Abstract FR559: Risks of hyperkalaemia with potassium-enriched salt substitute among patients using concomitant blockade of the renin-angiotensin-aldosterone system in the Salt Substitute and Stroke Study

Background: Potassium-enriched salt substitutes have been shown to reduce stroke, cardiovascular events, and all-cause mortality regardless of background use of antihypertensive drug therapy. However, concerns have been raised about the potential for causing hyperkalemia in patients with concomitant use of renin-angiotensin-aldosterone system (RAAS) blockers. Methods: This post hoc analysis of the Salt Substitute and Stroke Study evaluated hyperkalemia risk, among participant subgroups that were and were not using RAAS blockade. Effects were compared between these subgroups for those assigned to potassium-enriched salt (75% sodium chloride, 25% potassium chloride) versus regular salt by estimating rate ratios and testing for heterogeneity. Results: Among the 20,995 participants, 4,828 were using a RAAS blocker at baseline and 16,167 were not. There were 315 possible hyperkalemia events recorded during a median follow-up of 4.7 years. No overall increased risk was observed among those assigned to potassium-enriched salt substitute versus regular salt (rate ratio 1.04, 95% confidence interval 0.80 to 1.37). The rate ratio was 0.94 (0.57 to 1.55) for those with baseline use of RAAS blockade and 1.08 (0.80 to 1.45) for those not using RAAS blockade (p homogeneity=0.63). There were likewise no differences between these participant subgroups for risks of sudden death (1,133 events) or total mortality (4,172 events) (both p homogeneity>0.79). Conclusions: There was no evidence that potassium-enriched salt use increased the risk of hyperkalaemia, sudden death or total mortality in patients with concomitant use of RAAS blockade. The use of RAAS blockade should not be a contra-indication to using a potassium-enriched salt substitute. Clinical Trial Registration: ClinicalTrials.gov number NCT02092090 ( https://clinicaltrials.gov/study/NCT02092090 )