Background:  For some patients, combination antiretroviral therapy (cART) has simplified to one pill, once daily. We compared adherence to a FDC of EFV/FTC/TDF to non-one-pill, once daily regimens in a cohort of homeless and marginally housed individuals. Adherence was measured using unannounced pill counts.

Methods:  Individuals on either EFV/FTC/TDF FDC, or cART with a ritonavir-boosted (PI/r), unboosted protease inhibitor (PI), or non-nucleoside reverse transcriptase inhibitors (NNRTI) were recruited from single room occupancy hotels, free meal food programs and homeless shelters in the REACH Cohort. The sample was oversampled for individuals on EFV/FTC/TDF FDC. Individuals were recruited within 6 months of treatment initiation. Adherence was followed for 6 months using unannounced pill counts at the usual place of residence. We compared >90% monthly unannounced pill count adherence using generalized estimating equations (GEE) for EFV/FTC/TDF FDC vs all other daily regimens controlling for age, gender, homelessness, injection drug use status, CD4 nadir, time on regimen, and Beck Depression Inventory. In sub-analyses, we compared adherence to EFV/FTC/TDF FDC vs PI/r-based cART; and EFV/TDF/FTC FDC vs. other NNRTI-based cART regimens.

Results:  In this study, 129 individuals were recruited, including 47 EFV/TDF/FTC FDC, 14 NNRTI, 57 PI/r and 11 PI-treated individuals. Participant characteristics included: age 45 yr (mean), 73% male, 41% nonwhite, 76% homeless (ever), 67% high school educated. Mean adherence to: EFV/TDF/FTC FDC was 0.86 ± 0.18; all non-one-pill daily regimens 0.73 ± 0.22; PI/r 0.75 ± 0.21, NNRTI 0.68 ± 0.26, and PI 0.73 ± 0.27 In GEE analysis, adherence was higher in EFV/TDF/FTC FDC regimen compared to non-one-pill once daily therapy (P =0.0014). Other predictors of higher adherence included higher income (P =0.01), and lower CD4 nadir (P =0.004). Sub analyses indicated higher adherence in EFV/TDF/FTC FDC compared to either PI/r (P =0.006) and NNRTI regimens (P =0.03). There was no difference in HIV RNA <50 copies/mL suppression between groups.

Conclusions:  One-pill-daily EFV/TDF/FTC FDC use is associated with higher adherence than other non-one-pill-daily regimens in an urban poor population.