Changes in the Proportion of Patients Presenting with Early Stage Colon Cancer over Time among Medicaid Expansion and Nonexpansion States: A Cross-sectional Study

BACKGROUND: The 2010 Patient Protection and Affordable Care Act mandated preventive screening coverage and provided support to participating states for Medicaid coverage. The association of Medicaid expansion with colon cancer stage at diagnosis is unknown. OBJECTIVE: This study aimed to determine whether the proportion of patients diagnosed with early stage colon cancer changed over time within states that expanded Medicaid compared with nonexpansion states. DESIGN: This is a cross-sectional cohort study. SETTING: This study evaluated multicenter registry data from the National Cancer Database (2006-2016). PATIENTS: There were 25,462 uninsured or Medicaid-insured patients with newly diagnosed colon cancer who resided in 2014 Medicaid expansion or nonexpansion states. MAIN OUTCOME MEASURES: This study assessed the annual proportion of patients with early stage (I-II) versus late stage (III-IV) colon cancer. RESULTS: A total of 10,289 patients were identified in expansion states and 15,173 patients in nonexpansion states. Cohorts were similar in age (median 55 years) and sex (46.7% female). A greater proportion of patients in nonexpansion states were Black (33.4% vs 24.0%) and resided in a zip code with median income <$38,000 (39.7% vs 28.2%) and lower educational status (37.4% vs 28.1%). In 2006, the proportions of patients with early stage colon cancer in expansion and nonexpansion cohorts were similar (33.2% vs 32.5%). The proportion of patients with early stage colon cancer within nonexpansion states declined by 0.8% per year after 2014, whereas the proportion within expansion states increased by 0.9% per year after 2014 (p < 0.05). By 2016, the absolute difference in the propensity-adjusted proportion of early stage colon cancer was 8.8% (39.7% vs 30.9%, p < 0.001). LIMITATIONS: National Cancer Database data are obtained only from Commission on Cancer-accredited sites and are not population based. CONCLUSIONS: After Medicaid expansion in 2014, the proportion of patients diagnosed and treated at Commission on Cancer-accredited facilities with early stage colon cancer increased within expansion states and decreased in nonexpansion states. Increase in insurance coverage may have facilitated earlier diagnosis among patients in expansion states. See Video Abstract at http://links.lww.com/DCR/B804.