Primary hyperparathyroidism in elderly patients with hip fracture.

Primary hyperparathyroidism (PHPT) is associated with low bone mineral density (BMD), but its association with fractures is controversial. Our aim was to evaluate the prevalence of PHPT in hip fracture patients. We studied 444 of 450 consecutive elderly patients (404 women and 40 men) admitted to a rehabilitation hospital after hip fracture. All the fractures were either spontaneous or sustained as a result of minimal trauma. The diagnosis of PHPT was established when both serum calcium adjusted for serum albumin exceeded the normal range and PTH was either elevated or high normal. Also, 444 sex-matched subjects, aged 65 years and older, who were referred for their first osteodensitometry, were studied as controls. Among the hip fracture patients, 21/444 (i.e., 4.7%) fulfilled the diagnostic criteria of PHPT. Logistic multiple regression showed no meaningful associations between PHPT and sex, age, weight, height, fracture type (cervical or trochanteric), and femoral BMD in the hip fracture patients. Among the 444 controls, 5 patients (i.e., 1.13%) fulfilled the diagnostic criteria of PHPT. When evaluated by Pearson's chi-square, the difference in PHPT prevalence between the hip fracture patients and the controls was significant ( P < 0.01). Data show that the prevalence of PHPT in a sample of elderly patients after hip fracture was increased when compared to that found in a sample of control subjects, suggesting that PHPT enhances hip fracture risk.