Prior adherence to statins is a predictor of subsequent adherence and persistence to oral, but not parenteral, osteoporosis medications.

Abstract

Although bisphosphonates are effective for treating osteoporosis, patient adherence is variable. We conducted this study to determine if prior adherence with another medication used to treat chronic asymptomatic conditions predicts adherence with bisphosphonates. Retrospective cohort study using linked population-level data for the entire Canadian province of Alberta between April 1, 2009 and March 31, 2017. We examined all new users of an oral or parenteral osteoporosis treatment over the age of 20 who had filled at least one statin prescription in the prior 12months before the start date of the osteoporosis treatment. Adherence was defined based on medication possession ratio (MPR) and > = 80% was deemed good adherence. Persistence was defined as continuous treatment without an interruption of treatment for more than 56days. Of 20,612 new users of oral bisphosphonates and 1538 new users of parenteral treatments, prior good adherence with statins was independently associated with both short term [adjusted Odds Ratio (aOR) 1.34 (95% CI 1.26-1.42) at 1year] and long term [aOR 1.35 (1.20-1.51) at 5years] adherence with oral bisphosphonates. However, there was no association between prior statin adherence and adherence [OR 0.94 (0.74, 1.20)] or persistence [(OR 0.96 (0.76, 1.22)] with parenteral osteoporosis therapies. Other factors associated with oral bisphosphonate adherence at 1year included older age, history of bone mineral density scan, and history of pap smear. Prior adherence to statins is a predictor of subsequent short-term and long-term adherence and persistence with oral bisphosphonates but not parenteral osteoporosis therapies.