DOI: 10.4103/nsn.nsn_16_26 ISSN: 2636-865X

Preoperative Myasthenia Gravis Composite Score Cutoff Predicts Poor Outcome after Thymectomy in Acetylcholine Receptor Antibody-positive Myasthenia Gravis

Ahmet Yusuf Erturk, Inci Sule Özer, Ihsan Sükrü Sengün

A
BSTRACT

Background:

Thymectomy is an established therapeutic approach in myasthenia gravis (MG) and provides clinical benefit in selected patient populations. Nevertheless, long-term outcomes remain variable among patients with acetylcholine receptor (AChR) antibody positivity, irrespective of thymoma status.

Objective:

To assess postthymectomy clinical outcomes and determine prognostic factors associated with relapse in patients with AChR antibody-positive MG.

Methods:

A retrospective analysis was performed on 41 adult patients with AChR antibody-positive MG who underwent video-assisted thoracoscopic thymectomy between 2012 and 2024. All patients had received immunomodulatory treatment for at least 6 months before surgery. Disease severity was evaluated using MG composite (MGC) scores and MG foundation of America (MGFA) clinical classification at baseline, at 1 year postoperatively, and at the final follow-up visit. Clinical outcomes were classified as complete stable remission (CSR), pharmacologic remission (PR), or exacerbation.

Results:

At the final follow-up, CSR was achieved in 17.1% of patients, 41.5% were in PR, and 41.5% experienced disease exacerbation. MGC scores showed a significant reduction at the 1-year follow-up compared with baseline ( P < 0.001). Poor clinical outcomes were significantly associated with higher baseline MGC scores and more advanced MGFA stages ( P = 0.026 and P = 0.03, respectively). Receiver operating characteristic analysis demonstrated that a baseline MGC score of 12.5 or higher was a moderate predictor of poor clinical outcome ( P = 0.013).

Conclusion:

Thymectomy was associated with meaningful clinical improvement in patients with AChR antibody-positive MG, particularly during the first postoperative year. An elevated baseline MGC score (>12.5) was independently associated with an increased likelihood of poor clinical prognosis.

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