Secondary Hyperparathyroidism Is Associated with Increased Risk of Hospitalization or Death in Elderly Adults Living in a Geriatric Institution

BACKGROUND: The presence of secondary hyperparathyroidism is very frequent in the elderly population living in geriatric institutions. It has been associated with an increased mortality rate in previous studies. OBJECTIVES: To evaluate the association of secondary hyperparathyroidism with mortality or hospitalization or both (combined outcome) during a 6-month period in individuals living in geriatric institutions. METHODS: A cohort of 100 individuals aged between 65 and 102 years living in geriatric institutions in the city of Porto Alegre, Brazil, was prospectively studied. Serum levels of 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), albumin, total calcium, phosphorus, magnesium, creatinine and alkaline phosphatase were measured. The glomerular filtration rate (GFR) was calculated using the Cockcroft-Gault equation. Secondary hyperparathyroidism was defined as serum PTH levels higher than 48 pg/ml and normal or reduced serum calcium levels. The deaths were verified by means of death certificates and hospitalization by the discharge summaries provided by the Brazilian health system hospitals. RESULTS: Fifty-eight percent of the individuals had secondary hyperparathyroidism, defined as serum PTH >48 pg/ml and normal or low serum calcium. Mean serum 25(OH)D levels were 12.5 +/- 8 ng/ml. The odds ratio of an individual with secondary hyperparathyroidism to die, to be hospitalized or to have the combined outcome within 6 months was 6.6 [confidence interval (CI) 95% 0.8-54.6; p = 0.07], 10.7 (CI 95% 1.3-85.9; p = 0.007) and 5.20 (CI 95% 1.10-27.7; p = 0.04), respectively. Secondary hyperparathyroidism and body mass index were independently associated with the combined outcome, after correction for the GFR and 25(OH)D. CONCLUSION: Secondary hyperparathyroidism could be an important prognostic factor for individuals living in geriatric institutions.