Marian E. Betz, MD, MPH, Kelly A. Gebo, MD, MPH, Ed Barber, MPH, Peter Sklar, MD, MPH, John A. Fleishman, PhD, Erin D. Reilly, MPH, and W. Christopher Mathews, MD, MSPH, for the HIV Research Network

Med Care 2005;43: III-3–III-14

Background
Admissions for AIDS-related illnesses decreased soon after the introduction of highly active antiretroviral therapy (HAART), but it is unclear if the trends have continued in the current HAART era. An understanding of healthcare utilization patterns is important for optimization of care and resource allocation. We examined the diagnoses for hospitalizations of patients with HIV in 2001.

Methods
Demographic and healthcare data were collected for 8376 patients from 6 U.S. HIV care sites in 2001. We categorized diagnoses into 18 disease groups and used Poisson regression to analyze the number of admissions for each of the 4 most common groups. We also compared patients with admissions for AIDSdefining illnesses (ADI) with patients admitted for other diagnoses.

Results
Twenty-one percent of patients had at least 1 hospitalization. Among patients hospitalized at least once, 28% were hospitalized for an ADI. Comparing diagnosis categories, the most common hospitalizations were AIDS-defining illnesses (21.6%), gastrointestinal (GI) diseases (9.5%), mental illnesses (9.0%), and circulatory diseases (7.4%). In multivariate analysis, women had higher hospitalization rates than men for ADI (incidence rate ratio _IRR_, 1.50; 95% confidence interval _CI_, 1.25–1.79) and GI diseases (IRR, 1.52; 95% CI, 1.15–2.00). Compared with whites, blacks had higher admission rates for mental illnesses (IRR, 1.70; 95% CI, 1.22–2.36), but not for ADI. As expected, CD4 count and viral load were associated with ADI admission rates; CD4 counts were also related to hospitalizations for GI and circulatory conditions.

Conclusion
Five years after the introduction of HAART, AIDSdefining illnesses continue to have the highest hospitalization rate among the diagnosis categories examined. This result emphasizes the importance of vaccination for pneumonia and influenza, as well as prophylaxis for Pneumocystis jiroveci pneumonia. The relatively large number of mental illness admissions highlights the need for comanagement of psychiatric disease, substance abuse, and HIV. Overall, the majority of patients were hospitalized for reasons other than ADI, illustrating the importance of managing comorbid conditions in this population. Data from this cohort of patients with HIV may help guide the allocation of healthcare resources by enhancing our understanding of factors associated with variation in inpatient utilization rates.

[download article]