Systematic review will map non-drug blood pressure strategies in prehypertension
Prehypertension sits in the clinical space between normal blood pressure and established hypertension, and that position carries real consequence. People in this range are already on a trajectory toward future hypertension, with downstream risk for cardiovascular disease, myocardial infarction, and stroke. In the UK, non-pharmacological approaches are recommended for management, yet evidence has been scattered across broader blood pressure populations rather than focused specifically on people with prehypertension.
This protocol sets out a systematic review designed to answer a narrower question: which non-pharmacological interventions reduce blood pressure, maintain blood pressure, or do both in adults with prehypertension, and whether those strategies are cost-effective. The focus matters because treatment decisions at this stage often aim to delay progression rather than reverse advanced vascular disease. Interventions that improve diet, physical activity, weight control, or other behavioural pathways may alter sympathetic tone, vascular resistance, endothelial function, and long-term cardiometabolic risk before antihypertensive drugs become necessary.
The review is registered in PROSPERO and will be conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance. It will bring together evidence from randomised controlled trials and economic evaluations, then assess how consistent and usable that evidence is for practice and policy.
Broad database searching is intended to capture both efficacy and economic evidence
Investigators plan to search Medline, EMBASE, CINAHL, PsycINFO, CENTRAL, the WHO International Clinical Trials Registry Platform, ClinicalTrials.gov, the Cochrane Library, Scopus, and the International HTA Database. An information specialist helped develop the search terms, which is important in a field where useful studies can be indexed under lifestyle, prevention, cardiovascular risk reduction, or health promotion rather than prehypertension alone. By spanning bibliographic databases, trial registries, and health technology assessment sources, the search strategy is built to capture both published and ongoing work.
Three reviewers will take part in study selection. That matters because intervention reviews in behavioural medicine often depend on consistent screening of heterogeneous studies, especially when trials vary in setting, intervention intensity, follow-up length, and the blood pressure thresholds used to define prehypertension. A tri-reviewer process reduces the chance that relevant evidence is missed during title, abstract, or full-text review.
The protocol also makes room for economic evaluations, which is where many lifestyle interventions either gain or lose their appeal. A program can lower blood pressure yet still be difficult to implement at scale if staffing, adherence support, or delivery costs are too high. Health systems need both clinical effect and value for money when deciding whether to embed such interventions in routine care.
Heterogeneity is likely to be the central interpretive challenge
The review will evaluate risk of bias in randomized trials using the Cochrane risk-of-bias tool, while economic studies will be appraised with the Consensus Health Economic Criteria list. Those tools are well suited to this question because non-drug interventions are especially vulnerable to problems in allocation concealment, blinding, attrition, and outcome measurement. In lifestyle research, participants and providers usually know which intervention is being delivered, so the key issue becomes how well the trial controls for expectation effects, co-interventions, and missing data.
Findings will be tabulated and synthesized narratively. Forest plots, where available, will be inspected visually, and heterogeneity will be quantified with the χ2 test and I2 statistic. If enough data are available, the team plans meta-regression to explore why effects differ across studies, including differences between intervention types and possible subgroup variation. This is a sensible design choice because the term “non-pharmacological intervention” can include a wide range of approaches, from structured exercise and dietary change to multicomponent programmes, and those strategies do not work through identical biological or behavioural pathways.
A brief result from a single trial can look encouraging, but the real question is whether the effect persists across settings and populations. In prehypertension, small shifts in systolic or diastolic pressure may still have practical meaning because the target population has not yet crossed into established hypertension, where the treatment burden is usually heavier and the vascular burden is often more fixed.
Blood pressure maintenance may matter as much as reduction
The protocol does not restrict its interest to blood pressure lowering alone. It also includes maintenance of blood pressure, which is clinically relevant in prehypertension because a stable reading below the hypertension threshold may spare patients from escalation to medication. Maintenance trials can be harder to interpret than reduction studies, but they reflect a real preventive goal: preventing drift into higher-risk ranges over time.
That preventive frame is particularly important for interventions whose effects may be modest but cumulative. Changes in weight, dietary sodium intake, exercise habits, or combined lifestyle patterns may not create dramatic short-term shifts in blood pressure, yet they can still influence arterial load and long-term cardiovascular risk. The protocol is designed to capture that broader preventive value rather than limiting attention to short-term numerical change alone.
GRADE will be used where relevant to rate the certainty of the evidence. That step is essential because even a favorable effect estimate can be fragile if the underlying trials are small, inconsistent, or at high risk of bias. Evidence grading will help distinguish findings that are merely suggestive from those that are robust enough to inform clinical guidance.
Ethics are not required, but the dissemination plan is explicit
No ethical approval is needed because the project is a systematic review of existing studies. The results will be published in a peer-reviewed journal, shared on the study website, and disseminated to study sites and participants. In practical terms, that means the work is aimed not just at academic audiences but also at the communities and clinicians most likely to use the findings.
The unanswered issue is not whether prehypertension matters clinically — it does — but which non-drug strategies deliver the most dependable benefit, for whom, and at what cost. Until the review is complete, those questions remain open, and the value of the final synthesis will depend on whether the available trials are large enough, clean enough, and similar enough to support confident recommendations.