GLP-1 drugs shaved a few mmHg off blood pressure

GLP-1 receptor agonists were developed for type 2 diabetes and are now widely used for weight loss, which has raised the question of what else they shift across the cardiometabolic picture. Blood pressure is an obvious candidate, since weight loss usually lowers it, but the authors note the evidence specifically on blood pressure has been sparse. Knowing whether these drugs reliably reduce pressure, and by how much, matters for judging their place alongside established antihypertensive treatment and lifestyle change.

The team searched PubMed, EMBASE and CENTRAL from inception to 13 February 2024 for randomised controlled trials of GLP-1 receptor agonists in overweight or obese patients. Thirty randomised controlled trials with a combined population of 37 072 patients were pooled. Pairwise meta-analysis was combined with random-effects meta-regression, and a fixed-effects model was used to unify treatment effects across different drug doses. Subgroups covered diabetic status, drug formulation, follow-up duration and route of administration.

Systolic blood pressure fell by 3.37 mmHg (95% CI -3.95 to -2.80) and diastolic by 1.05 mmHg (95% CI -1.46 to -0.65) compared with placebo. The direction and significance of the effect held across every subgroup examined for both systolic and diastolic pressure, apart from the subgroups investigating exenatide. Meta-regression found no significant relationship between blood pressure reduction and baseline characteristics including age, the proportion of male patients, HbA1c, weight, body mass index or the proportion of patients with hypertension.

This fills a gap the authors describe as sparse, and it suggests the blood pressure effect is a fairly general property of the drug class rather than something confined to people with diabetes or to a particular formulation or injection schedule. The absence of any relationship with baseline weight or body mass index in meta-regression is notable, because it argues against the reduction being a straightforward consequence of how heavy someone was to begin with. Open questions remain about the exenatide exception, about whether pressure changes persist after treatment stops, and about how these millimetres translate into cardiovascular events.

The reduction here is real but small in absolute terms: a few millimetres of mercury on systolic pressure, roughly one on diastolic. That is worth knowing if you are taking or considering one of these medicines, because it means blood pressure may drift down as a side effect of treatment rather than staying put. It also means these drugs are not a substitute for the things that move pressure more, and their use belongs in a conversation with the prescriber who monitors it. This is a class-level average, so individual responses will vary.