Rates of hospitalizations and associated diagnoses in a large multisite cohort of HIV patients in the United States, 1994–2005

Abstract

To assess temporal trends in the rates of hospitalizations and associated diagnoses among HIV-infected patients before and during the era of highly active antiretroviral therapy. A prospective cohort study of 7155 patients enrolled in the HIV Outpatient Study at 10 US HIV clinics. We evaluated rates of hospitalizations for major categories of medical conditions during 1994-2005 and modeled trends in these rates using multivariable Poisson regression models for repeated observations. We assessed patient characteristics associated with hospitalization using multiple logistic regression. The rates of hospitalizations (per 100 person-years) fell from 24.6 in 1994 to 11.8 in 2005 (P < 0.0001). The rates of hospitalizations for AIDS opportunistic infections decreased from 7.6 in 1994-1996 to 1.0 in 2003-2005 (P < 0.0001). AIDS opportunistic infections were present at 31% of hospitalizations in 1994-1996 versus 9.5% in 2003-2005, and chronic end-organ disease conditions were present at 7.2% of such hospitalizations in 1994-1996 versus 14.3% in 2003-2005. Mean CD4+ cell count at hospitalization increased from 115 cells/mul in 1994 to 310 cells/mul in 2005. Factors independently associated with hospitalization in the highly active antiretroviral therapy era (1997-2005) included older age, history of substance abuse, lower CD4+ cell count, history of AIDS, and public health insurance. The rates of hospitalizations for HIV-infected patients declined substantially during 1994-2005, due mainly to reductions in the AIDS opportunistic infections. Compared with the period 1994-1997, patients in the highly active antiretroviral therapy era were hospitalized with higher CD4+ cell counts and more frequently for chronic end-organ conditions.