Three-year experience with alendronate treatment in postmenopausal osteoporotic Japanese women with or without type 2 diabetes

Aims: The increased risk of fractures in patients with type 2 diabetes can partly be explained by poor bone quality and extra-skeletal factors. A retrospective study was conducted to compare the outcome of alendronate (ALN) treatment for 3 years in postmenopausal osteoporotic Japanese women with or without type 2 diabetes. Methods: One-hundred and fifty-one postmenopausal osteoporotic Japanese women (mean age at baseline: 67.8 years) who had been treated with ALN for more than 3 years in our outpatient clinic were analysed. The lumbar spine bone mineral density (BMD) was measured using dual energy X-ray absorptiometry, and the urinary levels of cross-linked N-terminal telopeptides of type I collagen (NTX) and the serum levels of alkaline phosphatase (ALP) were monitored during the 3-year treatment period. The incidence of osteoporotic fractures was also assessed. Results: Sixteen women had type 2 diabetes and were receiving pharmacological treatment, and 135 were non-diabetic. The urinary NTX and serum ALP levels significantly decreased and the lumbar spine BMD significantly increased, compared with the baseline values, without causing any severe adverse events including osteonecrosis of the jaw, femoral diaphysis atypical fractures, and atrial fibrillation, in a manner that was similar among women with type 2 diabetes and non-diabetics. However, the incidence of non-vertebral fractures was significantly higher among women with type 2 diabetes than among the non-diabetics. Conclusions: ALN treatment appeared to have the similar effect on surrogate markers in postmenopausal osteoporotic Japanese women with or without type 2 diabetes. Because of lacking in statistical power for fracture incidence due to the small sample size, further studies are warranted to confirm the results of the fracture incidence.