# Impact of RAAS blockers on serum potassium and mortality in a large dialysis cohort: a longitudinal analysis

## TL;DR

This study examines how RAAS blockers affect potassium levels and survival in dialysis patients, finding a link to higher potassium but no impact on mortality.

## Contribution

The study provides new insights into RAAS blocker use in dialysis patients, challenging prior guidelines with real-world data.

## Key findings

- RAASIs were associated with increased serum potassium levels in dialysis patients.
- No significant association was found between RAASI use and mortality in dialysis patients.
- Stratified analysis showed no differences in mortality impact based on potassium levels.

## Abstract

Renin–angiotensin–aldosterone system inhibitors (RAASIs) are widely used antihypertensive drugs. Due to the hyperkalaemic effect, previous 2012 Kidney Disease: Improving Global Outcomes (KDIGO) guidelines discouraged RAASI use in patients with severe chronic kidney disease (CKD). However, due to the recently discovered cardioprotective and nephroprotective effects, the 2022 KDIGO guidelines suggest their use in CKD stage 4–5. To our knowledge, few studies have explored the use of RAASIs in dialysis patients. This study aims to evaluate the impact of RAASIs on kalaemia and on mortality in a large sample of dialysis patients.

We included 4764 dialysis patients from the Sicilian Registry of Nephrology, Dialysis and Transplantation. The longitudinal association between RAASI intake and serum potassium was analysed by univariate and multivariate linear mixed models. The survival models were computed through univariate and multivariate Cox models and Cox models with mixed effects.

The study included 4764 patients, of whom 1207 (25%) were treated with RAASis. Multivariate longitudinal models showed a direct association between RAASI intake and serum potassium {adjusted β = 0.10 [95% confidence interval (CI) 0.05–0.15], P < .001}. However, multivariate Cox analysis did not show any association between RAASI intake and mortality [adjusted hazard ratio 0.76 (95% CI 0.43–1.30), P = .31]. No differences in the impact of RAASIs on mortality were found in the analysis stratified for potassium levels (cut-off 5.1 mmol/l).

In the present study we found, in a large cohort of dialysis patients, an independent, direct association between RAASIs and serum potassium. However, no association was found between RAASI intake and mortality. Although specific randomized controlled trials are needed to confirm our findings, RAASI intake did not seem to have a negative impact on patients’ survival, thus suggesting a re-evaluation of RAASI use in this population.