Adherence to osteoporosis therapy after an upper extremity fracture: a pre-specified substudy of the C-STOP randomized controlled trial

Despite their proven efficacy for secondary fracture prevention, long-term adherence with oralbisphosphonates is poor.IntroductionTo compare the effectiveness of two interventions on long-term oralbisphosphonate adherence after an upper extremity fragility fracture.MethodsCommunity-dwelling participants 50years or older with upper extremity fragility fractures not previously treated with bisphosphonates were randomized to either a multi-faceted patient and physician educational intervention (the active control arm) vs. a nurse-led case manager (the study arm). Primary outcome was adherence (taking >80% of prescribed doses) with prescribedoral bisphosphonates at 12months postfracture between groups; secondary outcomes included rates of primary non-adherence and 24-month adherence. We also compared quality of life between adherent and non-adherent patients.ResultsBy 12months, adherence with the initially prescribed bisphosphonate was similar (p=0.96) in both groups: 38/48 (79.2%) in the educational intervention group vs. 66/83 (79.5%) in the case manager arm. By 24months, adherence rates were 67% (32/48) in the educational intervention group vs. 53% (43/81) in case managed patients (p=0.13). Primary non-adherence was 6% (11 patients) in the educational intervention group and 12% (21 patients) in the case managed group (p=0.07). Prior family history of osteoporosis (aOR 2.1, 95% CI 1.0 to 4.4) and being satisfied with current medical care (aOR 2.3, 95% CI 1.1 to 4.8) were associated with better adherence while lower income (aOR 0.2, 95% CI 0.1 to 0.6, for patients with income <$30,000 per annum) was associated with poorer rates of adherence. There were no differences in health-related quality of life scores at baseline or during follow-up between patients who were adherent and those who were not.ConclusionWhile both interventions achieved higher oral bisphosphonate adherence compared to previously reported adherence rates in the general population, primary non-adherence and long-term adherence to bisphosphonates were similar in both arms. Adherence was influenced by family history of osteoporosis, satisfaction with current medical care, and income.Trial registrationClinicalTrials.gov: NCT01401556