Treatment of chronic conditions is associated with a high patient dropout rate within several months of commencing therapy.OBJECTIVE
To evaluate the factors responsible for poor adherence to osteoporosis medication.DESIGN AND INTERVENTION
This was a 12-month, multicenter study of postmenopausal women who had been prescribed pharmacological agents for the treatment of osteoporosis. Medications included calcium and vitamin D supplementation (CaVitD), hormone replacement therapy (HRT), raloxifene (RLX), clodronate (CLOD), risedronate (RIS), daily alendronate (ALN), and weekly alendronate (ALN OW). Eligible participants were referred to an osteoporosis management center for follow-up assessment at least 1 year after commencing treatment. Participants completed questionnaires that assessed demographics, type of osteoporosis drug, other medications, specialization of the prescribing doctor, and time and reason for discontinuation of therapy. BMD was measured by dual energy X-ray absorptiometry or quantitative ultrasound.OUTCOME MEASURE
The main outcome measure was adherence to treatment as a composite of compliance (how the medication was taken) and persistence (time from initiation to discontinuation of treatment).RESULTS
The study enrolled 9,851 women and the mean duration of follow-up was 14 months. Of the participants who underwent BMD measurement, 63.8% had T-scores indicative of osteoporosis at one or more sites. Previous vertebral and non-vertebral fractures were reported by 17.3% and 37.8% of participants, respectively. ALN, RLX or RIS were prescribed in 80% of cases with previous vertebral fracture, whereas 75% of patients with previous hip fracture were treated with ALN or RIS. Overall, ALN was prescribed in 29.8% of cases, and was the drug most frequently prescribed by endocrinologists (40.2%). HRT and RLX were commonly prescribed by gynecologists (51.0% and 16.2%, respectively), whereas CaVitD and CLOD were favored by general practitioners (31% and 35%, respectively). The study discontinuation rate was 19.1%; over half of the discontinuations occurred within 6 months of the initial prescription. CLOD was the most frequently discontinued agent (28.7%), whereas only 6.9% of patients prescribed ALN OW discontinued treatment. The most frequent reasons for discontinuation were adverse effects, lack of motivation and safety concerns, although the prevalence of these factors varied among the different treatment regimens. Treatment persistence was high in patients with previous vertebral fractures, low T-scores, or those who took corticosteroids or anti-inflammatory agents. By contrast, persistence was low in patients who took benzodiazepines or gastro-protective agents, and where BMD measurements were not available. Patients who discontinued treatment displayed poor compliance (≤50%) before dropout. The highest levels of compliance were observed for patients who were prescribed ALN and HRT, and the lowest for CaVitD. Adherence to the prescribed treatment was poor in the patients of general practitioners and orthopedic surgeons.CONCLUSION
The most important determinant of adherence to osteoporosis medication was the type of drug prescribed; the ALN OW regimen was particularly successful.