Secondary hyperparathyroidism in patients from Western Australia with hip fracture: relationship to type of hip fracture, renal function, and vitamin D deficiency.

Abstract

To determine the frequency of vitamin D deficiency and secondary hyperparathyroidism in Australian hip fracture patients living in the community. A total of 283 consecutive patients with hip fracture admitted over a 15-month period to a university teaching hospital in Western Australia. Included were residents of hostels for the elderly, and excluded were nursing home residents and those with malignant fractures. Data collected included biochemistry (25 hydroxyvitamin D, parathyroid hormone and creatinine levels), measurements of function and disability (Barthel Index, Frenchay Activity Index), sunshine exposure, and basic demographics. Vitamin D deficiency occurred in 31.7% and secondary hyperparathyroidism occurred in 17.7% of cases. The major determinants of vitamin D deficiency were outdoor sunshine exposure, ambient daily sunshine, and disability (low Frenchay Activity Index or ADL difficulty). Secondary hyperparathyroidism was related to older age, renal dysfunction, and vitamin D deficiency. Secondary hyperparathyroidism was associated with an excess of trochanteric over subcapital hip fractures. Secondary hyperparathyroidism appears to be a heterogeneous condition, caused in approximately equal proportions by vitamin D deficiency and renal dysfunction, that may confer increased cortical bone fragility and trochanteric fractures. Renal dysfunction in old age may be an important additional determinant of senile osteoporosis, which has implications for preventive therapy. Vitamin D deficiency occurs in disabled and, presumably, housebound older people despite near optimal climatic conditions.