THE ASSOCIATION BETWEEN ANTIHYPERTENSIVE TREATMENT AND SERIOUS ADVERSE EVENTS BY PREVIOUS HISTORY OF ADVERSE EVENTS: AN OBSERVATIONAL COHORT STUDY

Abstract

Objective: Antihypertensives are effective at reducing the risk of cardiovascular disease, but are also associated with an increased risk of serious adverse events (SAEs), particularly in older people. Since these patients may also be at increased risk of cardiovascular disease, guidelines recommend deprescribing medications only in those with a previous history of adverse events. This study examined whether the association between antihypertensive treatment and adverse events is greater in this population. Design and method: This was an observational cohort study, using data from the Clinical Practice Research Datalink in England (Aurum and Gold databases combined). 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 primary care consultations for gout. The association between treatment and SAEs was examined by Cox regression, using propensity score adjustment, sub-grouped by whether or not individuals had a history of adverse events. 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. A total of 902,100 patients (23.5%) had a history of previous adverse events. Over 7.1 years, antihypertensives were associated with an increased risk of hypotension, syncope, falls, AKI, electrolyte abnormalities and gout but not fractures. For those with no history of adverse events, the absolute risk of SAEs with treatment small, ranging from 6 (falls) to 16 (AKI) events per 10,000 patients treated per year. However, in those with a previous history of these adverse events, the risk was notably higher, ranging from 19 (falls) to 80 (AKI) events per 10,000 patients treated per year. Conclusions: Antihypertensive treatment is associated with an increased risk of SAEs particularly in those with a history of serious adverse events. Clinical guidelines should continue to recommend that patients with a history of serious adverse events are recommended as candidates for deprescribing interventions.