Statin-associated necrotising myopathy's excess mortality was no longer significant after adjustment for age and cardiometabolic disease

Design

Retrospective single-centre cohort

Population

142 adults with idiopathic inflammatory myopathy, 41 with statin-associated IMNM

Primary outcome

All-cause mortality

Effect

31.7% vs 23.8%; unadjusted HR 2.55 (1.24–5.24); fully adjusted HR 1.70 (0.71–4.08)

Statin-associated immune-mediated necrotising myopathy, with anti-HMGCR antibodies, is a distinct myositis that persists after the statin is stopped. This retrospective US cohort compared all-cause mortality in 41 such patients with 101 patients with other idiopathic inflammatory myopathies.

Crude mortality was higher (31.7% vs 23.8%; HR 2.55, 95% CI 1.24 to 5.24), with cardiopulmonary events and infection the main causes. The excess weakened after adjusting for age (HR 1.98, 0.97 to 4.03) and was no longer statistically significant after adding diabetes and hyperlipidaemia (HR 1.70, 0.71 to 4.08). Older patients with anti-HMGCR myopathy had the poorest survival.

The patient with statin-associated myopathy is usually older and cardiometabolically sick, and the authors read age and these comorbidities as marking a higher-risk group. The practical lesson is to treat the whole patient: aggressive myositis treatment, attention to cardiovascular risk now that statins are off the table, and vigilance for infection on immunosuppression.

• Check anti-HMGCR antibodies and CK in a statin user with proximal weakness that persists after stopping the statin.
• Treat anti-HMGCR myopathy as autoimmune disease requiring immunosuppression, not just statin withdrawal.
• Manage lipids with non-statin options (ezetimibe, PCSK9 inhibitors) and address cardiovascular risk actively.
• Screen for infection risk and vaccinate before intensifying immunosuppression in older patients.

Why it matters

Stopping statins removes cardiovascular protection in exactly the patients who most need it.

Don't overread it

After adjustment the excess mortality was not statistically significant; the myopathy itself is not shown to raise death risk.

The statistics, in plain English

An adjusted hazard ratio of 1.70 with a confidence interval from 0.71 to 4.08 includes 1.0, so the data are compatible with no extra mortality once age and comorbidity are accounted for.

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