Association between pharmacy medication refill-based adherence rates and cd4 count and viral-load responses: A retrospective analysis in treatment-experienced adults with HIV

Background:Current guidelines and most contemporary statements in the literature indicate that, like other medical conditions, HIV infection requires exceptionally high adherence to highly active antiretroviral therapy (HAART) for successful treatment.Objective:This study was conducted to determine the association between pharmacy medication refill rates—a surrogate marker for adherence to HAART— and CD4-count/viral-load responses in patients with HIVMethods:This retrospective study was conducted at the HIV Clinic, Veterans Affairs Medical Center, Durham, North Carolina. Male and female patients aged ≥18 years with a history of HIV who attended clinic appointments on 3 consecutive clinic days were enrolled. Pharmacy medication refill-based adherence rates over the 6 months before the study were determined by examining electronic pharmacy records. The most recent viral load and the change (Δ) in CD4 count over the past year-surrogate measures of outcome—were also collected from each patient's electronic medical record and compared with refill adherence rates. The incidence of AIDS-related events and past antiretroviral experience were also compared with the ΔCD4 count and adherence rates.Results:Data from 58 patients were included in the study. Thirty-nine patients were black men; the mean age was 51.5 years. There was a nonsignificant correlation between 6-month pharmacy medication refillbased adherence rates and viral loads (r = 0.10). The relationship between ΔCD4 count and adherence was complex. With adherence rates >70%, the ΔCD4 count ranged from +414 to -238, with no indication that increasing adherence led to a greater CD4 count increase. The ΔCD4 count progressively declined with adherence rates ≤70%. Patients' past antiretroviral experience or incidence of AIDS-related events did not significantly affect the distribution of ΔCD4 counts or adherence rates.Conclusion:Based on our results, in patients with pharmacy medication refill-based adherence rates >70%, there was no significant correlation between adherence rates and ΔCD4 counts or viral-load responses.