Peritoneal thickness and its correlation with dialysis adequacy in peritoneal dialysis patients

To investigate the association between computed tomography (CT)-measured parietal peritoneal thickness and clinically relevant indices of dialysis adequacy, and to explore its potential role as a non-invasive imaging biomarker of peritoneal structural remodeling in patients undergoing maintenance peritoneal dialysis. This cross-sectional study included 87 patients undergoing continuous ambulatory peritoneal dialysis (CAPD). Dialysis adequacy was defined according to the Kidney Disease Outcomes Quality Initiative (KDOQI) criteria (total Kt/V ≥ 1.7 and total creatinine clearance ≥ 50 L/week/1.73 m²). CT-measured parietal peritoneal thickness was obtained as the mean of four standardized abdominal measurement sites for each patient. Patients were further stratified into high- and low-thickness groups using the cohort median of the individual mean peritoneal thickness (0.79 mm) as the cutoff. Clinical characteristics, peritoneal transport parameters, and laboratory findings were compared between groups. Correlation analyses and multivariable regression models were performed to identify factors independently associated with peritoneal thickness and dialysis inadequacy. Patients with dialysis inadequacy had significantly greater CT-measured peritoneal thickness than those with adequate dialysis. Greater peritoneal thickness was independently associated with an increased likelihood of dialysis inadequacy (OR = 2.561, P = 0.018). It was negatively correlated with serum albumin level, daily ultrafiltration volume, and angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) use use, and positively correlated with dialysate-to-plasma creatinine ratio (4-h D/P Cr), peritoneal creatinine clearance, dialysis vintage, number of peritonitis episodes, use of 2.5% glucose dialysate, and blood glucose level (all P < 0.05). Multivariable linear regression identified dialysis vintage as an independent determinant of increased peritoneal thickness (β = 0.356, P < 0.01). CT-measured parietal peritoneal thickness was independently associated with dialysis inadequacy in patients undergoing CAPD. Longer dialysis vintage, more frequent peritonitis episodes, and greater exposure to hypertonic glucose dialysate were associated with increased peritoneal thickness, whereas ACEI/ARB therapy showed a protective association. CT-measured peritoneal thickness may serve as a complementary non-invasive imaging biomarker of peritoneal structural remodeling that complements, rather than replaces, conventional assessments of dialysis adequacy.