Bone Mineral Density in Patients With Stroke: Relationship With Motor Impairment and Functional Mobility

Abstract

Purpose: Patients with stroke have a 2- to 4-fold increased risk of hip fracture compared to the general population, because of decreased bone mineral density (BMD) on the paretic side and the high incidence of accidental falls. However, the relationship between BMD and stroke-related motor impairment and functional mobility is not known. The purpose of this study was to investigate these relationships. Method: A convenience sample of 87 patients with stroke was recruited from an outpatient rehabilitation clinic. Demographics and clinical history were collected, and patients answered questionnaires regarding functional status. Motor impairment was assessed using motor items of the National Institutes of Health Stroke Scale (NIHSS), and BMD was measured using dual energy X-ray absorptiometry. Results: Mean BMD measured at the total hip was lower on the paretic side relative to the contralateral side (0.883 ± 0.148 g/cm² vs 0.923 ± 0.136 g/cm²; P < .001). Compared to patients without limitations in walking, those reporting limitations had lower BMD at the paretic total hip (0.808 ± 0.141 g/cm² vs 0.917 ± 0.139 g/cm²; P = .001) and lower BMD Z scores (–0.282 ± 0.888 vs –0.028 ± 0.813; P = .035). A significant correlation was found between mean BMD and the BMD Z score at the total hip on the paretic side and motor impairment in that lower extremity (r = –0.326, P = .003; r = –0.312, P = .004, respectively). Conclusion: In patients with stroke, BMD at the paretic hip correlated with motor impairment. Furthermore, ability to ambulate was shown to be a simple yet useful test to determine which individuals had increased bone loss at the paretic versus nonparetic hip.

Keywords:

• bone mineral density
• motor function
• stroke