Prognostic factors for steroid-free remission in patients with idiopathic inflammatory myopathies: importance of anthropometric measurements.

BACKGROUND

Several studies have been conducted on factors associated with mortality in idiopathic inflammatory myopathies (IIMs), but few studies have assessed prognostic factors for steroid-free remission in IIM. We investigated the various clinical factors, including body measurements, that affect IIM treatment outcomes.

METHODS

Patients who were newly diagnosed with IIM between 2000 and 2018 were included. Steroid-free remission was defined as at least 3 months of normalisation of muscle enzymes and no detectable clinical disease activity. The factors associated with steroid-free remission were evaluated by a Cox regression analysis.

RESULTS

Of the 106 IIM patients, 35 displayed steroid-free remission during follow-up periods. In the multivariable Cox regression analyses, immunosuppressants' early use within 1 month after diagnosis [hazard ratio (HR) 6.21, 95% confidence interval (CI) 2.61-14.74,  < 0.001] and sex-specific height quartiles (second and third quartiles first quartile, HR 3.65, 95% CI 1.40-9.51,  = 0.008 and HR 2.88, 95% CI 1.13-7.32,  = 0.027, respectively) were positively associated with steroid-free remission. Polymyositis dermatomyositis (HR 0.21, 95% CI 0.09-0.53,  = 0.001), presence of dysphagia (HR 0.15, CI 0.05-0.50,  = 0.002) and highest lowest quartile of waist circumference (WC; HR 0.24, 95% CI 0.07-0.85,  = 0.027) were negatively associated with steroid-free remission.

CONCLUSION

The early initiation of immunosuppressant therapy, type of myositis and presence of dysphagia are strong predictors of steroid-free remission in IIM; moreover, height and WC measurements at baseline may provide additional important prognostic value.