Loss of skeletal muscle mass after stroke: a systematic review

Loss of muscle mass after stroke has implications for strength and functional ability and may also contribute to impaired glucose metabolism. Therefore, prevention of muscle loss is desirable. Before interventions to prevent loss of muscle can be designed and evaluated, the expected rate, magnitude and timing of muscle loss need to be understood. A systematic search was undertaken to identify all studies that investigated changes in skeletal muscle mass, volume or cross-sectional area in people after stroke. Studies that used either direct measures of muscle size (computer tomography, magnetic resonance imaging or ultrasound) or measures of lean tissue mass (dual X-ray absorptiometry) were included. Fourteen trials were found and the results were pooled for differences in lean tissue mass between the paretic and the nonparetic leg and arm as well as differences in the midthigh cross-sectional area. In individuals at least 6-month poststroke, there was significantly less lean tissue mass in the paretic compared with the nonparetic lower limb (MD 342 center dot 3 g, 95% confidence interval 247 center dot 0-437 center dot 6 g) and upper limb (MD 239 center dot 9 g, 95% confidence interval 181 center dot 7-298 center dot 2 g), and significantly less midthigh muscle cross-sectional area (MD 15 center dot 4 cm2, 95% confidence interval 13 center dot 8-16 center dot 9 cm2). There were insufficient data to pool with regard to change in muscle mass over time. There is a significant difference in the regional muscle mass in the paretic vs. the nonparetic limb in individuals greater than 6-months poststroke but little is known about how early and how quickly changes in muscle mass occur.