Association of steroid regimens and withdrawal with relapse risk in myasthenia gravis: a real-world cohort study.

BACKGROUND

Corticosteroids (steroids) are the first-line immunotherapy for myasthenia gravis (MG), but the optimal steroid dosing regimen and effects of discontinuation remain unclear. This study aimed to investigate the associations of steroid regimens and steroid withdrawal with relapse risk in patients on steroid monotherapy.

METHODS

This cohort study, based on a prospective registry, included MG patients who achieved minimal manifestations or better status for at least 6 months with steroid monotherapy. The primary outcome was relapse. Group-based trajectory modeling (GBTM) identified steroid regimens, and Cox proportional hazards models with propensity score matching (PSM) assessed the association of regimens and steroid withdrawal with relapse.

RESULTS

Among 209 patients followed for a median of 54.0 months, 113 (54.1%) experienced relapses. GBTM identified three regimens reflecting baseline disease severity: "High Start, Fast Taper" (Regimen 1), "Moderate Start, Gradual Taper" (Regimen 2), and "Low Start, Slow Taper" (Regimen 3). Compared to the high-risk Regimen 1, Regimen 2 (HR = 0.27, p < 0.001) and Regimen 3 (HR = 0.15, p < 0.001) were associated with significantly lower relapse risks. A statistically determined cut-off analysis found that requiring a maximum induction dose >0.83 mg/kg to achieve MM or better status was a predictor of relapse (HR = 1.54, p = 0.033). Sixty-eight (32.5%) withdrew steroids, and PSM showed that steroid withdrawal significantly increased relapse risk versus low-dose maintenance (HR = 1.64, p = 0.009).

CONCLUSION

In this steroid-responsive population, patients requiring a maximum induction dose > 0.83 mg/kg to achieve MM or better status have a significantly higher risk of future relapse. Steroid withdrawal is associated with a higher relapse risk compared to low-dose maintenance and should be approached with caution.