Summary

Background: The treatment of osteoporosis among postmenopausal women represents a major public health challenge since long-term therapy is needed to prevent fractures and chronic disability.

Objectives: To assess compliance with osteoporosis drug therapy among Israeli postmenopausal women treated with either a bisphosphonate (alendronate) or a selective estrogen receptor modulator (raloxifene); to identify factors affecting compliance among these patients; and to compare adherence to the treatment in these two groups.

Methods: Our study included 178 consecutive patients aged 67.41 ± 8.52 years who were treated for osteoporosis with alendronate or raloxifene in the Metabolic Bone Diseases Unit. All the patients received supplement with calcium carbonate 1,500 mg and 600 IU vitamin D daily. Compliance was assessed at a clinic visit 6 months after starting therapy.

Results: The dropout rate was 23% (41 patients): 20 patients (31%) in the raloxifene group and 21 (18%) in the alendronate group (P = 0.0041). The main reasons for dropout were side effects and/or non-compliance, 16 and 24 patients (39% and 58.53%), respectively. The most frequent side effect was abdominal pain in 9 patients (42.8%) who discontinued alendronate use. The reasons for non-compliance were a fear of side effects and high drug price in 6 (30%) and 4 (20%) patients respectively in the raloxifene group, and inconvenience caused by medication use in 3 (14.3%) patients in the alendronate group. Logistic regression analysis of factors that may influence compliance included age, previous fractures, family history of osteoporosis, bone density T-score less than -2.5, and presence and number of concomitant diseases. Age was the only statistically significant parameter in this model: 67.8 ± 8.8 in non-compliant versus 64.11 ± 7.4 in compliant patients (P = 0.029).

Conclusion: At least 20% of the patients discontinued chronic treatment for osteoporosis during the initial 6 months of therapy. The main reasons were gastrointestinal side effects in the alendronate group, and fear of side effects and high drug price in the raloxifene group. Older age was the only statistically significant factor influencing compliance.