Hospital Quality for Acute Myocardial Infarction
Correlation Among Process Measures and Relationship With Short-term Mortality
- Elizabeth H. Bradley, PhD;
- Jeph Herrin, PhD;
- Brian Elbel, MPH;
- Robert L. McNamara, MD, MHS;
- David J. Magid, MD, MPH;
- Brahmajee K. Nallamothu, MD, MPH;
- Yongfei Wang, MS;
- Sharon-Lise T. Normand, PhD;
- John A. Spertus, MD, MPH;
- Harlan M. Krumholz, MD, SM
- Author Affiliations: Department of Epidemiology and Public Health (Drs Bradley and Krumholz and Mr Elbel), Section of Cardiovascular Medicine, Department of Medicine (Drs Herrin, McNamara, and Krumholz and Mr Wang), and Robert Wood Johnson Clinical Scholars Program (Drs Bradley and Krumholz),Yale University School of Medicine, and Yale-New Haven Hospital Center for Outcomes Research and Evaluation (Dr Krumholz), New Haven, Conn; Kaiser Permanente Clinical Research Unit, Aurora, Colo, and Department of Preventive Medicine and Biometrics and the Division of Emergency Medicine, University of Colorado Health Sciences Center, Denver (Dr Magid); Health Services Research and Development Center of Excellence, Ann Arbor Veterans Affairs Medical Center, and the Department of Internal Medicine, Division of Cardiovascular Disease, University of Michigan Medical School, Ann Arbor (Dr Nallamothu); Department of Health Care Policy, Harvard Medical School and Department of Biostatistics, Harvard School of Public Health, Boston, Mass (Dr Normand); Mid America Heart Institute and the University of Missouri–Kansas City (Dr Spertus).
- Corresponding Author: Harlan M. Krumholz, MD, SM, Yale University School of Medicine, 333 Cedar St, PO Box 208088, New Haven, CT 06520-8088 (harlan.krumholz{at}yale.edu).
Abstract
Context The Centers for Medicare & Medicaid Services (CMS) and the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) measure and report quality process measures for acute myocardial infarction (AMI), but little is known about how these measures are correlated with each other and the degree to which inferences about a hospital's outcomes can be made from its performance on publicly reported processes.
Objective To determine correlations among AMI core process measures and the degree to which they explain the variation in hospital-specific, risk-standardized, 30-day mortality rates.
Design, Setting, and Participants We assessed hospital performance in the CMS/JCAHO AMI core process measures using 2002-2003 data from 962 hospitals participating in the National Registry of Myocardial Infarction (NRMI) and correlated these measures with each other and with hospital-level, risk-standardized, 30-day mortality rates derived from Medicare claims data.
Main Outcome Measures Hospital performance on AMI core measures; hospital-specific, risk-standardized, 30-day mortality rates for AMI patients aged 66 years or older.
Results We found moderately strong correlations (correlation coefficients ≥0.40; P values <.001) for all pairwise comparisons between β-blocker use at admission and discharge, aspirin use at admission and discharge, and angiotensin-converting enzyme inhibitor use, and weaker, but statistically significant, correlations between these medication measures and smoking cessation counseling and time to reperfusion therapy measures (correlation coefficients <0.40; P values <.001). Some process measures were significantly correlated with risk-standardized, 30-day mortality rates (P values <.001) but together explained only 6.0% of hospital-level variation in risk-standardized, 30-day mortality rates for patients with AMI.
Conclusions The publicly reported AMI process measures capture a small proportion of the variation in hospitals' risk-standardized short-term mortality rates. Multiple measures that reflect a variety of processes and also outcomes, such as risk-standardized mortality rates, are needed to more fully characterize hospital performance.
