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Statin use may increase risk for idiopathic inflammatory myositis

Prior statin use was strongly associated with histologically confirmed idiopathic inflammatory myositis, according to research recently published in JAMA Internal Medicine.

“In the past 2 decades, numerous case reports have suggested that statins might also be associated with the development of inflammatory myositis,” Gillian E. Caughey, PhD, of the pharmacology discipline at the University of Adelaide in Australia and colleagues wrote.

“To date, no epidemiological studies have investigated exposure to statins in patients with histologically confirmed [idiopathic inflammatory myositis].”

Caughey and colleagues matched 221 patients with idiopathic inflammatory myositis with 662 patients in a population-based control group from an Australian database. The mean age of participants was 62.2 years and 59.7% were female.

Researchers found that there was a nearly twofold increased likelihood of statin exposure in patients with idiopathic inflammatory myositis vs. controls (adjusted OR = 1.79; 95% CI, 1.23-2.6). The results were nearly identical when patients with necrotizing myositis were removed from the analysis (aOR = 1.92; 95% CI, 1.29-2.86).

Caughey and colleagues noted previous research has shown the existence of HMG-CoA reductase antibodies in all subtypes of idiopathic inflammatory myositis, and these were “strongly associated” with exposure to statins.

“While the overall prevalence of these antibodies is low (9%) and their presence is not restricted to patients with previous statin use, these results support an association of statin exposure with all types of [idiopathic inflammatory myositis] .... Further research focusing on the specific types of [idiopathic inflammatory myositis] is required to elucidate the potential association with disease development and previous statin exposure and the potential role of HMG-CoA reductase antibodies,” they wrote.

Researchers added that though idiopathic inflammatory myositis and statin-associated autoimmune myopathy are rare, “increasing use of statins at the population level, the severity of this condition, and the need for immunosuppressive treatment highlights the importance of early recognition of this disease.” – by Janel Miller

Disclosure: Caughey reports no relevant financial disclosures. Please see the study for all the other authors’ relevant financial disclosures.