Inflammation Markers Fail to Predict Post-thymectomy Myasthenic Crisis: A Retrospective Analysis

Background: Post-thymectomy myasthenic crisis (POMC) significantly increases acute morbidity and resource utilization in myasthenia gravis (MG) patients. While established clinical factors, such as acetylcholine receptor antibody (AChR-Ab) titer and Bulbar symptoms are known predictors, the utility of easily accessible systemic inflammatory markers, such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), immune-inflammation index (SII), and systemic inflammatory response index (SIRI) in POMC risk stratification, especially compared to clinical variables, remains poorly defined in the literature. Aim: We aimed to evaluate and compare the preoperative predictive performance of established MG-specific clinical parameters versus systemic inflammatory biomarkers for identifying independent risk factors of POMC. Methods: This retrospective study enrolled a highly curated cohort of 49 MG patients who underwent thymectomy between 2012 and 2021. Patients with confounding acute infections or systemic immunomodulation were also excluded. The primary outcome was POMC (defined as the requirement for mechanical ventilation within 30 days post-surgery). Univariate and multivariate logistic regression models were constructed to compare the predictive power of the five inflammatory indices (NLR, PLR, LMR, SII, and SIRI) against established MG clinical parameters (bulbar symptoms, MG Foundation of America Clinical Classification >3, and AChR-Ab titer). Overall survival (OS) was assessed using Kaplan–Meier analysis. Results: The final cohort of 49 patients (16, 32.7%) developed POMC. In the univariate analysis, bulbar symptoms (odds ratio[OR] = 9.00, P < 0.001) and AChR-Ab positivity (OR = 3.85, P = 0.03) were significant predictors. In the multivariate model, bulbar symptoms remained the sole independent predictor (OR = 12.45, P = 0.06). All five systemic inflammatory markers (NLR, PLR, LMR, SII, and SIRI) failed to show a significant association with POMC risk (all P > 0.1). POMC did not significantly affect the long-term OS ( P = 0.25), with the non-POMC group having a 10-year OS of 90% versus 83% for the POMC group. Conclusion: Bulbar symptoms showed a strong trend as a potential predictor of POMC following thymectomy. Systemic inflammatory indices derived from complete blood count, such as NLR, PLR, SII, and SIRI, lacked statistically significant predictive utility for this acute outcome. These results advocate the prioritization of rigorous preoperative neurological optimization in bulbar symptomatic patients over reliance on hematological inflammatory biomarkers for risk stratification.