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

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.

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+]).

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).

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