusion. HIV-infected patients have an increased risk of SNCD, but the risk is low and has, in recent years, become comparable to that seen in the background population. In contrast, the mortality remains high among HIV-infected patients diagnosed with SNCD.