Influence of immobilization upon calcium metabolism in the week following hemiplegic stroke

Hip fractures on the paretic side are a serious post-stroke complication an d may result from disuse hemiosteopenia, hypovitaminosis D, and an increasi ng risk of falls. To evaluate short-term immobilization effects, we assesse d calcium metabolism in 89 patients 1 week after the hemiplegic stroke and in 36 controls. Patient activity was rated using the Barthel index (BI). Se ra from stroke patients and control subjects were assayed for ionized calci um, parathyroid hormone (PTH), 25-hydroxyvitamin D (25-OHD), 1,25-dihydroxy vitamin D (1,25-(OH)(2)D), bone Gla protein (BGP; a bone formation marker) and pyridinoline cross-linked carboxy-terminal telopeptide of type I collag en (ICTP; a bone resorption marker). Patients' serum concentrations of ioni zed calcium and ICTP were higher than in controls and correlated negatively with BI; their BGP concentrations were low, correlating positively with BI . Concentrations of serum 25-OHD, 1,25-(OH)(2)D, and PTH also were low; ser um 25-OHD was at a deficient level (<10 ng/ml) in nine patients (10%), an i nsufficient level (10-20 ng/ml) in 56 (63%), and a sufficient level (>20 ng /ml) in only 24 (27%). PTH correlated negatively with calcium and 1,25-(OH) (2)D. Hypovitaminosis D is common in acute stroke patients. Immobilization from acute hemiplegia can increase bone resorption and serum calcium, and i nhibit PTH secretion and 1,25-(OH)(2)D production to add to the effects of hypovitaminosis D. (C) 2000 Elsevier Science B.V. All rights reserved.