Pneumonia and influenza hospitalizations in American seniors: The impact of HIV

Background: With the introduction of anti-retroviral therapy, HIV-positive persons are surviving to an older age in the US. Persons aged ≥65 are a high risk group for influenza-related complications, because of age- associated immune dysfunction. HIV infection in the elderly may have a synergistic effect with aging, and increase the severity of influenza-related complications in such persons. Design: Using hospitalization claims data maintained by the Center for Medicare and Medicaid Services (CMS) over a 14-year period, we described the demographic and temporal patterns of Pneumonia and Influenza (P&I) hospitalizations in HIV-positive and -negative seniors, and compared outcome of P&I hospitalization with respect to HIV status. Results: The proportion of seniors hospitalized for P&I with concurrent HIV more than doubled between 1991 and 2004, from 27 to 56 per 100,000 P&I hospitalizations respectively. HIV-positive seniors were younger on average than HIV-negative seniors (70 years vs. 80 years, P<0.001). In-hospital death was more frequent among HIV-positive records (18% vs. 13% for HIV-negative persons, P<0.001). The proportion of HIV-positive persons who died in hospital declined over the 14-year period (from 30% in 1991 to 15% in 2004). A gap in in-hospital mortality nevertheless persisted in 2004, with HIV-positive persons being 50% more likely to die during the course of P&I hospitalization compared to HIV-negative persons (P<0.001). Conclusion: HIV-infected persons represent an expanding fraction of the elderly population that is hospitalized with P&I. Efforts to improve outcomes of P&I in seniors should include not only immunization of HIV-positive persons but also increased HIV screening.