Initiation of hypertension treatment in young adults in UK primary care: a retrospective cohort study using electronic health records
Problem
Eligibility for antihypertensive treatment is determined from blood pressure (BP) and predicted ten-year risk of cardiovascular disease (CVD). Currently, patients without pre-existing cardiovascular disease are eligible for BP treatment if their BP is ≥160/100 mm Hg or 140/90 to 159/99 and at ≥20% ten-year CVD risk. We investigated initiations of antihypertensive drugs in young adults aged 18-40 years to determine the proportion who were eligible for treatment.
Approach
A retrospective cohort study using an anonymised electronic primary care health record database.Setting Electronic health records using The Health Improvement Network (THIN). This included individual health records of approximately 4 million patients uploaded from general practices using Vision primary care records software.Participants Included patients were aged 18 to 40 years, registered in a THIN practice for at least one year between 1st January 2005 and 1st January 2018, free from cardiovascular disease and previously not treated with antihypertensives. A total of 19,006 patients were eligible for inclusion (initiated n=1357 vs. not-initiated on antihypertensive medication n=17649), with 142,238 person-years of follow-up. Main outcome measuresPatients were categorised into BP and ten-year CVD risk bands based on a rolling yearly average of their BP and calculated CVD risk (QRisk). Because average BP could change over time, each patient could have periods of exposure in more than one blood pressure category and ten-year CVD risk band. Initiation rates of antihypertensive medication were reported as patient years of follow-up and annual initiation rates. We also used a multivariable cox proportional hazards model to observe factors predicting initiation of antihypertensive medication reported as HR and CI.
Findings
Of 19,006 patients with 142,238 person-years of follow-up, 7.1% (1357) were prescribed antihypertensive medication: Of these 52.1% (707/1357) (95% CI 49.4% to 54.8%) of patients had a mean blood pressure <140/90 mm Hg and 32.0% (434/1357) (95% CI 29.5% to 34.6%) had blood pressure 140/90 to 159/99 mm Hg but were at <20% ten-year CVD risk and thus not eligible for treatment. Therefore, only 15.9% (216/1357) (95% CI 14.0% to 18.0%) were eligible for treatment who were initiated on antihypertensive medication. Under updated NICE guidelines (≥10% ten-year CVD risk) eligibility for treatment would rise to 21.8% (95% CI 19.7% to 24.2%). Furthermore, rates of antihypertensive drug initiation were lower in patients in lower blood pressure and lower ten-year CVD risk categories.
Consequences
The great majority of young adults initiated on antihypertensive treatment are not eligible (even when adjusting for updated guidelines of <10% ten-year CVD) resulting in further management, unnecessary treatment and cost to healthcare services. Novel strategies are needed to prevent overtreatment and stratify antihypertensive initiation in young adults.