Pharmacist interventions in the control of hypertension and adherence to anti-hypertensive treatment: A systematic review and meta-analysis of randomised controlled trials
Authors: McNally R J , Teo V , Imran H , Wright A , Waters B , Faconti L , Patel J , Stevenson J , Chowienczyk P J , Weinman J 
Published: November 2024

Abstract

Introduction
Non-adherence to antihypertensive therapy is one of the major barriers for the achievement of blood pressure (BP) control and has a significant cost burden1. Non-adherence is also thought to be one of the leading factors leading to ethnic disparities in hypertension control in the UK2. Pharmacists have an important role in the management of hypertension and non-adherence due to their ideal position to promote optimal use of medication3. Many have advocated for pharmacist involvement in team-based hypertension management, however which pharmaceutical care interventions are most effective remains unclear. There have been many new studies in recent years exploring the effect of pharmacist interventions in hypertension and this meta-analysis provides an update of the current literature and quantification of the results.

Aim
This study aimed to systematically evaluate the efficacy of pharmacist-delivered interventions for adults with hypertension and examine the intervention characteristics associated with greater BP-lowering efficacy. The primary outcome was the change in BP and secondary outcomes were % achieving BP control.

Methods
Systematic review and meta-analysis of randomized controlled trials (RCTs). This review was registered on PROSPERO. Embase, CENTRAL, MedLine, Psychinfo and CINAHL were searched until February 2024. Eligible studies included adult patients with a diagnosis of essential hypertension where a pharmacist intervention (alone or collaborative care) targeting BP control was compared with control (usual care). Exclusion criteria included secondary hypertension, pregnancy, children and review articles/case studies. The risk of bias was assessed by the Cochrane risk-of-bias tool for RCTs. The primary outcome was change in BP. We extracted data on sample and intervention characteristics. Meta-analysis was performed using Comprehensive Meta-Analysis Software v4. Moderator analyses examined the association between intervention effects and intervention features. This study was a systematic review and meta-analysis of already completed trials and so ethical approval was not required.

Results
2402 articles were retrieved. After removal of duplicates, 1538 were screened by title and abstract against the inclusion criteria. 88 studies with 25,516 participants were included. Mean intervention duration was 7.2 months (range 1-14 months). The overall pooled mean differences in systolic BP (SBP) and diastolic BP (DBP) between pharmacist intervention and control were -7.39 (-8.56, -6.23) mmHg and -3.99 (-4.61, -3.37) mmHg respectively, both P&lt;0.001. With BP control, pharmacist interventions caused a significant increase in those achieving BP control compared to usual care (+21 (16.88, 25.27) %, P&lt;0.001). Duration of intervention had no influence on change in SBP or DBP (both P&gt;0.05).

Discussion
Pharmacists can make a significant impact in the management of hypertension in respect to increasing treatment adherence and improving BP control and this study highlights the importance of including them as part of the multidisciplinary team responsible for patient care. Limitations of the present study include the inability to extract individual patient data and stratification by ethnicity, socioeconomic status and gender. However, pharmacist interventions in hypertension significantly reduced SBP and DBP and improved BP control. Identifying the characteristics of the most effective interventions can lead to better treatment adherence and BP-lowering in patients with hypertension.

References
1. Hamrahian SM, Maarouf OH, Fülöp T. A Critical Review of Medication Adherence in Hypertension: Barriers and Facilitators Clinicians Should Consider. Patient Prefer Adherence. 2022;16:2749-2757.
2. Eastwood SV, Hughes AD, Tomlinson L, Mathur R, Smeeth L, Bhaskaran K, Chaturvedi N. Ethnic differences in hypertension management, medication use and blood pressure control in UK primary care, 2006-2019: a retrospective cohort study. Lancet Reg Health Eur. 2022 Dec 5;25:100557.
3. Di Palo KE, Kish T. The role of the pharmacist in hypertension management. Curr Opin Cardiol. 2018 Jul;33(4):382-387.