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

Abstract

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.