Patterns of overall mortality by race/ethnicity and socioeconomic status in insured cancer patients in Southern California

PURPOSE: We evaluated the influence of race/ethnicity and geocoded socioeconomic status (SES) on all-cause mortality in cancer patients with health insurance. METHODS: We identified adults diagnosed with eight common cancers from 2009 to 2014 from the California Cancer Registry and followed them through 2017 (8 years maximum). We calculated person-year mortality rates by race/ethnicity and SES. Adjusted hazard ratios for the association between overall mortality and race/ethnicity and SES were estimated using Cox proportional hazards models accounting for other demographics, stage at diagnosis, and cancer treatments. RESULTS: A total of 164,197 adults were diagnosed with cancer originating from breast, prostate, lung, colon, skin melanoma, uterus, kidney, and bladder. For all race/ethnic groups combined, the mortality rates from lowest to highest SES groups were 112.1/1000 PY (lowest); 100.2/1000 PY (lower-middle); 91.2/1000 PY (middle); 79.1/1000 PY (upper-middle); and 63.5/1000 PY (upper). These rates suggest that person with lowest SES have a markedly increased mortality risk after cancer diagnosis even if they have health insurance. In multivariable analyses, those in the lowest SES group had a 40–78% increased risk of all-cause mortality compared to those in the upper SES group across all race/ethnicities. For example, within African Americans, the adjusted mortality risk was up to 61% higher (HR 1.61, 95% CI 1.41–1.83) in the lowest SES group compared to the highest SES group. CONCLUSION: This study suggests disparities in overall mortality risk after cancer diagnoses persist even in a cohort with health insurance, and that SES is an important driver of this disparity.