Socioeconomic disparities in IDH-wildtype glioblastoma survival: interactions between age and household income in a SEER cohort

Abstract

Background: Glioblastoma multiforme (GBM) remains an aggressive brain tumor with a poor prognosis. The financial burden of GBM have raised concerns about accessibility and equity in care. We performed a cohort study to evaluate the impact of household income on survival outcomes in patients with IDH-wildtype GBM. Methods: Patients diagnosed with IDH-wildtype GBM from 2018 to 2021 were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database and categorized into low-, middle-, and high-income groups based on household income. Univariate and multivariate Cox regression models were used to analyze survival data and evaluated by hazard ratios (HRs) and 95% confidence intervals (CI). Further analyses of interaction effects were also performed. Results: In total, 6190 patients with IDH-wildtype GBM were included with a median survival of 12.52 months. Multivariate analysis revealed that middle- and high-income patients had significantly better survival outcomes compared to low-income patients (overall survival: HR 0.881 (0.816–0.951), p = 0.001, HR 0.860 (0.792–0.934), p < 0.001; GBM-specific survival: HR 0.866 (0.799–0.937), p < 0.001, HR 0.854 (0.784–0.929), p < 0.001). Such disparities in survival widened over time, particularly for GBM-specific survival. An interaction effect was also found between household income and age, with older, low-income patients with IDH-wildtype GBM showing significantly worse outcomes. Conclusion: Household income is an independent predictor of survival in patients with IDH-wildtype GBM. Disparities in outcomes are widening over time, and targeted interventions are needed to address the socioeconomic barriers to treatment, particularly for older, low-income patients.