Large US cohort compares GLP-1 drugs with spironolactone in resistant hypertension

A new retrospective study published in eClinicalMedicine compares two very different treatment paths for people with resistant hypertension and overweight or obesity: starting a GLP-1 receptor agonist such as semaglutide (Ozempic, Wegovy) or tirzepatide (Mounjaro, Zepbound), versus starting a mineralocorticoid receptor antagonist (MRA), a class that includes spironolactone, as a fourth-line blood pressure drug ^[1].

The study drew on the TriNetX US Collaborative Network, a database that pools electronic health records from 67 healthcare organizations across the country ^[1]. Researchers identified 213,309 eligible adult patients before they applied statistical matching to make the two treatment groups more comparable ^[1]. The main outcome the researchers tracked was major adverse cardiovascular events, a composite measure that typically includes things like heart attack, stroke, and cardiovascular death, over a two-year follow-up period ^[1].

In this analysis, semaglutide and tirzepatide were grouped together and compared as a single GLP-1 category against MRA therapy, rather than being examined as separate drugs ^[1]. The source material provided does not include the specific event rates, hazard ratios, or confidence intervals that would show whether one treatment group had fewer cardiovascular events than the other. That means the actual comparative results of this study are not established from what is available here.

The study's authors flag confounding by indication as the central limitation of their design ^[1]. This is a common problem in studies that use existing medical records rather than randomly assigning patients to treatments. Doctors may have chosen a GLP-1 drug or an MRA for reasons tied to a patient's overall health, weight, kidney function, or other conditions, and those same factors could independently affect the risk of heart problems. That makes it hard to know how much of any difference in outcomes came from the drugs themselves versus from why patients were prescribed one treatment over another in the first place.

Why it matters for patients

Resistant hypertension, blood pressure that stays high despite three or more medications, is a difficult problem, and doctors often add a fourth drug such as spironolactone once diuretics and other standard options are not enough ^[1]. GLP-1 drugs like semaglutide and tirzepatide are approved for type 2 diabetes and, in some formulations, for weight management, and they are known to lower blood pressure somewhat as a side effect of weight loss and other mechanisms. This study is notable because it directly stacks GLP-1 therapy up against an established fourth-line blood pressure drug in a real-world US patient population rather than in a clinical trial.

However, because this is an observational study built from insurance and health-system records, and because the researchers themselves point to confounding by indication as a major weakness, patients and clinicians should treat any findings from this type of research as preliminary evidence rather than proof that one approach is better than the other ^[1]. Real-world data studies like this one can raise useful questions and guide the design of future randomized trials, but they generally cannot settle the question of which treatment causes better or worse outcomes.

What happens next

The study has been published in eClinicalMedicine ^[1]. Based on the materials available, it is not yet known whether follow-up randomized controlled trials directly comparing GLP-1 drugs with MRAs for resistant hypertension are planned, or when such results might become available. Readers with resistant hypertension who are curious about how this research might apply to their own care should discuss it with their treating physician.