Determinants of the cost of health services used by veterans with HIV.

Background: The effect of adherence, treatment failure, and comorbidities on the cost of HIV care is not well understood.

Objective: To characterize the cost of HIV care including combination antiretroviral treatment (ART).

Research Design: Observational study of administrative data.

Subjects: Total 1896 randomly selected HIV-infected patients and 288 trial participants with multidrug-resistant HIV seen at the US Veterans Health Administration (VHA).

Measures: Comorbidities, cost, pharmacy, and laboratory data.

Results: Many HIV-infected patients (24.5%) of the random sample did not receive ART. Outpatient pharmacy accounted for 62.8% of the costs of patients highly adherent with ART, 32.2% of the cost of those with lower adherence, and 6.2% of the cost of those not receiving ART. Compared with patients not receiving ART, high adherence was associated with lower hospital cost, but no greater total cost. Individuals with a low CD4 count (<50 cells/mm) incurred 1.9 times the cost of patients with counts >500. Most patients had medical, psychiatric, or substance abuse comorbidities. These conditions were associated with greater cost. Trial participants were less likely to have psychiatric and substance abuse comorbidities than the random sample of VHA patients with HIV.

Conclusions: Patients receiving combination ART had higher medication costs but lower acute hospital cost. Poor control of HIV was associated with higher cost. The cost of psychiatric, substance abuse, rehabilitation, and long-term care and medications other than ART, often overlooked in HIV studies, was substantial.