Endocrine Abstracts

Background: Denosumab (Dmab) is a human monoclonal antibody with an anti-reabsorptive bone effect, used in osteoporosis treatment. It is also suggested that Dmab may improve glucose tolerance through the reduction of hepatic insulin resistance. Some studies have suggested that insulin sensitivity and glycemia can influence bone metabolism.

Aims: To evaluate the relationship between bone turnover markers (BTM) and insulin resistance and glycemia in fracturary osteoporotic patients treated with Dmab.

Methods: Retrospective study of a cohort of osteoporotic patients treated with Dmab for at least 6 months. BTM (CTX - serum C-telopeptide of type I collagen, P1NP - serum procollagen type 1 N-terminal propeptide, BALP - bone alkaline phosphatase and osteocalcin), fasting glycemia and insulin were measured at baseline (T0) and after Dmab treatment (T1). Insulin resistance was estimated using homeostasis model assessment of insulin resistance (HOMA-IR) at T0 and T1. Adequate statistical studies were used, statistical significance was considered for P<0.05. Results are expressed as mean±SD.

Results: Included 18 patients, 15 postmenopausal women and 3 men, with a mean age 75.5±9.1 years old, treated with Dmab for 23.7±10.1 months. It was observed a reduction of BTM levels after Dmab (BTM T0 vs T1 were: CTX 0.35±0.18 vs 0.14±0.13 ng/ml, P<0.01; P1NP 43.7±16.0 vs 21.1±9.7 ng/ml, P<0.01; BALP 13.9±5.2 vs 8±2.0 µg/l, P<0.01; osteocalcin 17.9±6.9 vs 10.0±4.0 ng/ml, P<0.01). After Dmab (T0/T1), fasting glycemia (98.6±23.6/93.6±18.5 mg/dl, P=0.04), fasting insulin (10.8±5.3/9.4±4.8 µU/ml, P=0.1) and HOMA-IR (2.5±0.5/2.3±1.4, P=0.43) decreased. There were no associations between HOMA-IR, insulin or glycemia and each BTM at T0 and T1.

Conclusions: In this group of fracturary osteoporotic patients, Dmab reduced significantly BTM and glycemia. These results may suggest that Dmab can be a good option treatment for patients with diabetes and insulin resistance, both known factors contributing to osteoporotic fractures. Studies with more patients can validate these preliminary results.