Objective The use of
thiazolidinediones is reported to be associated with an increased frequency of fractures, especially in women; however, the underlying mechanism is not clear. In this prospective study, we compared the effects of
pioglitazone and
metformin on bone metabolism in Japanese patients with
type 2 diabetes mellitus. Methods A total of 58 patients with
type 2 diabetes (24 men and 34 women) were randomly assigned to receive either
pioglitazone (30 and 15 mg/day for men and women, respectively) or
metformin (750 mg/day). The changes in serum and urinary type 1 cross-linked
N-telopeptide (NTX), type 1 cross-linked
C-telopeptide (CTX), bone
alkaline phosphatase (BAP),
homocysteine, and serum
pentosidine were evaluated before and after three months of treatment. The primary endpoint was changes in
bone resorption markers after three months. Patients The subjects of this research were male and female
type 2 diabetes patients, less than 80 years of age. Results
Pioglitazone significantly increased the serum and urinary NTX and serum and urinary CTX levels. The rates of changes in the serum and urinary NTX and CTX were significantly greater in the
pioglitazone group than in the
metformin group. Although the BAP levels decreased significantly in the
pioglitazone group, the rates of change were similar between the two groups. In the
pioglitazone group, the changes in fasting
insulin levels correlated significantly with increased
bone resorption, independent of age and gender. Conclusion The results demonstrated that
pioglitazone increased
bone resorption independent of age and gender in Japanese patients with
type 2 diabetes.