Objectives: In the USA, Medicaid is the principal payer of the health care costs of patients with HIV infection. We wished to determine how the costs to Medicaid of patients in Maryland infected with HIV have changed in the setting of highly active antiretroviral treatment.
Design: Observational cohort study.
Methods: Analysis of combined economic and clinical data of patients from the Johns Hopkins HIV Service, the provider of primary and sub-specialty care for a majority of HIV-infected patients in the Baltimore metropolitan region. All patients were enrolled in Medicaid and received care longitudinally in Maryland from 1 January 1995 through 31 December 1997. Monthly Medicaid payments were calculated for all inpatient and outpatient services by fiscal year, CD4 cell count, and use of protease inhibitors.
Results: For inpatients with a CD4 cell count < or = 50 x 10(6) cells/l, the total health care average monthly payments remained unchanged ($2629 in 1995, $2585 in 1997). Total mean monthly payments increased for those with a CD4 cell count > 50 x 10(6) cells/l (CD4 cell count 50-200 x 10(6) cells/l, $1172 in 1995 and $1615 in 1997, P < 0.05; CD4 cell count 201-500 x 10(6) cells/l, $1078 in 1995 and $1305 in 1997, P < 0.05). However, when data were stratified according to use of a protease inhibitor-containing regimen (used during approximately 50% of follow-up time in 1996-1997) it was found that hospital inpatient payments decreased significantly in all CD4 strata for patients on a protease inhibitor-containing regimen whereas pharmacy payments increased significantly. Inpatient payments associated with treating opportunistic illness were lower in 1996-1997 for patients receiving protease inhibitor therapy compared with those not receiving protease inhibitors. On balance, total health care payments tended to be slightly lower for patients receiving a protease inhibitor regimen.
Conclusion: Although protease inhibitor-containing antiretroviral regimens are being used by only about half of our Medicaid-insured patients, when they are used, there are significantly lower hospital inpatient and community care costs, as well as lower costs associated with the treatment of opportunistic illness. Even with the concurrent increase in their pharmacy costs, total health care costs were stable or slightly lower for these patients. We believe this is a favorable result suggesting a good clinical value being achieved without an increase in costs.