Urinary pyridinoline and deoxypyridinoline as bone metabolic markers in predicting therapeutic effects of estrogen and alfacalcidol in women with osteoporosis.

The purpose of the present study was to evaluate the clinical usefulness of urinary pyridinoline (Pyr) and deoxypyridinoline (Dpyr) in predicting therapeutic effects of estrogen and alfacalcidol (1α-D3) in patients with postmenopausal osteoporosis. We measured urinary excretion of Pyr and Dpyr, and determined bone mineral density (BMD) using a dual-energy x-ray absorptiometry in 48 women with osteoporosis (average age, 55.9 ± 8.4 years). Patients were treated with estrogen (HRT, n = 13), 1α-D3 (n = 20), or calcium alone (n = 15). Baseline mean levels of urinary Pyr and Dpyr were significantly higher in the 48 patients compared to those in the age-matched postmenopausal women. The levels of urinary Pyr and Dpyr were inversely correlated with BMD. After treatment with estrogen or 1α-D3, a significant decrease of urinary Pyr and Dpyr was observed, and elevated urinary Pyr and Dpyr were reduced to the level in premenopausal women. A significant inverse correlation was found in Pyr and Dpyr at 6 months and in lumbar BMD after 24 months of treatment (r = −0.43 to −0.52; P < 0.01). We concluded that urinary Pyr and Dpyr have clinical utility for predicting response to estrogen and 1α-D3 therapy of osteoporosis patients.