As a measure of performance and quality, in-hospital mortality systematically favors hospitals with shorter length of stay (LOS) times, according to a new study published in Annals of Internal Medicine. The finding may have important implications for quality improvement initiatives that use mortality as a performance measure.
Elizabeth Drye and colleagues analyzed Medicare data from 3.5 million hospital admissions for acute MI, heart failure, and pneumonia. They observed wide variations in the LOS for each condition and large differences between the in-hospital and 30-day mortality rates. Performance ratings were different for a substantial number of hospitals based on the mortality assessment used.
- Mean LOS varied from 2.3 to 13.7 days
- In-hospital mortality and 30 day mortality: 10.8% and 16.1%
- 8.2% of hospitals had a change in performance classification based on type of mortality assessment
- Mean LOS varied from 3.5 to 11.9 days
- In-hospital mortality and 30 day mortality: 5.2% and 11.2%
- 10.8% of hospitals had a change in performance classification based on type of mortality assessment
- Mean LOS varied from 3.8 to 14.8 days
- In-hospital mortality and 30 day mortality: 6.4% and 12.2%
- 14.7% of hospitals had a change in performance classification based on type of mortality assessment
The authors concluded:
As the United States increases its use of outcome measures to assess and reimburse for quality and to evaluate system innovations, outcomes measures with standardized follow-up periods, which are unaffected by variation in LOS or transfer patterns, should be preferred over in-hospital measures. Building national databases of key outcomes that can be readily linked to patient data, such as mortality, would make measures that use standardized outcome periods more feasible and timely.