Hormone Replacement Therapy in Postmenopausal Women: Urinary N-Telopeptide of Type I Collagen Monitors Therapeutic Effect and Predicts Response of Bone Mineral Density

Abstract PURPOSE: To assess the ability of the urinary N-telopeptide of type I collagen (NTx) to monitor and predict therapeutic effects of hormone replacement therapy (HRT) in postmenopausal women. PATIENTS AND METHODS: To assess the relationship between baseline or change in NTx (predictive variable), and change in lumbar and hip bone mineral density (BMD; outcome variable), we conducted a 2-year randomized controlled study at academic university and private practice medical centers in 236 healthy women 1 to 3 years postmenopausal; 227 women completed the study. Women received estrogen plus progesterone plus calcium (treated group) or calcium alone (control group). RESULTS: In the treated group NTx significantly ( P P P P P P 67 units) indicated a 17.3 times higher risk of BMD loss if not treated with HRT. CONCLUSION: These data support the clinical utility of NTx to monitor the antiresorptive effect of HRT in recently postmenopausal women, and to predict changes in BMD in response to HRT.