Determination of precipitated primary non-adherence after step therapy intervention in 4 classes of therapy

Abstract

In light of drastically escalating costs for today’s medications, pharmacy benefit managers are seeking a constant balance of effectiveness and cost control. Step Therapy helps to address these concerns with a try medication “A” before medication “B” logic. Like all medical interventions, the possibility of unintended consequences exists. The purpose of this study was to determine if non-adherence results from application of Step Therapy for selected medication classes (antihyperlipidemics (specifically the HMG Co-A reductase inhibitors), angiotensin receptor blockers, uro-selective alpha-blockers, and dipeptidyl peptidase-4 inhibitors) in the Department of Defense. Using a retrospective database analysis, this study examined the primary adherence rate of subjects after they have been denied coverage due to Step Therapy intervention. Additionally, this study examined the association of demographic and service-related factors with the likelihood that a patient will be non-adherent after encountering the intervention. Finally, the study measured the time to adherence after intervention for those who were persistent after a Step Therapy claim rejection. STATA version 10.0 was used to conduct logistic regression analyses to meet the study objectives. After examination of 279,508 claims for 27,202 subjects, the estimated primary non-adherence rate following the Step Therapy intervention for all medication classes combined was 15.1%. Additionally, there was inter-class variability in this rate ranging between 13.1% and 19.5%. A statistical and practical difference was also noted in non-adherence rates between subjects who received care at the retail point of service versus those who received care at the mail order point of service. Subjects who received care through retail were nearly twice as likely to be non-adherent as those who received care in the mail order segment. For those subjects who were persistent with therapy, the median time-to-fill was estimated at 7 days. The occurrence of non-adherence following a Step Therapy intervention was clearly demonstrated through this study. Although this study provides good framework for designing interventions after claim rejection, further research would help to determine the health impact of primary non-adherence as well as the economic consequences of the intervention.