Prevalence and predictors of treatment for uncomplicated mild hypertension: a retrospective analysis of the Clinical Practice Research Datalink

Problem

There is little evidence to support initiation of pharmacological treatment in patients with uncomplicated (low risk) mild hypertension and that which exists remains inconclusive. Clinical guidelines make important recommendations based on ‘expert opinion’ and these are predictably contradictory, with those in the UK promoting lifestyle modification whilst others in Europe encourage prescription of drug therapy. This study aimed to establish the prevalence of lifestyle advice and pharmacological treatment for uncomplicated mild hypertension in Primary Care, and identify factors which predict prescription of therapy.

Approach

Data were extracted from the Clinical Practice Research Datalink from patients who were aged between 18-74 years, with no history of cardiovascular disease (CVD), diabetes or chronic kidney disease, three consecutive blood pressure readings between 140/90-159/99mmHg (within 12 months of each other) and no record of any previous blood pressure lowering treatment in the preceding 12 months. The prevalence of treatment in the 12 months after the third blood pressure reading was estimated by according to year, adjusted for age and sex. Segmented regression was used to examine how the introduction of the NHS health check affected prevalence rates. Logistic regression models were constructed to examine factors which predict the likelihood of treatment. Missing data for BMI were imputed.

Findings

A total of 108,935 patients from 694 practices fulfilled the eligibility criteria for the study (mean age 52.9±12.9 years, 60.0% female). Of these, 7,106 (6.5%) patients were given lifestyle advice, 16,582 (15.2%) patients were prescribed treatment and 2,561 (2.4%) patients were given lifestyle advice and treatment. From 1999 to 2009, treatment prescriptions were given to approximately 15.0% (95% CI 13.8%-16.2%) of patients and rates did not significantly change over time. However, following the introduction of the NHS health check in April 2009, the prevalence of treatment prescriptions decreased significantly by 1.2% per year (95% CI 1.7% - 0.8%). Patients with higher blood pressure (OR 1.03, 95%CI 1.02-1.04 [systolic]; OR 1.12, 95%CI 1.11-1.14 [diastolic]) and other preventative drug prescriptions (OR 3.89, 95%CI 3.01-5.02 [statins]; OR 7.79, 95%CI 5.73-10.59 [antiplatelets]) were more likely to receive antihypertensive treatment prescriptions.

Consequences

Treatment prescriptions are more commonly given to patients with uncomplicated mild hypertension than lifestyle advice, despite such an approach not being evidence based, nor recommended in clinical guidelines. The prevalence of treatment prescriptions has decreased in recent years since the introduction of the NHS health check, but GPs should still exercise caution when continuing to prescribe antihypertensive treatment in patients with higher blood pressure (in the mild hypertensive range) in the absence of robust evidence to support such an approach, particularly given that these medications may be prescribed for many years.