Association Between Medicare Expenditure Growth and Mortality Rates in Patients With Acute Myocardial Infarction

Abstract

Many studies have considered the association between Medicare spending and health outcomes at a point in time; few have considered the association between the long-term growth in spending and outcomes. To assess whether components of growth in Medicare expenditures are associated with mortality rates between January 1, 1999, and June 30, 2014, for beneficiaries hospitalized for acute myocardial infarction. Cross-sectional analysis of a random 20% sample of fee-for-service Medicare beneficiaries from January 1, 1999, through December 31, 2000 (n=72 473) and January 1, 2004, through December 31, 2004 (n=38 248), and 100% sample from January 1, 2008, through December 31, 2008 (n=159 558) and January 1, 2013, through June 30, 2014 (n=209 614) admitted with acute myocardial infarction to 1220 hospitals. Primary exposure measures include the growth of 180-day expenditure components (eg, inpatient, physician, and postacute care) and early percutaneous coronary intervention by hospitals adjusted for price differences and inflation. The primary outcome is the risk-adjusted 180-day case fatality rate. Patients in each of the years 2004, 2008, and 2013-2014 (relative to those in 1999-2000) were qualitatively of equivalent age, less likely to be white or female, and more likely to be diabetic (all P < .001). Adjusted expenditures per patient increased 13.9% from January 1, 1999, through December 31, 2000, and January 1, 2013, through June 30, 2014, but declined 0.5% between 2008 and 2013-2014. Mean (SD) expenditures in the 5.0% of hospitals (n = 61) with the most rapid expenditure growth between 1999-2000 and 2013-2014 increased by 44.1% ($12 828 [$2315]); for the 5.0% of hospitals with the slowest expenditure growth (n = 61), mean expenditures decreased by 18.7% (-$7384 [$4141]; 95% CI, $8177-$6496). The growth in early percutaneous coronary intervention exhibited a negative association with 180-day case fatality. Spending on cardiac procedures was positively associated with 180-day mortality, while postacute care spending exhibited moderate cost-effectiveness ($455 000 per life saved after 180 days; 95% CI, $323 000-$833 000). Beyond spending on noncardiac procedures, growth in other components of spending was not associated with health improvements. Health improvements for patients with acute myocardial infarction varied across hospitals and were associated with the diffusion of cost-effective care, such as early percutaneous coronary intervention and, to a lesser extent, postacute care, rather than overall expenditure growth. Interventions designed to promote hospital adoption of cost-effective care could improve patient outcomes and, if accompanied by cuts in cost-ineffective care (inside and outside of the hospital setting), also reduce expenditures.