Comparison of bioimpedance analysis and dual-energy x-ray absorptiometry in peritoneal diaysis patients according to edema

The change in difference between bioimpedance analysis (BIA) and dual-energy X-ray absorptiometry (DEXA) according to edema is an important issue for peritoneal dialysis (PD) patients. We reviewed all adults who received PD. Patients had undergone two body composition measurements. 1108 cases were measured simultaneously by BIA and DEXA. Measurements were divided into four quartiles based on edema index. There were significant correlations and intraclass correlations between the two methods for lean mass (LM), fat mass (FM) and bone mineral content. On a simple linear regression analysis, non-standardized-βs of total LM decreased as the grade of edema index increased (from 1.008 to 0.949). Those of total FM were increased as the grade of edema index increased (from 1.034 to 1.162). Bias for total LM changed to negative and negative bias increased as the grade of edema index increased (from 0.406kg to –2.276kg). There was a positive bias for total FM in first quartile and increased as the grade of edema index increased (from 0.594kg to 2.863kg). In conclusion, the present study demonstrates that BIA can measure normal hydrated LM in CAPD patients with edema. However, FM is overestimated in PD patients with edema. The difference between the two measurements increases as the grade of edema increases