Heart attack death rates appear lower at 'America's best hospitals'

Jul 10 2007

Individuals admitted for heart attack to a hospital ranked as one of America's Best by U.S. News & World Report are less likely to die within 30 days than those admitted to a non-ranked hospital, according to a report in the July 9 issue of Archives of Internal Medicine.

Using a methodology that is similar to the recently released mortality measures that are publicly reported by the Centers for Medicare and Medicaid Services (CMS), the study found that ranked hospitals were also more likely to have lower-than-expected death rates however, many unranked hospitals did as well.

"Among the increasing number of academic, industry and governmental profiling systems that evaluate and compare hospitals, U.S. News & World Report's annual issue of America's Best Hospitals for specialty and overall care is one of the most well known," the authors write as background information in the article. "Despite their prominent role in the public arena, the ability of the U.S. News & World Report rankings to identify hospitals with excellent survival rates for common cardiovascular conditions is not known."

Oliver J. Wang, M.D., of Yale University School of Medicine, New Haven, Conn., and colleagues assessed 30-day death rates among 13,662 patients admitted to 50 hospitals ranked on the U.S. News list as the best in Heart and Heart Surgery and among 254,907 patients admitted to 3,813 unranked hospitals in 2003. The researchers also compared the hospitals standardized mortality ratios, where a ratio of greater than one indicates that the hospital had more deaths than expected and a ratio of less than one means there were fewer deaths than expected.

After the researchers factored in patient characteristics, the 30-day death rates were, on average, lower in ranked hospitals vs. non-ranked hospitals (16 percent vs. 17.9 percent). When the hospitals were divided into four groups based on these rates, 35 ranked hospitals (70 percent) were in the group with the fewest deaths, 11 (22 percent) were in the middle two groups and four (8 percent) were in the worst-performing group.

Eleven ranked hospitals (22 percent) and 28 non-ranked hospitals (0.73 percent) had standardized mortality ratios significantly less than one, meaning that although ranked hospitals were more likely to have lower-than-expected death rates, non-ranked hospitals with favorable ratios outnumbered ranked hospitals with similar performance by nearly three to one. "As a result, the U.S. News & World Report ranking list does not include many hospitals that have outstanding performances for the care of patients with acute myocardial infarction," or heart attack, the authors write.

One reason for this may be the reputation component of the rankings, which accounts for one-third of the overall ranking score and is based on cardiologists opinions of hospitals that provide the best treatment, the authors speculate. "Citations by cardiologists likely favor tertiary centers with strong subspecialty care for the most critically ill patients while not necessarily reflecting the perceived care for the overwhelming majority of admissions for more common diagnoses, which in turn have a more substantial impact on overall hospital outcomes," they continue.

"The U.S. News & World Report ranking, which includes many of the nation's most prestigious hospitals, did identify a group of hospitals that was much more likely than non-ranked hospitals to have superb performance on 30-day mortality after acute myocardial infarction," the authors conclude. "However, our study also revealed that not all ranked hospitals had outstanding performance and that many non-ranked hospitals performed well. Consequently, although the U.S. News & World Report rankings provide some guidance about the performance on outcomes, they fall short of identifying all the top hospitals with respect to 30-day survival after admission for acute myocardial infarction and include a few hospitals that are actually in the lowest quartile of performance."

Although hospital rankings are now published by a wide variety of governmental and non-governmental organizations, it is unclear how useful they are to patients, write Sean Michael O'Brien, Ph.D., and Eric D. Peterson, M.D., of Duke University, Durham, N.C, in an accompanying editorial.

"A growing literature of methodological studies presents a sobering picture for patients who would like to use available quality information to identify hospitals with the best outcomes for a particular condition," they write. "Most systems seem to do a reasonable job at identifying groups of hospitals that perform well on average, yet there is considerable uncertainty regarding the true performance of a particular hospital. As noted, some truly exceptional hospitals will be improperly rated as poor whereas some mediocre hospitals will be rated as excellent."

However, that does not mean that assessing hospital quality has no role in medicine, they write. Hospitals ranked poorly should take action, and those ranked highly should not boast or become complacent. "They need to understand the potential inconsistency and fallibility of quality-ranking systems. And they need to realize that regardless of their true rank, their goal should not be to merely beat their peers in the ratings but to strive for optimum performance. In this type of quality competition, the real winners are the patients," Drs. O'Brien and Peterson conclude.

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