A Matter of Life or Death
“Mortality Ratios” are quality data that compare patients’ actual mortality rates to their expected mortality rates, based on patients’ severity of illness. This takes into account all their medical problems and the severity of those problems. In the case of mortality rates, lower is better. A lower score mortality ratio means that more patients survived than were expected due to the severity of their illnesses. The specific measure is called a “risk adjusted mortality ratio.”
Risk Adjusted Mortality Ratio = Observed mortality/Expected mortality
Observed mortality is the actual number of inpatient deaths that occur in the hospital during a specific period.
Expected mortality is the predicted number of deaths in the hospital based on the patients’ levels of illness at the hospital. Patients who are very sick (higher severity of illness) have a higher expected mortality rate.
A mortality ratio of 1.0 means the observed mortality equals the expected mortality for this patient population. A ratio of less than 1.0 means that fewer patients died than expected based on the performance of other hospitals as adjusted for patients with the same types and severity of medical problems.