Significant improvements in short-term acute-MI mortality in US hospitals

Thursday, August 20, 2009

by Michael O'Riordan

New Haven, CT - In the past decade, 30-day mortality rates for patients discharged with acute MI have significantly declined, as has the variation in AMI mortality in hospitals across the US, a new study has shown [1]. Overall, the 30-day mortality rates declined from 18.8% in 1995 to 15.8% in 2006, an approximate one-sixth reduction in short-term mortality over the 12-year study period, report investigators.

"A challenge was really set down about a decade ago, where we really needed to achieve a better system and wanted to shift the entire spectrum of performance toward better care," said lead investigator Dr Harlan Krumholz (Yale University School of Medicine, New Haven, CT). "That meant that we weren't really looking at the outliers but saying that the status quo is not acceptable. This paper is showing the realization of what we hoped to accomplish, which is a shift in the distribution of mortality, and the variation shrinking. We've improved performance and shrunk some of that variation between hospitals."

The results of the study are published in the August 19, 2009 issue of the Journal of the American Medical Association.

Plans made 10 years ago

Speaking with heartwire, Krumholz said that while there is some surveillance and patient-level data looking at AMI outcomes, there wasn't a systematic look at outcomes at the hospital level in the US. Also, during the early 1990s, much of the research was focused on outliers and "trying to figure out if there was a bad apple, someone that was practicing in a way that might be harmful or at odds with how everybody else was practicing," he said.

Now, however, much of the focus has been to improve the entire system by measuring and improving care at all hospitals, and not just those performing poorly, added Krumholz. This focus has included interventions and efforts toward improving quality of care as they relate to clinical guidelines and performance measures.

In this study, the researchers examined hospital-level 30-day risk-standardized mortality rates by obtaining data from the Centers for Medicare and Medicaid Services (CMS) analysis and review files. Between 1995 and 2006, there were more than three million hospital discharges of patients 65 years of age and older from acute-care hospitals in the US.

As noted, there was a reduction in hospital-specific 30-day all-cause mortality. According to the researchers, for every 33 patients admitted in 2006 for an AMI compared with 1995, there was additional patient alive at 30 days.

All-cause mortality from 1995 to 2006

30-day risk standardized all-cause mortality rate (range)
18.8 (10.4-27.5)
18.2 (9.1-26.7)
17.7 (9.0-26.5)
17.8 (12.3-25.3)
19.3 (14.4-25.4)
18.8 (12.9-27.0)
18.5 (13.1-26.1)
17.9 (13.1-25.0)
17.6 (12.1-24.1)
17.0 (12.3-22.9)
16.5 (11.0-24.8)
15.8 (14.7-16.8)

The group also observed a reduction of between-hospital heterogeneity in mortality. Nationally, the largest absolute reduction in AMI mortality was observed in the South, specifically the West-South-Central region, while the Pacific region had the smallest improvements.

Krumholz told heartwire that hospitals that would have been considered "average" in 1995 would be considered poor performers in 2006 if they didn't improve over time.

"They would have been left behind," he said. "It really shows the importance of continual improvement and not being complacent with the status quo, especially if you're considered average, because if we're doing things right we're really pushing the curve toward getting better. The fact is that, even now, we still see this distribution where there is still room for improvement. If we can take the bottom 75% and push them toward the performance of the top 25%, then we can still save a lot more lives."

Krumholz noted that Dr Eugene Braunwald (Harvard Medical School, Boston, MA) identified in 1997 two eras of innovation that reduced mortality for patients with AMI, the first being the introduction of cardiac units and defibrillation in the 1960s, and the second being interventional and pharmacologic strategies. Since then, the increased focus on systems and ensuring that people are adhering to quality-improvement measures has also helped reduce the hospital-specific AMI mortality rates, he said.


  1. Krumholz HK, Wang Y, Chen J, et al. Reduction in acute myocardial infarction mortality in the United States. JAMA 2009; 302:767-773.


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