The Impact of Serum Potassium-Influencing Antihypertensive Drugs on the Risk of Out-of-Hospital Cardiac Arrest: A Case Control Study

BACKGROUND: Sudden cardiac arrest (SCA) is a complex multifactorial event and most commonly caused by ventricular tachycardia/ fibrillation (VT/ VF). Some antihypertensive drugs could induce hypokalaemia or hyperkalaemia that may increase susceptibility to VT/VF and SCA.

OBJECTIVE: To assess the association between different classes of antihypertensive drugs classified according to their potential impact on serum potassium levels and the occurrence of out-of-hospital cardiac arrest (OHCA) based on VT/VF.

METHODS: A case-control study was performed among current users of antihypertensive drugs. Cases were OHCA victims with electrocardiogram documented VT/VF drawn from the AmsteRdam REsuscitation STudies (ARREST) registry, and controls were non-OHCA individuals from the PHARMO database. Antihypertensive drugs were classified into: (1) antihypertensives with neutral effect on serum potassium levels; (2) hypokalaemia-inducing antihypertensives; (3) hyperkalaemia-inducing antihypertensives; (4) combination of antihypertensives with hypo- and hyperkalaemic effects.

RESULTS: We included 1,345 cases and 4,145 controls. The risk of OHCA was significantly increased among users of hypokalaemia-inducing antihypertensives (adjusted OR 1.39; 95%CI [1.10-1.76]) and among users of a combination of antihypertensives with hypo- and hyperkalaemic effects (adjusted OR 1.42; 95%CI [1.17-1.72]) versus users of antihypertensives with neutral effect. There was no difference in OHCA risk between users of hyperkalaemia-inducing antihypertensives versus users of antihypertensive drugs with neutral effect (adjusted OR 1.15; 95%CI [0.95-1.40]).

CONCLUSION: The risk of OHCA is significantly increased in patients who were current users of hypokalaemia-inducing antihypertensives and patients using a combination of antihypertensives with hypo- and hyperkalaemic effects.