The effect of a vertically integrated health system on the disparity of socioeconomic status seen in cancer stage at presentation.

Abstract

1617 Background: Earlier stage of diagnosis may lead to more curable disease and less intensive treatment. Vertically integrated health care systems through screening and integrated care delivery model may provide benefit in identifying cancer patients at earlier stage of disease. Methods: We examined an insured Southern California cohort of 503,279 patients diagnosed with invasive cancer between Jan 1 2015 and Dec 31 2020 provided by the state SEER Cancer Registry. Stage at diagnosis provided was SEER summary stage in which patients were defined as having local disease or advanced (regional or metastatic) disease. We used geocoded socioeconomic status, race/ethnicity, and hospital of diagnosis as independent variables. For hospital of diagnosis, patients were divided into those diagnosed in Kaiser Foundation Hospitals or not. The first cohort was for cancers with robust screening programs and included breast, cervical and colon (CBC group). The second cohort was all other cancers (non CBC group). We evaluated each of these groups independently. The prevalence of local disease was determined and multilinear regression was used to determine the adjusted odd ratios of being diagnosed with local disease. Results: Compared to patients not diagnosed in Kaiser Foundation hospitals (non KFH), patients diagnosed in Kaiser Foundation hospitals (KFH) were more likely to be diagnosed with local disease. 1.14 (95% Confidence Intervals 1.13, 1.16) for the total cohort. We looked at the adjusted interaction of being diagnosed in KFH for each quintile: Highest SES 1.03 (1.00, 1.07), Upper Middle SES 1.11 (1.08, 1.14), Middle SES 1.21 (1.18, 1.25), Lower-Middle SES 1.25 (1.21, 1.29) and Lowest 1.34 (1.29, 1.38). Compared to patients not diagnosed in Kaiser Foundation hospitals (non KFH), patients diagnosed in Kaiser Foundation hospitals (KFH) were more likely to be diagnosed with local disease in the CBC cohort 1.12 (1.09, 1.16) and in the non CBC cohort 1.16 (1.14, 1.17). Conclusions: Vertically integrated health care systems have shown advantages in preventive care. We show that insured patients diagnosed in Kaiser Foundation hospitals present with more localized and less advanced disease than patients diagnosed in non KF hospitals. This advantage was seen in a group of patients with established screening program and was also seen in diseases without screening programs. A sub analysis showed that the advantage more pronounced the lower the SES. How a vertically integrated care delivery system provides these advantages deserves further study.