Healthcare costs associated with antiretroviral adherence among medicaid patients.

BACKGROUND: The relationship of antiretroviral therapy (ART) adherence to total healthcare expenditures for Medicaid-insured people living with HIV or AIDS (PLWHA) is not well understood, especially among asymptomatic HIV-positive patients.

OBJECTIVE: This study examined Medicaid-insured HIV-positive and AIDS-diagnosed patient groups to determine the association of ART adherence to mean monthly total healthcare expenditures in the 24-month measurement period, controlling for demographic, geographic, insurance, and clinical factors. The present study extends the existing literature by analyzing the relationship of ART adherence to total healthcare costs for asymptomatic HIV-positive patients separately from those patients with AIDS-defining conditions.

METHODS: This retrospective study utilized claims data from Florida Medicaid claims from July 2006 through June 2011. All patients (n = 502) were HIV-positive, aged 18-64 years, non-pregnant, and ART naïve for at least 12 months prior to the measurement period. Each patient was categorized, based on medication possession ratios, as adherent (≥90 %) or non-adherent (<90 %), and were divided into two groups: HIV positive (n = 232) and AIDS diagnosed (n = 270). Generalized linear models predicted the mean monthly total expenditures for the non-adherence group versus the adherence group.

RESULTS: For the HIV-positive group, the adjusted mean monthly expenditures for the non-adherent group were US$1,291; the adherent group adjusted mean monthly expenditures were US$1,926. The HIV-positive non-adherent group adjusted mean monthly expenditures were significantly less than the adherent group (-40 %, p < 0.001). However, for the AIDS-diagnosed group, there was not a statistically significant association of ART adherence to total healthcare expenditures (p = 0.29).

CONCLUSION: The results show that the relationship of ART adherence to healthcare costs is more complex than previously reported.