Associations of Early Medicaid Expansion and Cancer Mortality

Abstract

There is a growing body of evidence that Medicaid expansion improves insurance rates and leads to earlier cancer diagnoses. However, there is no published data to date showing an improvement in survival or mortality for cancer patients. Our objective was to determine whether early Medicaid expansion (2010-2011) was associated with decreased cancer mortality rates. Mortality rates were obtained from the Surveillance, Epidemiology, and End Results (SEER) program in the year ranges available in SEER: 2005-2007 (pre-expansion) and 2012-2016 (post-expansion). Deaths in 2008-2011 were excluded as a phase-in/washout period. Difference-in-differences (DID) analyses were utilized to compare changes in mortality rates from pre- to post-expansion between early expansion (EXP states: CA, CT, DC, MN, NJ, and WA) and non-early expansion states (NEXP states: all others). Adjusted DID analyses were based on county-year group level observations and accounted for county-level covariates. Mortality rates were calculated for all malignancies combined, screenable cancers, and cancer sites with leading causes of death. To ensure minimal confounding due to differing mortality trends between EXP and NEXP states (i.e. to test the parallel trends assumption), changes in cancer mortality rates from 2002-2004 to 2005-2007 and from 2005-2007 to 2008-2011 were compared between EXP and NEXP states. There were 270,150 and 1,148,638 cancer deaths in EXP and NEXP states, respectively. Cancer mortality rates (rate = # deaths / 100,000 persons) declined in both EXP (rate = 75.7 pre-expansion to 64.7 post-expansion) and NEXP (rate = 88.0 to 77.9) states after early Medicaid expansion. In adjusted DID analyses, there was a reduction of 1.30 (95% CI = 0.62 to 1.99, P = .0001) cancer deaths/100,000 persons in EXP relative to NEXP states. Significant expansion-associated reductions were observed for liver and pancreas but not colon, breast, cervix, lung, or prostate cancers (Table). While there was a decrease in cancer mortality irrespective of expansion status, early Medicaid expansion was associated with a decrease of 1.3 cancer deaths per 100,000 persons, translating to about 900 cancer deaths prevented in early expansion states due to Medicaid expansion (based on 2013 EXP states population = 69.2M). As more data emerge, future studies should describe longer-term trends in mortality post-Medicaid expansion.Abstract 202; TableAdjusted DID estimates by cancer siteDID Estimate (95% CI)PAll Malignancies-1.30 (-1.99, -0.62)<0.001Breast0.21 (-0.24, 0.66)0.36Cervix-0.20 (-0.41, 0.02)0.076Colon0.06 (-0.14, 0.28)0.52Liver-0.23 (-0.39, -0.07)0.006Lung0.18 (-0.13, 0.50)0.25Pancreas-0.22 (-0.38, -0.05)0.012Prostate-0.18 (-0.39, 0.02)0.082 Open table in a new tab