A multifaceted pharmacist intervention to improve antihypertensive adherence: a cluster-randomized, controlled trial (HAPPy trial)

What is known and objectives: About half of all patients taking antihypertensives discontinue treatment by 12 months. There is potential for substantial health gains at both individual and population levels through improved treatment adherence. The objective was to evaluate a community pharmacist intervention to improve adherence with antihypertensive medicines with a view to improving blood pressure (BP) control.

Methods:

Design: prospective, non-blinded, cluster-randomized, controlled trial.

Participants: adults with primary hypertension who obtained antihypertensives in the previous 6 months. Patients with poor refill adherence were preferentially identified with the help of a purpose-built software application.

Intervention: package comprising BP monitor; training on BP self-monitoring; motivational interviewing; medication use review; prescription refill reminders.

Follow-up: six months.

Primary outcome: change in proportion self-reporting medication adherence.

Secondary outcome: BP changes.

Results: Participants (n = 395; intervention – 207; control – 188) had a mean age of 66.7 years; 51.1% were males. The proportion of adherent participants increased in both groups but was not significantly different between groups [57·2% to 63·6% (control) vs. 60·0% to 73·5% (intervention), P = 0·23]. The mean reduction in systolic BP was significantly greater in the intervention group (10·0 mmHg vs. 4·6 mmHg; P = 0·05). The proportion of patients who were non-adherent at baseline and adherent at 6 months was 22·6% (95%CI 5·1–40·0%) higher in the intervention group (61·8% vs. 39·2%, P = 0·007). Among participants with baseline BP above target, reduction of systolic BP was significantly greater in the intervention group [by 7·2 mmHg (95%CI 1·6–12·8 mmHg); (P = 0·01)]. Among participants non-adherent at baseline and above target BP, the proportion reporting adherence at 6 months was significantly greater in the intervention group [56·8% vs. 35·9%, P = 0·039).

What is new and conclusion: This community pharmacist intervention resulted in improved adherence to antihypertensive medication and reduced systolic BP.