Socioeconomic disparities and bladder cancer stage at diagnosis: a statewide cohort analysis.

Background: Bladder cancer is the ninth most common cancer worldwide. Despite its prevalence, large-scale studies on the relationship between socioeconomic disparities and disease stage at presentation are lacking. This study examines the association between the Area Deprivation Index (ADI), a robust measure of socioeconomic status, and stage at diagnosis among bladder cancer patients.

Methods: Patients diagnosed with bladder cancer (any TNM stage) from the Michigan Department of Health and Human Services (2004-2019) were retrospectively analyzed. ADI was assigned based on patients' residential census-block group and stratified into quartiles, with the fourth quartile (ADI 75-100) representing the most deprived. Multivariable logistic regression tested the impact of ADI on advanced disease stages (muscle invasive disease [≥T2], positive nodal status [cN+], metastatic disease [cM+]).

Results: Among 29 010 patients, the majority were non-Hispanic White (92%), males (75%), and residents in metropolitan areas (81%). Patients in the third and fourth ADI quartiles had higher rates of ≥T2 (22%, 24.5%) compared with the first and second quartiles (18%, 19.5%) (P < .001), as well as increased rates of cN+ (3.4%, 3.7%) and cM+ (2.8%, 3.2%) (P < .001). Multivariable regression showed that each 10-unit rise in ADI increased odds of T2 by 4% (95% CI = 1.03 to 1.06, P < .001), cN+ by 4% (95% CI = 1.01 to 1.07, P = .038), and cM+ by 6% (95% CI = 1.02 to 1.09, P = .003).

Conclusion: Higher ADI correlates with advanced bladder cancer stages at diagnosis. Addressing these disparities is essential to improve outcomes in bladder cancer care.