Thymectomy for non-thymomatous myasthenia gravis: a propensity score matched study

Abstract

BackgroundThe efficacy of thymectomy in patients with non-thymomatous Myasthenia Gravis (MG) is still unclear. Main limitations have been variable outcome definitions, lack of a control group and adjustment for confounding.ObjectiveTo study the efficacy of thymectomy in achieving remission or minimal manifestation (R/MM) status in patients with non-thymomatous MG.MethodsPatients with generalized MG and minimum follow-up of 6 months were included. Demographic data and treatments were recorded, as well as the MGFA post-intervention status at the last visit. Propensity scores were used to create a matched cohort of treated and untreated patients. Standard and Bayesian Cox models were used to study treatment effects.ResultsOf 395 patients included, 183(46%) had a thymectomy. Thymectomy patients were younger (p < 0.001), with more females (p < 0.001) and more patients in MGFA classes 4–5 at diagnosis (p = 0.01). A matched cohort of thymectomized patients and controls (n = 98) was created. The hazard ratio (HR) for the matched cohort was 1.9 (CI:1.6-2.3), favoring thymectomy. The predicted R/MM rate was 21% in treated and 6% in controls at 5 years (Absolute difference:15%). A Bayesian Cox model for the matched cohort had an estimated probability of thymectomy efficacy (HR > 1) of 96% using a non-informative prior, and 79% using a skeptical prior.DiscussionWhen controlling for potential confounders, thymectomized patients had a higher probability of achieving R/MM status through time compared to controls. This study provides class III evidence of the efficacy of thymectomy in non-thymomatous myasthenia gravis.

Improved outcomes with surgery vs. medical therapy in non-thymomatous myesthenia gravis: a perspective on the results of a randomized trial

“…Several large retrospective data sets indicate that there is a significant increase in achieving minimal symptoms or remission in MG patients who had a thymectomy performed (2,3). Propensity matched data also supports these findings (4). These data sets are confounded by differences in surgical technique, lack of prospective randomization and limited follow up.…”

The role of plasmapheresis in prevention of complications after thoracoscopic thymectomy in patients with myasthenia combined with thymic hyperplasia

“…Незначительное ухуд-шение состояния больных с миастенией после опе-ративного вмешательства, не получавших в пред-и послеоперационных периодах плазмаферез, под-тверждает предположение некоторых авторов [8] о влиянии именно плазмафереза на состояние паци-ента в ближайшем послеоперационном периоде, не-жели непосредственно ТЭ как фактора, уменьшаю-щего клинические проявления миастении. Из паци-ентов, не вошедших в исследование, выделим 2 больных, которым в качестве предоперационной подготовки проводилась инфузия иммуноглобули-нов.…”

Myasthenia Gravis

“…108 Another large retrospective study investigated the efficacy of thymectomy in nonthymomatous GMG and reported a 21% rate of remission or minimal manifestations in the thymectomy group at 5 years, compared with 6% in the control group. 109 The authors concluded that their study provides class III evidence of the efficacy of thymectomy in nonthymomatous MG. Longer duration of follow-up is associated with even higher rates of CSR, and has been reported to be as high as 72% at 10 years. 110 Despite these reports, the effectiveness of thymectomy is not universally embraced.…”