Risk of developing hyperkalemia in patients with hypertension treated with combination antihypertensive therapy – a retrospective register-based study

The risk of hyperkalemia in relation to different combinations of antihypertensive therapy remains to be elucidated. In this Danish register-based study, we aimed to investigate the risk of developing hyperkalemia in relation to different combinations of antihypertensive therapy. Using incidence density matching, we matched a hyperkalemic patient to five normokalemic patients on eGFR groups, age, sex, and time between study entry and date of potassium measurement. Combination therapies were subdivided into eight groups: beta blockers (BB) + calcium channel blockers (CCB), BB + renin angiotensin system inhibitors (RASi), BB + RASi + mineralocorticoid receptor antagonists (MRA), CCB + RASi, CCB + RASi + thiazides, CCB + thiazides, RASi + thiazides, and other combinations. Multivariable conditional logistic regression was used to estimate the odds of hyperkalemia within 90 days for each of the eight antihypertensive combination therapies. A total of 793 patients with hyperkalemia were matched to 3598 normokalemic patients. In multivariable analysis, odds of developing hyperkalemia when being treated with BB + RASi + MRA was 1.95 (95% CI, 1.39–2.72) compared to RASi + thiazides (reference). CCB + thiazides (OR, 0.76 [95% CI, 0.45–1.28]) and CCB + RASi + Thiazid (OR 0.81 [95% CI, 0.51–1.28]) were among the others not significantly associated with hyperkalemia. Combinations of BB + RASi + MRA were significantly associated with an increased risk of developing hyperkalemia within 90 days of initiating treatment.