Socioeconomic status and survival outcomes in elderly cancer patients: A national health insurance service‐elderly sample cohort study

Abstract Background We hypothesized that lower socioeconomic status (SES) was associated with higher all‐cause mortality in patients newly diagnosed with cancer, particularly in the elderly population. Methods We collected study patients from the stratified random sample of Korean National Health Insurance Elderly Cohort (2002‐2015). The Cox's proportional hazards model was used to investigate the risk factors for mortality. Income level and composite deprivation index (CDI) 2010 were used to define the SES: low, intermediate, and high SES groups. The comorbidities were measured using Charlson Comorbidity Index score. After a wash‐out period (2002), the final study population was 108 626 (2003‐2015). Results In multivariate analysis, low SES was associated with poor overall survival (OS) (HR = 1.08, 95% CI: 1.05‐1.12, P