Higher admission WBC predicts favorable methylprednisolone effect after thrombectomy

This study represents a secondary analysis of a randomized, placebo-controlled trial involving 1201 patients. The population consisted of individuals with anterior-circulation large-vessel occlusion stroke who achieved successful reperfusion after thrombectomy. The setting location was not reported. The primary investigation focused on the relationship between admission white blood cell counts and the estimated treatment effects of adjunctive methylprednisolone compared with placebo. The follow-up period extended for 90 days. The study design allowed for the assessment of how baseline inflammatory markers might modify the response to corticosteroid therapy in this specific stroke cohort.

The intervention involved the administration of adjunctive methylprednisolone. The comparator group received placebo. Specific dosing protocols for the methylprednisolone were not detailed in the provided data. The primary outcome measured was the 90-day modified Rankin Scale (mRS 0-6). This scale assesses disability levels ranging from no symptoms to death. Secondary outcomes included mRS 0-3, mRS 0-4, early NIHSS, mortality, symptomatic intracranial hemorrhage (sICH), any intracranial hemorrhage, pneumonia, and gastrointestinal bleeding.

Analysis of the 90-day ordinal mRS distribution revealed that results were more favorable in patients with WBC greater than or equal to 10 times 10 to the power of 6 per liter. The adjusted common odds ratio for this favorable outcome was 1.59. The 95% confidence interval for this effect size ranged from 1.11 to 2.28. The p-value for this association was not explicitly reported as a single number in the primary outcome section, but the direction was noted as favorable. Mortality was lower in patients with WBC greater than or equal to 10 times 10 to the power of 6 per liter. The adjusted odds ratio for mortality was 0.60. The 95% confidence interval for this mortality reduction ranged from 0.37 to 0.96. Pneumonia rates were also lower in this high WBC group. The adjusted odds ratio for pneumonia was 0.61. The 95% confidence interval for pneumonia ranged from 0.40 to 0.93.

A treatment by WBC interaction was assessed to determine if the effect of methylprednisolone differed by baseline WBC level. This interaction showed nominal statistical significance with a p-value of 0.04. The direction of this interaction was not reported in the provided data. Safety and tolerability findings indicated that there was no apparent increase in hemorrhage or gastrointestinal bleeding. Specific adverse event rates, serious adverse event counts, and discontinuation numbers were not reported in the source data. The study did not report specific rates for symptomatic intracranial hemorrhage or any intracranial hemorrhage as absolute numbers, only as secondary outcomes.

These results compare to prior landmark studies by suggesting that inflammatory markers may predict response to adjunctive therapy. However, the study is a post hoc secondary analysis, which warrants prospective validation. The practice relevance indicates that higher admission WBC was associated with more favorable estimated treatment effects from adjunctive methylprednisolone after thrombectomy. This association must be interpreted with caution because the study design does not establish causality. The distinction between surrogate markers and clinical outcomes remains important in this context.

Key methodological limitations include the post hoc nature of the analysis and the lack of prospective validation. Potential biases inherent in secondary analyses were not fully detailed. The study did not report funding sources or conflicts of interest. Questions remain unanswered regarding the optimal WBC threshold for treatment selection and the long-term implications of this association. The evidence is observational in nature regarding the WBC interaction, so causal language is avoided. Clinicians should consider these findings as hypothesis-generating rather than definitive proof of efficacy modification.