Overhydration prevalence in peritoneal dialysis – A 2 year longitudinal analysis

Background and objectives: Hypervolemia is a major concern in dialysis patients, and is associated with increased cardiovascular risk and death. Cross sectional analysis have previously demonstrated that peritoneal dialysis (PD) patients are not more overhydrated when compared to haemodialysiś ones. This study was designed to evaluate longitudinal trends in hydration status and corporal composition in a PD population. Methods: We conducted a 2 year prospective observational study of 58 PD patients from a single centre. Incident and prevalent patients were included. Yearly measurements were performed using multifrequency electric bioimpedance. Overhydration (OH) was defined as an extra-cellular water (ECW)/total body water (TBW) over 15%. Clinical and biochemical variables were also explored. Results: A total of 30 patients completed evaluation (female 63.3%, mean age 56.9 years, BMI 25.0 kg/m2, diabetes 10.0%, APD-50.0%). Median PD vintage was 21.9 months, and 36.7% were anuric. At baseline 6.7% were overhydrated. On longitudinal analysis no significant changes were found in hydration status, systolic blood pressure, pro-BNP, nor albumin levels. Similar results were found among incident (n=11; APD- 45.5%; anuric- 9.1%) and prevalent (n=19; APD- 52.6%; anuric- 52.6%) patients (p>.05). However, at the second year, prevalent patients were moderately overhydrated compared to incident ones (median 10.2% vs 3.5%; p=.009). Nonetheless, no statistical difference was observed considering adequacy, TBW, or ECW. Moreover, nutritional parameters remained stable. Conclusions: Peritoneal dialysis maintenance without increasing volume status, nor major deleterious corporal composition trends, is feasible under careful therapy strategies. Longitudinal application of BIA may be a useful clinical tool to evaluate adequacy beyond Kt/V.