Scalable low-cost interventions to support medication adherence in people prescribed treatment for hypertension in primary care: a research programme

Background About 14.9% of people (9.9 million) registered with primary care practices in England and Wales are prescribed medication for hypertension. However, many do not take their medication as prescribed. To address this problem, we need scalable interventions. Objective To develop a scalable low-cost intervention to support medication adherence in people prescribed medication for hypertension in primary care, and to obtain precise and robust estimates of the effectiveness and cost-effectiveness of the intervention compared with usual care. Design Systematic reviews and meta-analyses; qualitative meta-synthesis; interviews and focus groups; expert consultations; pre-testing study; randomised feasibility trial; randomised controlled trial of effectiveness and cost-effectiveness; economic modelling. Setting and participants Primary care practices in England and Wales. Patients prescribed medication for hypertension with poorly controlled blood pressure. Interventions Very brief intervention delivered by a practice nurse or healthcare assistant followed by a digital intervention (text messaging programme or smartphone app). Main outcome measures Acceptability, feasibility, fidelity and cost of the interventions. Systolic blood pressure. Biochemical and self-reported measures of medication adherence. Results Our systematic reviews showed that both app-based and face-to-face interventions in patients with long-term conditions have a positive effect on medication adherence. The meta-synthesis of published qualitative studies showed that: digital interventions to support medication use were perceived as acceptable and useful; a digital intervention would be more effective if it was personalised and tailored; barriers to using digital interventions included lack of interest, lack of confidence and lack of proficiency and experience in using the technology; digital interventions should be simple, easy to navigate and age-appropriate; patients wanted accurate information on their health condition, potential side effects of medication and health consequences of non-adherence; reminder notifications and a self-monitoring feature were perceived as helpful by some patients; some patients suggested that a digital intervention should enable them to communicate with pharmacies, but practitioners were concerned that this would increase their workload. The interview and focus group study identified several barriers to adherence, including forgetting, unpleasant side effects and reluctance to medicate. A digital intervention to support medication adherence was acceptable to patients if it was user-friendly, the content was tailored to the user, and the privacy of user data was protected. Simple reminder messages for taking medication and reordering prescriptions were considered more useful by patients than those providing information on the benefits of medication or the consequences of non-adherence. Patients preferred to receive feedback on their adherence levels in the form of a simple graph, percentage score or statistic. Practitioners thought that it would be feasible to introduce a digital intervention to patients in a very brief face-to-face consultation. In the pre-testing study, participants reported that the interventions we developed were easy to use and that they would recommend them to others. The feasibility trial showed that the combined intervention was acceptable and that a large cost-effectiveness trial was feasible. The main trial showed no difference between arms in systolic blood pressure or medication adherence at 12-month follow-up. The estimate (95% confidence interval) for the difference in means between arms in self-measured systolic blood pressure at 12 months was −0.61 mmHg (−3.05 to 1.82), p = 0.62 [for intervention vs. control (reference group)]. In the base case analysis, the intervention had a mean incremental cost-effectiveness ratio below the usual willingness-to-pay thresholds in the National Health Service in the United Kingdom. The probability of cost-effectiveness was between 77% and 80% at willingness-to-pay thresholds of £15,000, £20,000 and £30,000 per quality-adjusted life-year, but the confidence intervals are wide and cross zero, indicating some chance that the intervention could be less effective and more costly. Limitations The effectiveness trial was conducted during the COVID-19 pandemic. To reduce the risk of infection, the very brief intervention was delivered by telephone instead of face-to-face, and all study measurements were conducted remotely. This may have led to lower response rates and data quality and lower effectiveness of the intervention. A significant proportion (24%) of participants did not have raised blood pressure at baseline, and self-reported medication adherence was high at baseline, which reduced the possible scope for an intervention effect. Conclusions The findings on effectiveness do not support the commissioning of the intervention in United Kingdom primary care. The cost-effectiveness findings are more equivocal, showing a high probability of being cost-effective at standard United Kingdom willingness-to-pay thresholds, but with some uncertainty. Future work Future research should address the challenge of identifying and recruiting people who are poorly adherent and have raised blood pressure and test the intervention in this group. Variants such as face-to-face delivery, adding a follow-up consultation or a purely digital version could also be investigated. Study registration This study is registered as CRD42017080150; CRD42020164049; ISRCTN12805654; ISRCTN74504989; ISRCTN82013652. Funding This award was funded by the National Institute for Health and Care Research (NIHR) Programme Grants for Applied Research Programme (NIHR award ref: RP-PG-0615-20013) and is published in full in Programme Grants for Applied Research ; Vol. 14, No. 18. See the NIHR Funding and Awards website for further award information.