Adherence and persistence in patients with severe osteoporosis treated with teriparatide

Introduction: Medical intervention plays a key role in the treatment of postmenopausal osteoporosis and patients' adherence to therapy is essential for optimal clinical outcomes. While adherence in RCTs is usually around 70-90%, a previous study showed that in clinical practice only 27.8% and 46.5% of the women on oral daily vs. weekly alendronate were still on treatment after 12 months. Data on adherence to teriparatide (TPTD) treatment of severe postmenopausal osteoporosis are available from only few countries. This study assessed adherence and persistence with TPTD in Germany. Material and methods: A sample of 50 women with severe postmenopausal osteoporosis treated with TPTD in accordance to the German osteoporosis guidelines was included. Treatment was initiated 12-24 months before recruitment. Patient self report was assessed using a validated questionnaire. In addition medication possession ratio (MPR) was calculated by counting prescription refills, and therefore all physicians who were treating the patients for any disease were contacted. Patients were classified adherent at 12 months of therapy if self-reported adherence and an MPR of >= 80% were achieved. Persistence was calculated in months and analysed with a Kaplan-Meier estimate. Results: Apart from a significantly lower age at menopause in the adherent group (46.1 vs. 50.0; p<0.006) there were no significant differences in baseline demographics between adherent and non-adherent patients. After 12 months, 80% of the patients treated with TPTD were adherent, while 20% were non-adherent. A significant correlation with treatment adherence was found for self-reported medication tolerability (p<0.001). Furthermore 79% of patients were persistent after 12 months. Conclusion: These results indicate that more patients seem to be adherent and persistent with TPTD than with oral treatments of postmenopausal osteoporosis. As these patients suffered from severe osteoporosis and sustained several fragility fractures, the generalisability of our retrospective study analysing a small sample is limited. The major factor that reduced adherence and persistence was tolerability. These findings are of practical relevance as numerous studies on antiresorptive therapies have shown that high adherence and persistence were needed to ensure an optimal therapeutic outcome.