A study published in the Journal of Clinical Endocrinology & Metabolism has investigated whether rosiglitazone inhibits bone formation. This small 14-wk randomised, double-blind, placebo-controlled trial included 50 otherwise healthy postmenopausal women who received rosiglitazone 8mg/day. The women were included if they were more than 5 year post-menopausal, and aged older than 55 years.
The primary end points of the study were the two specific markers of bone formation, osteocalcin and procollagen type-I N-terminal propeptide (P1NP). The researchers reported that the osteoblast markers P1NP and osteocalcin declined by 13% (P < 0.005 vs. placebo) and 10% (P = 0.04 vs. placebo), respectively, in the rosiglitazone group. These changes were evident by 4 weeks and persisted for the duration of the study.
From these preliminary findings, they concluded that short-term therapy with rosiglitazone may have detrimental effects on bone formation, and advise that skeletal end points should be included in future long-term studies of thiazolidinedione use.
[Editor's comment: both rosiglitazone and pioglitazone were the subject of FDA warnings to US health professionals recently, noting an increased risk of fractures in women taking these drugs during trials compared to comparator drugs. This paper provides some theoretical support to the trial data.]
J Clin Endocrinol Metab 2007; 92: 1305-10 (link to abstract).