COMPARATIVE EVALUATION OF HEMODIALYSIS ADEQUACY METRICS IN PEDIATRIC ESRD PATIENTS: SPKT/V VERSUS UREA REDUCTION RATIO (URR)

Abstract

Background: Assessment of hemodialysis adequacy is essential in pediatric end-stage renal disease (ESRD). Single-pool Kt/V (spKt/V) and urea reduction ratio (URR) are widely used measures, but their agreement and clinical utility in children may differ. Objective: To compare spKt/V and URR for assessment of hemodialysis adequacy in pediatric ESRD patients and identify factors associated with inadequate dialysis. Methods: This retrospective observational study was conducted at Pediatric Nephrology,  University of Child Health Sciences and The Children's Hospital, Lahore from January 2026 to June 2026, and included 170 pediatric patients with ESRD receiving maintenance hemodialysis. Demographic and clinical variables including age, gender, body weight, height, body mass index, underlying cause of ESRD, duration of dialysis, vascular access type, dialysis frequency, session duration, blood flow rate, dialysate flow rate, and ultrafiltration volume were recorded. Results: The mean age was 12.84±3.41 years, and 98 (57.6%) patients were male. Mean spKt/V was 1.43±0.24 and mean URR was 69.89±7.62%. Adequate dialysis was identified in 136 (80.0%) patients by spKt/V and 128 (75.3%) by URR. Both measures classified 124 (72.9%) patients as adequate and 30 (17.6%) as inadequate, while discordant classification occurred in 16 (9.4%) patients. URR and spKt/V showed a strong positive correlation (r=0.82, p<0.001) and substantial agreement (κ=0.73, p<0.001). URR demonstrated 91.2% sensitivity, 88.2% specificity, 96.9% positive predictive value, 71.4% negative predictive value, and 90.6% overall diagnostic accuracy using spKt/V as the reference. Conclusion: spKt/V and URR showed strong correlation and substantial agreement in pediatric ESRD patients, although a small proportion were classified differently. Shorter dialysis sessions, lower treatment frequency, catheter-based vascular access, and low blood flow were associated with inadequate dialysis.