Bone loss after stroke over 52 weeks at os calcis: influence of sex, mobility and relation to bone density at other sites

Background: as life expectancy increases after stroke, skeletal consequences become increasingly important, and patients at risk of fracture require identification. We have investigated peripheral bone mineral density (BMD) measurement at the heel as a possible surrogate for hip dual energy X-ray absorptiometry measurement and we have related bone loss over 52 weeks to balance and mobility. Methods: BMD at the heel (PIXI), proximal femur and whole body (QDR4500A), Tinetti (a measure of mobility and balance) and Barthel (a measure of activities of daily living) scores were measured in 52 patients (27 males and 25 females) within 8 weeks of stroke and repeated in 27 (15 males and 12 females) after 52 weeks. Results: BMD was not initially low at the femoral neck (FN). A significant fall occurred on the stroke side (SS) over 52 weeks at the heel, FN and total hip (TH), in both sexes, but was greater in women. On the non-SS, women lost bone at the TH and heel. Patients who were in the lowest Tinetti score tertile initially, showed significant loss of bone in the FN (14.5%) and at the heel (12.2%) on the SS. BMD at the SS heel correlated with the FN at 8 weeks (r = 0.64, P < 0.01) and at 52 weeks (r = 0.60, P < 0.01) after stroke. Women lost more bone than men on SS but also lost bone on the non-SS at the same sites, suggesting that SS bone loss may result from factors additional to stroke. Conclusion: heel BMD was a useful surrogate for hip BMD. Low initial Tinetti scores were an indicator of bone loss and, together with initial BMD measurements, provide a useful indication for those needing early prophylaxis against bone loss.