Long-term impact of highly active antiretroviral therapy on HIV-related health care costs

CONTEXT: Highly active antiretroviral therapy (HAART) is associated with decreased opportunistic infections, hospitalization, and HIV-related health care costs over relatively short periods of time. We have previously demonstrated that decreases in total HIV cost are proportional to penetration of protease inhibitor therapy in our clinic. OBJECTIVE: To determine the effects of HAART on HIV health care use and costs over 44 months. SETTING: A comprehensive HIV service within a Veterans Affairs Medical Center. DESIGN: A cost-effectiveness analysis of HAART. MAIN OUTCOME MEASUREMENTS: The mean monthly number of hospital days, infectious diseases clinic visits, emergency room visits, non-HIV-related outpatient visits, inpatient costs, and antiretroviral treatment costs per patient were determined by dividing these during the period from January 1995 through June 1998 into four intervals. Viral load tests were available from October 1996. Cost-effectiveness of HAART was evaluated by determining the costs of achieving an undetectable viral load over time. RESULTS: Mean monthly hospitalization and associated inpatient costs decreased and remained low 2 years after the introduction of protease inhibitors (37 hospital days per 100 patients). Total cost decreased from $1905 per patient per month during the first quarter to $1090 per patient per month in the third quarter but increased to $1391 per patient per month in the fourth quarter. Antiretroviral treatment costs increased throughout the entire observation period from $79 per patient per month to $518 per patient per month. Hospitalization costs decreased from $1275 per patient per month in the first quarter to less than $500 per patient per month in each of the third and fourth quarters. The percentage of patients with a viral load <500 copies/mL increased from 21% in October 1996 to 47% in June of 1997 (p =.014). The cost of achieving an undetectable viral load decreased from $4438 per patient per month to $2669 per patient per month, but this trend did not reach statistical significance (p =.18). CONCLUSIONS: After an initial decrease, there was an increase in the total monthly cost of caring for HIV patients. Cost increases were primarily due to antiretroviral treatment costs, but these costs were offset by a marked decrease in inpatient-related costs. Increases in costs were not related to antiretroviral treatment failures as measured by the proportion of patients with low or undetectable viral loads. The cost of achieving an undetectable viral load remained stable despite increases in the cost of procuring antiretroviral agents.