Skeletal muscle function in chronic renal failure: an index of nutritional status

To determine whether skeletal muscle function testing (SMF) provides an index of nutritional status in patients with chronic renal failure (CRF), two groups with comparable CRF were studied. In 48 well-nourished (WN) and 17 malnourished (MN) patients with stable CRF, and in 33 WN nonazotemic controls, adductor pollicis function was assessed. The force at 10 Hz was expressed as a % of force at 100 Hz (F10/F100), and maximal relaxation rate (MRR) as % force loss/10 ms. Standard nutritional assessment was also performed. The WN group was not significantly different from controls for either F10/F100 or MRR. The F10/F100 of the MN group was significantly greater than either the WN group or controls (p less than 0.001), while MRR was less (p less than 0.001). Significant malnutrition by conventional parameters was shown in patients with abnormal F10/F100, and also in patients with abnormal MRR. Hence, SMF as described is unaffected by azotemia, and provides a functional measure of nutritional status in CRF.