Better Quality of Care Tied to Drop in Acute MI Mortality

October 2009

Improvements Occurred Despite The Increased Prevalence Of Comorbidities Such As Hypertension, Diabetes, And Renal Disease

By Mary Ann Moon
Elsevier Global Medical News

Thirty-day mortality among patients hospitalized with acute myocardial infarction markedly decreased in the United States between 1995 and 2006, according to a report in JAMA.

This decrease occurred even though the AMI population had a concomitant increase in age and comorbid conditions, and against a background in which mortality for non-AMI admissions did not change substantially, said Dr. Harlan M. Krumholz of Yale University, New Haven, and his associates.

This interval has been a "period of marked emphasis on improving the quality of hospital care for patients with AMI." But until now, data have been scarce as to whether hospitals were achieving better short-term mortality rates for AMI or if there was a reduction in between-hospital variation in short-term mortality rates.

The investigators used Medicare data on 3,195,672 discharges to examine 30-day risk-standardized mortality in more than 4,000 nonfederal acute care hospitals across the country. The mean patient age was 78 years.

Thirty-day all-cause mortality in AMI patients decreased from 18.9% in 1995 to 16.1% in 2006, a relative reduction of nearly one-sixth. In-hospital mortality decreased from 14.6% to 10.1%, while 30-day mortality for all other patients remained steady at approximately 9%.

"Among Medicare beneficiaries, for every 33 patients admitted in 2006, compared with 1995, there was 1 additional patient alive at 30 days," according to Dr. Krumholz and his colleagues (JAMA 2009;302:767-73). This improvement occurred even though the prevalence of comorbidities rose, including that of hypertension, diabetes, renal disease, and chronic obstructive pulmonary disease. Moreover, AMI patients in recent years were more likely than were those in the mid-1990s to have a history of previous MI, percutaneous coronary intervention, and coronary artery bypass grafting.

Over time, there also was a marked decrease in the variation in mortality between hospitals. In the mid-1990s, 39 hospitals had very high AMI mortality, and the poorest performing 1% of hospitals had AMI mortality exceeding 24%. "By 2006, there was no hospital in this group, and the worst 1% of hospitals had a 30-day risk-standardized mortality of 19.5%," the researchers noted.

This study was not designed to examine why these improvements occurred, but they likely reflect "the success of the many individuals and organizations dedicated to improving AMI care during this period," the investigators added.

This study was funded by the Centers for Medicare and Medicaid Services, U.S. Department of Health and Human Services.

Dr. Krumholz reported that he chairs the scientific advisory board for United Healthcare.


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