Determinants of thirst in peritoneal dialysis patients

BackgroundFluid overload adversely impacts on peritoneal dialysis (PD) patients, and fluid restriction is often advised. Thirst is a prevalent and distressing symptom in patients with end-stage kidney disease. Thirst determinants in PD patients are poorly understood, so we wished to evaluate thirst and its determinants in this population.MethodsWe report a cross-sectional study of 387 adult PD patients attending a dialysis centre in London from January 2020 to December 2023. Patients completed a visual analogue scale for thirst, and clinical, biochemical and multifrequency bioelectrical bioimpedance data were reviewed. Based on thirst intensity scores, patients were categorized into three groups: 121 patients (0-3; low thirst), 136 (5-6; moderate thirst) and 130 (6-10; high thirst).ResultsHigher thirst scores were associated with female gender (p = 0.03); lower median of total weekly urea clearance (1.92 vs 1.97 and 2.09, lower and moderate thirst groups respectively; p = 0.04); and higher daily net sodium removal (136 vs 123 and 115 mmoL, lower and moderate thirst groups respectively; p = 0.009). On bivariate analysis, body mass index (BMI) showed a weak inverse correlation with thirst score (p = 0.046). However, there was no association with measured serum osmolality.ConclusionWhile there were weak to moderate associations between thirst and female gender, BMI, higher daily net sodium removal and lower weekly total Kt/V, there was a lack of a robust association with any routinely collected clinical measure. This study highlights the complex mechanism and determinants of thirst in PD patients warranting further study.