Peritoneal and Urinary Sodium Removal in Refractory Congestive Heart Failure Patients Included in an Ambulatory Peritoneal Dialysis Program: Valuable for Monitoring the Course of the Disease

INTRODUCTION: Spot urinary sodium emerged as a useful parameter for assessing decongestion in patients with congestive heart failure (CHF). Growing evidence endorses the therapeutic role of continuous ambulatory peritoneal dialysis (CAPD) in patients with refractory CHF and kidney disease. We aimed to examine the long-term trajectory of urinary, peritoneal, and total (urinary plus peritoneal) sodium removal in a cohort of patients with refractory CHF enrolled in a CAPD program. Additionally, we explored whether sodium removal was associated with the risk of long-term mortality and episodes of worsening heart failure (WHF). METHODS: We included 66 ambulatory patients with refractory CHF enrolled in a CAPD program in a single teaching center. 24-h peritoneal, urinary, and total sodium elimination were analyzed at baseline and after CAPD initiation. Its trajectories over time were calculated using joint modeling of longitudinal and survival data. Within the framework of joint frailty models for recurrent and terminal events, we estimated its prognostic effect on recurrent episodes of WHF. RESULTS: At the time of enrollment, the mean age and estimated glomerular filtration rate were 72.8 ± 8.4 years and 28.5 ± 14.3 mL/min/1.73 m(2), respectively. The median urinary sodium at baseline was 2.34 g/day (1.40–3.55). At a median (p25%–p75%) follow-up of 2.93 (1.93–3.72) years, we registered 0.28 deaths and 0.24 episodes of WHF per 1 person-year. Compared to baseline (urinary), CAPD led to increased sodium excretion (urinary plus dialyzed) since the first follow-up visit (p < 0.001). Over the follow-up, repeated measurements of total sodium removal were associated with a lower risk of death and episodes of WHF. CONCLUSIONS: CAPD increased sodium removal in patients with refractory CHF. Elevated sodium removal identified those patients with a lower risk of death and episodes of WHF.