4C-04 - Trends in first-line monotherapy and combination therapy for hypertension in UK primary care

Background: Debate remains about the optimal first-line treatment strategy for hypertension. Most international guidelines recommend first-line combination therapy for most patients, following evidence that it leads to better blood pressure control. However, in the United Kingdom (UK), first-line monotherapy is still the recommended approach.

Objectives: To assess trends in the use of first-line antihypertensive monotherapy and combination therapy in UK primary care between 2011 and 2019.

Methods: Using the UK’s Clinical Practice Research Datalink, we formed a cohort of all patients with an incident hypertension diagnosis between January 1, 2011, and December 31, 2019. We calculated the proportion of patients newly prescribed first-line monotherapy and combination therapy within 3 months of diagnosis overall and in each calendar year. We also described changes over time in patient characteristics associated with each type of therapy. Finally, we used Kaplan-Meier methods to estimate the median treatment persistence, and the probability of persistence at 6 months and one year for mono- and combination therapy.

Results: Among 535,234 patients diagnosed with hypertension, 92.6% initiated antihypertensive treatment within three months of diagnosis. Of these, 15,962 (3.2%) were prescribed combination therapy. There was little change in the proportion of patients receiving combination therapy across the study period. Rates of combination therapy initiation were 21% (95% CI 17%-25%) higher in women than men, 42% (95% CI 36%-38%) higher in patients with stage 3 compared to stage 1 hypertension, and showed significant variation by UK nation and age. Patients prescribed combination therapy were more likely to have severe hypertension and cardiovascular comorbidities, although the proportion of patients with a prior myocardial infarction or coronary heart disease fell over time. The median treatment persistence was 80 (95% CI 77-84) days for combination therapy initiators, compared to 184 (95% CI 183-185) days for patients on monotherapy. At 6 months, 30% (95% CI 29.4%-30.7%) of combination therapy and 50.2% (95% CI 50%-50.3%) of monotherapy initiators remained on first-line treatment; at one year the numbers fell to 21.2% (95% CI 20.6%-21.8%) and 36.7% (95% CI 36.6%-36.9%), respectively.

Conclusions: First-line combination therapy remains rare in the UK despite growing consensus that it may be more beneficial than monotherapy. Distinct characteristics and short treatment persistence suggests selective prescribing of combination therapy to patients with worse cardiovascular profile.