Despite being widely used as measure for quality, mortality rates may be a misleading quality indicator because hospitals use varied accounting methods, according to a new study published in yesterday's Annals of Internal Medicine.
Researchers at Yale School of Medicine questioned two popular approaches to measuring quality--looking at patient deaths during their initial hospitalization and during a 30-day period, even after they leave the hospital, according to a Yale News brief. They found that quality can look very different when using the two accounting methods.
"We were concerned that only counting deaths during the initial hospitalization can be misleading," lead researcher Dr. Elizabeth Drye, research scientist at Yale School of Medicine's Center for Outcomes Research and Evaluation, said in the news brief. "Because some hospitals keep their patients for less time than others due to patient transfers to other facilities or because they send patients home more quickly."
Drye suggested that hospitals use a standard time period, such as 30 days.
The study calls into question the long-standing quality measure. For example, the Centers for Medicare & Medicaid Services (CMS) national database, Hospital Compare, as well as the popular "Best Hospitals" list from U.S. News & World Report, use patient mortalities to rate hospitals, compared against each other.
Previous studies also have found that mortality rates and hospital rankings are statistically imprecise and rather based on chance. In last year's Pediatrics study, half of confidence intervals overlapped at least 22 of the 42 possible ranking positions, meaning that if a hospital ranked number 15 on a list, it could have just as easily been named number 37.
Even more, another study in Circulation: Cardiovascular Quality and Outcomes last year suggested hospitals explore the various approaches to calculating composite scores and compare the conclusions that each composite score offers on the same set of performance measures.
To learn more:
- read the Yale News brief
- check out the study abstract
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