Determinants of thirst in peritoneal dialysis patients

Background Fluid 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. Methods We 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). Results Higher 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. Conclusion While 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.