Rates of delirium associated with calcium channel blockers compared to diuretics, renin-angiotensin system agents and beta-blockers: An electronic health records network study.

Background: Antihypertensive drugs, especially calcium channel blockers, have been associated with differential rates of a number of neuropsychiatric outcomes. Delirium is commonly attributed to medication, including antihypertensive drugs, but delirium incidence has not been compared directly between antihypertensive drug classes. Methods: Using a federated electronic health records network of 25.5 million people aged 50 years or older, we measured rates of delirium over a two-year period in patients prescribed calcium channel blockers compared to the other main antihypertensive drug classes. Extensive propensity score matching was used to create cohorts matched for a range of demographic factors and delirium risk factors. Negative control outcomes were also measured. Results: Cohort sizes ranged from 54,000-577,000. Delirium was more common with calcium channel blockers than with renin-angiotensin system agents (similar to 40% higher) but less common than with beta-blockers (similar to 20% lower). These differences remained when patients with a range of other delirium risk factors were excluded, and they were not paralleled by the negative control outcomes. Comparisons between calcium channel blockers and diuretics produced inconclusive results. Conclusions: Calcium channel blockers are associated with higher rates of delirium than renin-angiotensin system agents, but tower rates compared to beta-blockers. The findings add to the list of factors which may be considered when choosing antihypertensive drug class.