Intramuscular Fat Content and the Risk of Peritonitis in Peritoneal Dialysis Patients

Background Sarcopenia is a common and serious complication of dialysis patients. In addition to the reduction in total muscle mass, fat infiltration of skeletal muscle as represented by the percentage of intermuscular adipose tissue (IMAT%), affects muscle quality and may have prognostic implications. Methods We investigated 86 incident peritoneal dialysis (PD) patients. Their total muscle area, skeletal muscle index, and IMAT% at the level of third lumbar vertebra (L3) was measured by computer tomography. The relation with functional assessment, bioimpedance spectroscopy (BIS) parameters, survival, and peritonitis rate were analyzed. Results L3 total muscle area and IMAT% had opposite but both significant correlation with functional scores Morse Fall Scale and Norton Scale) and lean tissue mass (LTM) measured by BIS, but IMAT% did not have correlation with adipose tissue mass by BIS. IMAT%, but not total muscle area, was independently associated with peritonitis-free survival (adjusted hazard ratio 1.084, 95% confidence interval (CI) 1.027 to 1.144, p = 0.004) and peritonitis rate (adjusted β = 1.091, 95% CI 1.032 to 1.155, p = 0.002). Neither total muscle area nor IMAT% was associated with patient survival or hospitalization rate. Conclusion IMAT% is an independent predictor of peritonitis-free survival and peritonitis rate in incident PD patients. Further studies are needed to validate our result and to develop convenient non-invasive methods for the assessment of IMAT%.