Objective: The objective of this study was to examine adherence and persistency in HIV patients initiating first-line combination antiretroviral therapy (cART) with a non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimen.
Methods: Using US health insurance records, the authors identified all persons aged ≥ 18 years with HIV, who began NNRTI-based cART between 1 January 2003 and 30 September 2009. They examined adherence using proportion of days covered (PDC), and non-persistency based on evidence of discontinuation, switching or augmentation. Differences in non-adherence (1 - PC) and non-persistency were compared over 12 months, between three treatment groups: i) efavirenz, emtricitabine and tenofovir as a fixed-dose combination ('EFV/FTC/TDF'); ii) EFV-based regimens other than EFV/TDF/FTC, with ≥ 2 NRTIs ('EFV + ≥ 2 NRTIs'); and iii) nevirapine-based regimens with ≥ 2 NRTIs (NVP + ≥ 2 NRTIs).
Results: There were 1874 patients receiving EFV/FTC/TDF, 893 receiving EFV + ≥ 2 NRTIs and 207 receiving NVP + ≥ 2 NRTIs. Adherence was lower for both EFV + ≥ 2 NRTIs and NVP + ≥ 2 NRTIs than for EFV/FTC/TDF (rate ratio (RR) = 1.57 and 2.01, respectively; both p < 0.01), while non-persistency was higher (hazard ratio (HR) = 1.56, p < 0.01 and 1.70, p < 0.01, respectively).
Conclusion: Adherence and persistency may differ between NNRTI-based regimens; additional analyses are needed to understand the reasons for these differences.