Benefits and harms of treatment for patients with low risk mild hypertension

What we did

Hypertension is typically defined as a sustained clinic blood pressure at or above 140/90 mm Hg and clinical guidelines recommend treatment with lifestyle or drug interventions, depending on the underlying risk of heart attack and stroke (high risk patients which higher blood pressure should be given drug treatment sooner). Evidence to support initiation of drug treatment in patients with low-risk ‘mild’ hypertension (systolic blood pressure between 140-159 mm Hg) is inconclusive, with previous trials underpowered to demonstrate benefit. As a result clinical guidelines across the world are contradictory.

In this observational cohort study, we examined the electronic health records of 38,286 low risk patients with mild hypertension to determine the association between blood pressure lowering treatment and death, heart attack, stroke and adverse events. Over a median follow-up of 5.8 years, no evidence of an association was found between blood pressure lowering treatment and time to death or first heart attack or stroke. However, there was evidence that treatment may be associated with an increased risk of adverse events such as low blood pressure, fainting, electrolyte abnormalities (chemical imbalances in the body leading to symptoms such as muscle pain and nausea) and sudden kidney problems.

Although this work provides evidence from the largest cohort of patients with low risk mild hypertension ever studied, the methodology used could have led to bias with sicker patients ending up in the blood pressure lowering treatment group. There was no evidence of this, but if it had occurred, this could have led to a reduction in the observed benefits of treatment and exaggerated harms.

Where can I read more?

The results of this study were published in JAMA Internal Medicine. Further work examined the extent to which patients with low risk mild hypertension receive lifestyle advice and treatment, and how this has been affected by guideline and policy changes over the past 15 years. This analysis revealed approximately one third of patients received lifestyle advice whilst half were prescribed antihypertensive treatment. Changes in healthcare policy were associated with an increase in the proportion of patients being offered lifestyle advice, but had no impact on the proportion being offered drug treatment. This work was published in BMJ Open and can be found here.