Highly Active Antiretroviral Therapy: Physician Experience and Enhanced Adherence to Prescription Refill

Abstract

Objective

To identify patient and physician characteristics that may act as determinants of adherence to prescription refill of triple combination antiretroviral therapy.

Methods

A population-based analysis of antiretroviral therapy-naive HIV-positive men and women in British Columbia, Canada, who initiated triple combination therapy between August 1 1996 and October 31 1998. Study participants were considered adherent if they were actually dispensed antiretrovirals ≥95% over the first year of therapy. Log-binomial regression was used to identify patient and physician characteristics associated with adherence to prescription refill.

Results

Of the 886 individuals eligible for analysis, 495 (56%) were ≥95% adherent to prescription refill. In multivariate analysis, adherence was positively associated with increased age [adjusted relative rate (ARR) 1.19; 95% CI: 1.07–1.32], having a diagnosis of AIDS (ARR 1.66; 95% CI: 1.29–2.15), being male (ARR 1.79; 95% CI: 1.27–2.53), and with greater experience of the treating physician (ARR 1.27; 95% CI: 1.13–1.42). History of injection drug use was negatively associated with adherence to prescription refill (ARR 0.65; 95% CI: 0.51–0.83), as was increased pill burden (per pill daily) (ARR 0.95; 95% CI: 0.92–0.99). A sub-analysis of 316 patients who provided additional data regarding psychosocial characteristics indicated that adherence was positively associated with physician experience (ARR: 1.28; 95% CI: 1.09–1.51) and being employed (ARR: 1.55; 95% CI: 1.14–2.21), and negatively associated with a history of injection drug use (ARR: 0.61; 95% CI: 0.43–0.85).

Conclusion

While patient disease stage and personal characteristics may play an important role in patient adherence to prescription refill of complex therapeutic regimens, our findings indicate that HIV-experienced physicians may have greater success in maintaining patients on prescribed therapy.