Does combining antiretroviral agents in a single dosage form enhance quality of life of HIV/AIDS patients?
Combining various antiretroviral agents into one single dosage form has been a strategy to reduce pill burden and enhance medication adherence among human immunodeficiency virus /AIDS (HIV/AIDS) patients. This is a cost-utility study from a health care system's perspective comparing coformulated fixed dose (FXD) strategy versus multiple free dose combination (FRC) in antiretroviral therapy. The Medical Expenditure Panel Survey (MEPS) was used to identify HIV/AIDS patients with ≥2 active antiretroviral medications. Patients on FXD were matched in 1:1 ratio with the FRC group using propensity scores. All medical costs excluding those paid by patients and families were included. Utility was measured using SF-6D scores from the SF-12 questionnaire. Incremental cost-utility ratios (ICURs) were calculated using the mean annual estimates. A cost-effectiveness acceptability curve was determined using a Monte Carlo probabilistic simulation technique. Nine FXD antiretroviral formulations approved by the U.S. Food and Drug Administration by 2005 was included in this study. One hundred seventy HIV/AIDS patients with ≥2 antiretroviral agents were identified from the MEPS database, of which 53% (n=92) were on FXD formulation. On matching, 70 patients from FXD had a match from the FRC group. No differences in sociodemographic and health status variables were observed between the matched groups. The mean annual cost was $15,766.15 for FXD patients and $11,875.21 for FRC patients. The mean utility gained by using FXD over FRC was 0.085; however, this difference was not statistically significant. The ICUR for the FXD treatment over FRC treatment was $45,540.49/quality-adjusted life years (QALYs). Probabilistic sensitivity analysis showed FXD to dominate FRC (>50% probability of being cost-effective) above the $40,000 threshold.
Although the cost-effectiveness of a single-pill strategy was within the acceptable willingness-to-pay threshold, the QALY difference were minimal. Further research is recommended to explore the long-term impact of the strategy.