Effect of once-daily FDC treatment era on initiation of cART

Objectives: Combination antiretroviral therapy (cART) is associated with increased survival among HIV-infected persons. Yet, no research to date has examined whether introduction of once-daily fixed-dosed combinations (FDC) affects the likelihood of cART initiation. We aimed to determine whether implementation of once-daily FDC regimens was associated with changes to cART initiation. We also identified clinical, treatment regimen, and provider characteristics possibly associated with cART initiation.

Study design: Retrospective observational analysis.

Methods: We queried electronic medical records between July 1999-June 2006 to identify incident cases of detectable HIV infection in antiretroviral-naïve adults. Cox regression with time-dependent covariates was used to examine the effects of once-daily FDC era, clinical, provider, and treatment regimen characteristics on cART initiation.

Results: Once-daily FDC availability did not change the likelihood of cART initiation, but other characteristics were associated with an increased likelihood: AIDS diagnosis, above-median daily pill consumption, and 16+ yrs of physician HIV experience. Decreased likelihood of cART initiation was associated with CD4 201-350 cells/μL, HIV RNA < 100,000 copies/mL, and with CD4 > 350 cells/μL (any HIV RNA level), compared to CD4 ≤ 200 cells/μL.

Conclusion: Availability of once-daily FDC-based regimens did not affect likelihood of cART initiation. Patient clinical characteristics appear to be more important predictors of cART initiation.