Urgent Start of Peritoneal Dialysis Versus Hemodialysis in Kidney Failure in Severe Metabolic Acidosis: A Prospective Study.

BACKGROUND: Severe metabolic acidosis is a life-threatening complication of kidney failure and a common indication for urgent KRT. Although hemodialysis (HD) is traditionally considered the preferred modality for rapid acid-base correction, comparative evidence with urgent-start peritoneal dialysis (PD) remains limited. METHODS: We conducted a prospective cohort study including 68 consecutive dialysis-naïve patients with kidney failure and severe metabolic acidosis requiring urgent KRT at a tertiary referral center (HD n=31; PD n=37). Modality selection was based on nephrologist clinical judgment and resource availability. The primary outcome was the trajectory of pH and serum bicarbonate from admission to 48 hours and discharge, analyzed using mixed-effects regression models with inverse probability of treatment weighting (IPTW). Secondary outcomes included in-hospital mortality and technique survival. RESULTS: Both modalities associated with improvement in acid-base parameters over time (p<0.001). Baseline bicarbonate levels were 7.6 mEq/L in HD and 12.1 mEq/L in PD (p=0.18), increasing to 16.6 and 18.2 mEq/L at discharge, respectively. No significant interaction between modality and time was observed for pH or bicarbonate trajectories in unadjusted or IPTW-adjusted analyses (interaction p>0.05). The magnitude of bicarbonate change was comparable between groups (Δ +9.0 vs. +6.1 mEq/L, p=0.12). In-hospital mortality (39% vs. 42%) and technique survival were also similar. CONCLUSIONS: In patients with kidney failure and severe metabolic acidosis requiring urgent KRT, urgent-start PD was associated with similar trajectories of acid-base correction and similar short-term clinical outcomes compared with HD, supporting PD as a safe and metabolically effective alternative in this setting.