Myositis overlap in systemic sclerosis was linked to markedly more cardiac involvement

Design

Single-centre retrospective cohort with 1:1 propensity matching

Population

184 matched patients with systemic sclerosis (92 with myositis) from a cohort of 880

Primary outcome

Cardiac involvement and mortality

Effect

Cardiac involvement aOR 19.99 (2.19-182.26); cardiac involvement and death aHR 8.09 (1.36-48.26)

A single-centre retrospective cohort of 880 patients with systemic sclerosis (Rheumatology, 16 October 2026) identified 92 (10.4%) with overlapping myositis, defined as proximal weakness with raised muscle enzymes and no other cause. Each was propensity-matched to a patient without myositis.

Myositis was strongly associated with cardiac involvement by Scleroderma Clinical Trials Consortium criteria (pericardial effusion, ventricular dysfunction, arrhythmia or conduction disease): adjusted OR 19.99 (95% CI 2.19-182.26), or 12.84 (2.31-98.47) with a penalised model. Higher skin score also predicted cardiac disease. Overall mortality did not differ over a median 21 months (13.0% vs 9.8%), but cardiac involvement itself was associated with death (adjusted HR 8.09, 1.36-48.26). Deaths in the myositis group were more often cardiac and none were from interstitial lung disease.

The effect size is imprecise, but the direction is consistent with what is known about myocardial involvement in inflammatory myopathy. Patients with systemic sclerosis and raised muscle enzymes deserve a deliberate cardiac work-up.

• Check creatine kinase in systemic sclerosis, especially with proximal weakness.
• In systemic sclerosis with myositis, arrange ECG, echocardiography and consider Holter monitoring.
• Consider cardiac MRI where symptoms, ECG or troponin suggest myocardial involvement.
• Reassess cardiac status periodically rather than only at diagnosis.
• Remember that cardiac involvement, not myositis itself, was the factor linked to death.

Why it matters

It shifts attention in this subgroup from the lungs to the heart, where deaths were concentrated.

Don't overread it

The confidence intervals span more than tenfold, and the study cannot show myositis causes cardiac disease.

The statistics, in plain English

An OR of 20 with a CI from 2 to 182 means the association is clearly present but its size is very uncertain, as expected with few events. The penalised (Firth) model, designed for small samples, gave a lower but still large estimate.

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