IMPAIRMENT OF BONE TURNOVER IN ELDERLY WOMEN WITH HIP FRACTURE

Hip fracture is one of the most severe consequences of osteoporosis af fecting aged women. However, abnormalities of bone turnover responsibl e for bone loss in this condition have not been clearly defined. To fu rther evaluate the bone metabolic status of women sustaining hip fract ure, we have prospectively measured serum osteocalcin as a marker of b one formation and urinary excretion of pyridinoline (Pyr) and deoxypyr idinoline (D-pyr) cross-links as markers of bone collagen degradation in 174 independently living women (80 +/- 8 years) within a few hours after a hip fracture. Comparison was made with 77 age-matched controls (80 +/- 5 years) and 17 premenopausal women (39 +/- 3 years). In addi tion 15 of the patients were followed with daily measurements during t he first postoperative week. At the time of admission osteocalcin was 20% lower in the fractured women compared to the elderly controls (7.6 +/- 3.8 vs. 9.5 +/- 4.5 ng/ml, P = 0.001). Pyr and D-pyr were 36% and 40% higher, respectively (P = 0.0001), than in elderly controls and 8 5% and 76% higher than in premenopausal controls (P = 0.0001). Serum o steocalcin did not correlate with the cortisol level measured at the s ame time (r = 0.03, ns), nor with serum albumin and creatinine. Serum osteocalcin remained unchanged within 18 hours after fracture, whereaf ter it progressively decreased until the third postoperative day. No c orrelation was noted between the excretion of pyridinoline cross-links and the time elapsed from fracture. These data suggest that the abnor mal levels of osteocalcin and pyridinolines are unrelated to traumatic ally induced acute changes, but reflect abnormalities of bone turnover existing prior to the fracture. Thus, hip-fracture patients have bioc hemical evidence of decreased bone formation and increased bone resorp tion when compared to age-matched controls. We suggest that these abno rmalities may play a role in the decrease of the bone mass and the con sequently increased bone fragility that characterize the osteoporotic hip fracture in the elderly.