Adherence to oral bisphosphonates: 30 more minutes in dosing instructions matter

Abstract

Objectives Low adherence to treatment with bisphosphonates significantly impedes its effectiveness. The objectives were: (1) to compare adherence to oral weekly and monthly bisphosphonates with emphasis on dosing instructions; and (2) to study associations between adherence and beliefs about the bisphosphonate treatment among women ≥ 55 years.

Methods A multicenter survey was performed in secondary-care patients with osteoporosis. Osteoporosis Specific Morisky Medication Adherence Scale (OS-MMAS), questions on compliance with five dosing instructions and Beliefs about Medicines Questionnaire (BMQ) Specific were used.

Results As many as 363 questionnaires (response rate 95%) were analyzed. Respondents (mean age 69 years) were treated with weekly bisphosphonates (37%) or monthly ibandronate (63%). Based on OS-MMAS, 67% of respondents showed high adherence with no differences between the subgroups. Only 44% of respondents were compliant with all dosing instructions. Compliance with dosing instructions concerning time interval (fasting and staying upright) was 71% in weekly and 52% in monthly subgroups, respectively (p < 0.001). Compliance with dosing instructions correlated positively with education (p = 0.009). The mean BMQ necessity score of 18.4 was greater than the mean BMQ concerns score of 13.3. OS-MMAS score correlated with necessity (p = 0.010). Persistence derived from OS-MMAS correlated with both necessity (p = 0.014) and concerns (p = 0.041).

Conclusion Despite relatively high adherence to the treatment, most patients do not follow dosing instructions. Reduced bioavailability, particularly of monthly ibandronate, can be expected in clinical practice. Adherence-related outcomes are associated with beliefs about the oral treatment with bisphosphonates.

Key words::

• OSTEOPOROSIS
• MEDICATION ADHERENCE
• DOSING INTERVAL
• DOSING INSTRUCTIONS
• ORAL BISPHOSPHONATES
• NECESSITY-CONCERNS FRAMEWORK

ACKNOWLEDGEMENTS

The authors would like to thank students of the Faculty of Pharmacy in Hradec Kralove, the nursing staff of the participating centers for their assistance with data collection and Michal Urbanek, MSc for English editing. The authors also express their thanks to Professor Donald E. Morisky who gave the permission for use of the OS-MMAS for the study purposes.

Conflict of interest The authors report no conflict of interest. The authors alone are responsible for the content and writing of this paper.

Source of funding The study was supported by Charles University in Prague, the project SVV 260 066, and Ministry of Health, Czech Republic, the project for conceptual development of research organizations MH CZ – DRO: UHHK, 00179906.