Study finds variability in measurement of hospital-wide mortality rates

Four common methods for calculating hospital-level mortality produced substantially different results in a study reported recently in the New England Journal of Medicine, writes AHA News. Although the four methods used identical information on discharges from Massachusetts acute-care hospitals between October 2004 and 2007, they produced different estimates of hospital-level mortality and assessments of whether individual hospitals had higher-than-expected or lower-than-expected mortality. “The four commercially available methods for assessing hospital-wide mortality that we studied are marketed to hospitals to support internal quality-improvement activities,” the authors state. “However, their implications are even more important, and the corresponding need for methodologic accuracy is greater, when such measures are used for broader initiatives, such as public reporting or performance-based purchasing. We found that estimates of hospital-wide mortality could vary, sometimes widely, among methods, which consequently leads to different inferences regarding the quality of hospital care. Although these analyses used Massachusetts data, our results should be generalizable to other hospitalized populations.”