LAUSR

Objective: Antihypertensives are effective at reducing the risk of cardiovascular disease, but limited data exist quantifying their association with serious adverse events (SAEs), particularly in older people with frailty. This study examined this association using data from a large database of electronic health records. Design and method: This was a retrospective observational cohort study, utilising data from the Clinical Practice Research Datalink in England. Patients were eligible if they were aged 40 years or older, with a systolic blood pressure reading between 130–179 mmHg and not previously prescribed antihypertensive treatment. Outcomes were defined as hospitalisation or death within 10 years due to hypotension, syncope, falls, fractures, acute kidney injury (AKI), electrolyte abnormalities and gout. The association between antihypertensive treatment and SAEs was examined by cox regression, using propensity score adjustment to adjust for confounding. Subgroup analyses were undertaken by age and frailty. Results: A total of 3,834,056 patients, aged 57 ± 12 years, were eligible for the study. Of these, 484,187 (12.6%) were prescribed antihypertensive medication in the 12 months prior to the index date. Over a median follow-up of 7.1 years, antihypertensives were associated with an increased risk of hypotension (HR 1.32, 95%CI 1.29–1.35), syncope (HR 1.20, 95%CI 1.17–1.22), falls (HR 1.23, 95%CI 1.21–1.26), AKI (HR 1.44, 95%CI 1.41–1.47), electrolyte abnormalities (HR 1.42, 95%CI 1.43–1.48) and gout (HR 1.32, 95%CI 1.46–1.52). The absolute risk of SAEs with treatment was very low, ranging from four syncope events to twelve AKI events per 10,000 patients treated per year. In older patients and those with severe frailty, this risk was increased up to 116–120 events per 10,000 patients treated per year. Conclusions: Antihypertensive treatment is associated with an increased risk of SAEs, but the absolute risk of harm is very low. However, in older patients and those with severe frailty, this absolute risk is increased and physicians should take this risk into consideration when making prescribing decisions.