Serum beta2 microglobulin (beta2MG) level is a potential predictor for encapsulating peritoneal sclerosis (EPS) in peritoneal dialysis patients.

Background: Encapsulating peritoneal sclerosis (EPS) is a serious complication in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) or automated peritoneal dialysis (APD). The aim of this study was to find a predictor for EPS. Methods: Patients with EPS who were detected by a historical cohort study using clinical data of 219 CAPD patients at our hospital. We recruited 25 patients with EPS who were compared with the patients without EPS who were matched for age and dialysis period as controls. Differences between the two groups (non-EPS group and EPS group) with respect to age, gender, primary disease, dialysis period, serum urea nitrogen, serum creatinine, β 2 MG, CRP and PET (peritoneal equilibration test) category (determined by the peritoneal function testing) were analyzed. Results: According to multiple regression analysis, a high β 2 MG level was an independent risk factor for EPS (odds ratio 1.162, 95% confidence interval 1.026 - 1.317, p = 0.018). Other clinical markers did not show positive significance. A ROC (receiver operating characteristic) curve was prepared to evaluate the suitability of β 2 MG measurement as a screening test. The sensitivity was 64% and the specificity was 80% when a β 2 MG level of 37.0 mg/dl was taken as the cut-off value. The odds ratio for occurrence of EPS was 8.8 when β 2 MG level was in the range of 35 - 40 mg/dl, 13.5 when β 2 MG level was > 40 mg/dl and 1 when β 2 MG level was < 30 mg/dl. Conclusion: These findings suggest that β 2 MG is useful as a screening test for the onset of EPS, and that β 2 MG and accumulation of middle-molecular uremic substances may be related to the pathophysiology of EPS.