Biological Mechanism of Sclerostin Inhibition and Cardiovascular Risk

confidence: high · 3 sources

⚠
Working research — not a recommendation.

This page records what the evidence says a policy does, not what anyone should do about it. It has been synthesized from the cited sources but has not been independently reviewed.

What the evidence says

Romosozumab inhibits sclerostin, an endogenous inhibitor of Wnt signaling. Sclerostin lies at the interface between skeletal anabolism and vascular mineralization, so a cardiovascular question follows from the bone mechanism. The sources here describe that link but do not show how it would produce cardiovascular harm.

In postmenopausal women with osteoporosis, romosozumab markedly reduced vertebral and clinical fractures in the placebo-controlled FRAME trial. Cardiovascular events appeared balanced between treatment groups in that trial. In the active-comparator ARCH trial, romosozumab followed by alendronate reduced vertebral, clinical, nonvertebral, and hip fractures more than alendronate alone. Positively adjudicated serious cardiovascular adverse events during the first year were numerically more frequent in the romosozumab group. The sources do not say whether this reflects drug harm, an alendronate benefit, or chance.

Genetic evidence points toward higher cardiovascular risk. SOST variants associated with sclerostin inhibition were linked to lower fracture and osteoporosis risk, and to a higher risk of myocardial infarction and/or coronary revascularization and major adverse cardiovascular events. The same variants were linked to higher type 2 diabetes risk, higher systolic blood pressure, and more central adiposity. A 2024 cis-Mendelian randomization study likewise tied genetically predicted lower sclerostin to excess coronary artery disease risk and adverse cardiometabolic biomarker profiles. A meta-analysis of up to three RCTs indicated a probable higher risk of cardiovascular events with romosozumab. None of these sources gives an effect size in the text quoted here.

Other evidence points the other way or is weaker. A 2024 real-world cohort found no increase in major adverse cardiovascular events during treatment, though absolute rates were higher in patients with pre-existing cardiovascular disease or diabetes. A pharmacovigilance analysis of FAERS detected disproportionate reporting of major adverse cardiovascular events, but spontaneous reports cannot establish causality. Histology of advanced human plaques shows sclerostin is not expressed in the fibrous cap or endothelium. Nonclinical atherosclerosis models and patients with sclerosteosis, who have lifelong sclerostin deficiency, show no evidence of premature cardiovascular disease.

Where the evidence splits

The genetic studies and the trial meta-analysis point to higher cardiovascular risk. The FRAME trial, the real-world cohort, the plaque histology, and the sclerostin-deficiency observations show no increase or no mechanism. The sources on this page do not explain the split.

They do supply some design differences. The genetic and meta-analytic findings concern lifelong genetically lower sclerostin or pooled trial data. The deficiency observations come from mouse models and sclerosteosis patients. The real-world cohort is observational and limited by confounding and short follow-up. The sources do not state which difference, if any, accounts for the disagreement. The ARCH signal is a single-trial finding with no clear causal reading.

Thresholds and dose-response

No threshold established in the current sources.

Open empirical questions

Findings

Romosozumab decreases vertebral and clinical fractures in postmenopausal women with osteoporosis

confidence — direction: highconfidence — magnitude: highconsensus: settled
mechanism
inhibition of sclerostin, an endogenous Wnt signaling inhibitor
effect
decreases vertebral and clinical fractures versus placebo (FRAME); decreases vertebral, clinical, nonvertebral, and hip fractures versus alendronate alone (ARCH). No magnitude given in the claims.
conditions / moderators
postmenopausal women with osteoporosis

Romosozumab trials show mixed evidence on serious cardiovascular events

confidence — direction: lowconfidence — magnitude: lowconsensus: contested
mechanism
not established; the cause of the ARCH signal is unclear
effect
FRAME: events appeared balanced between groups. ARCH: positively adjudicated serious cardiovascular adverse events in year one were numerically more frequent with romosozumab than alendronate. A meta-analysis of up to three RCTs indicated a probable higher risk of cardiovascular events. No magnitudes given.
conditions / moderators
the ARCH finding is first-year and from a single trial; the meta-analysis wording is "probable"

Genetically lower sclerostin increases coronary artery disease, myocardial infarction, and MACE risk

confidence — direction: mediumconfidence — magnitude: lowconsensus: contested, because sclerostin-deficiency observations show no premature cardiovascular disease
mechanism
not established; genetic evidence does not show that drug inhibition produces the same effect
effect
increases risk of myocardial infarction and/or coronary revascularization and major adverse cardiovascular events; increases coronary artery disease risk and adverse cardiometabolic biomarker profiles. No magnitude given.
conditions / moderators
relies on Mendelian randomization assumptions

Genetically lower sclerostin increases type 2 diabetes risk, systolic blood pressure, and central adiposity

confidence — direction: highconfidence — magnitude: lowconsensus: thin
mechanism
not established
effect
increases type 2 diabetes risk, systolic blood pressure, and central adiposity. No magnitude given.
conditions / moderators
genetic association; not tested for pharmacologic inhibition in these claims

Real-world romosozumab use shows no measured increase in major adverse cardiovascular events overall

confidence — direction: mediumconfidence — magnitude: lowconsensus: thin
mechanism
not established
effect
no measured effect on major adverse cardiovascular events during treatment; absolute event rates were higher in patients with pre-existing cardiovascular disease or diabetes
conditions / moderators
observational design, vulnerable to confounding by indication and allocation bias; limited follow-up

Pharmacovigilance reports show disproportionate reporting of cardiovascular events with romosozumab

confidence — direction: lowconfidence — magnitude: lowconsensus: thin
mechanism
not established; spontaneous reports cannot establish causality
effect
disproportionate reporting of major adverse cardiovascular events detected in FAERS. No magnitude given.
conditions / moderators
subject to reporting bias, selection bias, and confounding

Sclerostin deficiency shows no measured increase in cardiovascular disease, and sclerostin is absent from plaque-critical regions

confidence — direction: mediumconfidence — magnitude: lowconsensus: contested, because genetic association studies point to higher cardiovascular risk
mechanism
sclerostin is not expressed in the fibrous cap or endothelium of advanced human plaques, so no direct local mechanism was identified
effect
no measured effect on cardiovascular disease in ovariectomized and apolipoprotein E knockout mouse models or in patients with sclerosteosis
conditions / moderators
whether absent local expression and absent disease rule out a cardiotoxic mechanism is not established