Risk of Acute Infections in New Users of Antihypertensive Drugs An Observational Cohort Study summary

This PACULit episode reviews a large observational cohort study by Aebi et al. using UK CPRD data (2000–2021) to compare new monotherapy users of amlodipine, ramipril, and bendroflūmethylthiazide (bendroflumethiazide) and to assess risk of acute outpatient infections (respiratory, genitourinary, gastrointestinal, sepsis) and SARS-CoV-2 infection during 2020–2021. The primary comparisons were amlodipine versus ramipril and amlodipine versus bendroflumethiazide, with follow-up from prescription start to infection, censoring, or study end. Propensity score weighting balanced baseline covariates, and the study excluded individuals with prior cardiovascular disease to reduce confounding. Findings showed lower infection incidence among amlodipine users (IRR 0.77 vs ramipril; 0.78 vs bendroflumethiazide; infections per 1,000 person-years: 38.9 vs 51.6). During the COVID-19 period, amlodipine was associated with a 43% reduced risk of diagnosed SARS-CoV-2 infection (IRR 0.57). The discussion notes potential immunomodulatory and anti-inflammatory mechanisms, cites in vitro and endothelial studies, and acknowledges limitations inherent to observational designs (residual confounding, potential misclassification, and lack of randomized causality). Implications suggest considering possible infection-related benefits when initiating antihypertensive therapy, while emphasizing the need for randomized trials to confirm causality and assess broader outcomes.