Persistence to medical treatment of osteoporosis in women at three different clinical settings - A historical cohort study

Purpose: This study was undertaken to assess persistence with bisphosphonates and raloxifene and to identify determinants of adherence (patient age, level of information, educational status, etc.) among women with osteoporosis in three different clinical settings in Denmark. Methods: We compared persistence to therapy in three historical cohorts of women diagnosed with osteoporosis starting therapy between January 1999 and January 2004. The study comprised 878 patients treated and followed at Odense University Hospital, 285 patients diagnosed and followed at the Hellerup Osteoporosis Clinic (private practice), and 343 patients diagnosed at Aarhus University Hospital and followed by the referring general practitioner. Data on persistence and possible confounders were collected using a mailed questionnaire. Reminders were issued after 1-2 months to non-respondents. Results: Persistence at 2 years as estimated from Kaplan-Meyer analysis was 0.87, 0.84 and 0.88 in the three cohorts, respectively. There were no significant differences between the clinics. Level of persistence was not related to patient assessment of the adequacy of the clinical information provided by the prescribing doctor, presence of prior fractures or a family history of osteoporosis. However, patients who read the information leaflet on their osteoporosis medication tended to be more persistent with treatment (p<0.09). Conclusions: Women's persistence with bisphosphonates and raloxifene was surprisingly high and similar between treating centres. This may be due to a high level of public information available on osteoporosis in Denmark.