Serum Cathepsin-K as Potential Biomarker in Pre and Postmenopausal Osteoporosis Interaction with Diabetes Mellitus and Metabolic Correlates

Abstract

Osteoporosis is a disease of the skeletal system that results from a decrease in bone density and quality, which weakens bones and causes fragility fractures. The objectives of the study are to estimate the level of serum cathepsin K in pre- and post-menopausal women with osteoporosis compared with DM. A total of 100 women aged 40>60 years were recruited for this case control study and were divided into 5 groups according to menopausal status and diabetes status (with and without diabetes) and a healthy control group. Serum Cathepsin K levels were determined, bone mineral density (BMD) was evaluated by DXA scan, and insulin resistance was measured as fasting blood glucose and insulin levels, and then estimated by HOMA-IR. All osteoporotic groups had significantly higher serum Cathepsin K levels than healthy controls (p < 0.01). An association was found between BMI and Cathepsin K level, only in premenopausal diabetics (p < 0.01). The diagnostic value of Cathepsin K was evaluated using receiver operating characteristic (ROC) curve analysis, showing an area under the curve (AUC) of 0.971, 83% sensitivity and 95% specificity at the threshold of 2.167 ng/mL. The results of this study have confirmed the promise of Cathepsin K as a valuable, sensitive and reliable bone-loss marker for the diagnosis of osteoporosis. In women with osteoporosis, there is a higher level of Cathepsin K in the serum, which suggests higher levels of bone resorption activity. These results indicate that it could be a useful and sensitive biomarker for diagnosis of osteoporosis.