Improved quality and cost-effectiveness of coronary artery bypass grafting in the United States from 1988 to 2005

Objective: This study was undertaken to assess the impact of increasing patient complexity and health care cost on coronary artery bypass grafting quality and cost-effectiveness in the United States over an 18- year period. Methods: A retrospective study was carried out utilizing the Nationwide Inpatient Sample to track the characteristics and outcomes of 5,549,700 patients having isolated coronary artery bypass grafting in the United States from 1988 to 2005. Expected mortality, risk-adjusted mortality, and hospital charges were tracked over this period. Results: The prevalence of congestive heart failure, pulmonary disease, diabetes, and acute myocardial infarction increased significantly over the study period. Expected mortality increased from 2.57% to 3.66%, reflecting the increasing patient comorbidity burden (P<.0001). Despite this, coronary artery bypass grafting outcomes improved, leading to a decrease in risk-adjusted mortality from 6.20% to 2.12% (P<.0001). Furthermore, when hospital charges were corrected for medical care inflation, hospital charges declined significantly, from $ 26,210 in 1988 to $ 19,196 in 2005 (1988 dollars, P<.0001). Conclusions: Coronary artery bypass grafting surgery is being performed on an increasingly complex, high-risk patient population in the United States. Despite this challenge, risk-adjusted operative mortality has progressively declined. Moreover, hospital charges for coronary artery bypass grafting in relation to other medical care services have been reduced. These findings reflect improved quality and cost-effectiveness of coronary artery bypass grafting in the United States. Ongoing efforts directed at quality improvement should address the risks associated with comorbidities that increasingly accompany the diagnosis of coronary artery disease in patients having coronary artery bypass grafting.