Adherence to bisphosphonate treatment by elderly women

The aim of this study was to evaluate the relationship between adherence to bisphosphonate treatment by postmenopausal women and demographic, health, and lifestyle factors before treatment in a country with universal subsidies for pharmaceutical costs.

Older women participating in the Australian Longitudinal Study on Women's Health who consented to linkage to Pharmaceutical Benefits Scheme claims data were included if they filled a bisphosphonate prescription between 2002 and 2005 after a medication-free interval of 180 days (N = 788). A Cox proportional hazards model was used to assess the association of baseline variables with duration of adherence to bisphosphonate treatment.

The median time until discontinuation of bisphosphonate treatment was 170 days (95% CI: 154-186). Accounting for socioeconomic status, the baseline variables that were associated with adherence failure were use of acid-related medications (hazard ratio = 1.25, 95% CI: 1.01-1.55) and smoking (hazard ratio = 1.82, 95% CI: 1.26-2.64); reporting high levels of physical activity was associated with better adherence (HR = 0.69, 95% CI: 0.52-0.92).

Overall adherence to bisphosphonate treatment among older Australian women with a fracture history was poor. Inquiring about acid-related disorders and health behavior such as smoking and lack of physical activity could help the prescribing physician to identify women at risk of nonadherence.