Disparities in Stage at Diagnosis in an Equal-access Integrated Delivery System: A Retrospective Cohort Study of 7244 Patients With Bladder Cancer

Abstract

Background: Disparities in bladder cancer survival by race/ethnicity and gender are likely related to differences in diagnosis. We assessed disparities in stage at diagnosis and potential contributing factors within a large, integrated delivery system. Patients and Methods: We conducted a retrospective cohort study of 7244 patients with bladder cancer age ≥ 21 years diagnosed from January 2001 to June 2015 within Kaiser Permanente Southern California. Bivariate analyses compared stage at diagnosis – as well as comorbidities, health plan membership length, and health care utilization prior to diagnosis – by race/ethnicity, gender, and age. Multivariable generalized linear mixed models with urologist as a random effect were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for diagnosis of muscle-invasive bladder cancer (MIBC) versus non–muscle-invasive bladder cancer. Results: In multivariable analyses, stage at diagnosis varied significantly by race/ethnicity (P