Patients who have had a stroke are prone to falls and therefore to fractures, which significantly increases their morbidity and mortality. Osteoporosis in this population is already an important clinical problem, and immobilization has been shown to increase the risk for osteoporosis. Multiple studies have evaluated bone mineral density (BMD) in patients who have had a stroke, but none has assessed multiple sites or impact over time. Liu and associates measured BMDs using a dual-energy x-ray absorptiometry (DXA) scan in hemiplegic stroke patients, comparing BMDs on the affected and unaffected sides. They also recorded changes in BMD in these patients over a three-month period of rehabilitation.
Patients admitted to a tertiary rehabilitation unit with left-sided brain injury after a stroke were enrolled in the study. BMD was measured using the DXA scan at the proximal humerus, the distal radius, the femoral neck, the calcaneus bilaterally and the third lumbar vertebra. Affected and unaffected sides were measured on admission and after three months of therapy. Patients were also evaluated with other standard stroke assessment tools to assess physical improvements at admission and before discharge. Basic demographic information was recorded as well.
A total of 104 patients participated in the study. On admission, the average BMDs on the affected and unaffected sides were 88.3 and 98.4 percent, respectively. Before discharge, BMDs were 79.6 and 98.8 percent. The greatest loss of bone density occurred at the humerus on the affected side. The physical performance of all patients significantly improved by the end of rehabilitation. Other variables such as advancing age, female gender, body weight and height, and lower scores on physical assessment scales contributed differently to BMD scores.
The authors conclude that BMD is decreased on the hemiplegic side following a stroke, particularly in the upper extremity on the affected side. This loss of bone density also occurred over time. More research is needed to better identify treatment options for these patients.
editor's note: Prevention of osteoporosis is a key consideration in any management plan for postmenopausal women. Unfortunately, other risk factors for osteoporosis are not recognized and are often left untreated. In this study, patients who had suffered a stoke showed significant bone loss on the affected side, particularly in the upper extremity. This finding correlates with our knowledge that immobilization causes bone loss. Although the authors do not address treatment, these patients would probably benefit from correction of any other risk factors. Treatment options should be explored in patients with significant bone loss to prevent potential fractures that add to morbidity and mortality.—k.e.m.