ICU Discharge Policies May Bias Hospital Quality Measurement

A new study suggests that while in-hospital mortality for intensive care unit (ICU) patients is often used as a quality measure, discharge practices may bias the results in a way that disadvantages large academic hospitals.

Researchers at the University of Pittsburgh School of Medicine (PA, USA) conducted a retrospective cohort study using data on 43,830 ICU patients admitted to 134 hospitals in the state of Pennsylvania in 2008. Discharge bias was defined as 30-day ICU mortality minus in-hospital mortality. The results showed that the mean risk-adjusted hospital-specific 30-day and in-hospital mortality rates were 13.1% and 9.6%, respectively, resulting in a mean hospital-specific discharge bias of 3.5%. Discharge bias was greater in small hospitals, nonteaching hospitals, and hospitals with fewer commercial health maintenance organization (HMO) patients.

The discharge bias resulted in these facilities appearing relatively better in quality compared to large teaching hospitals, or those with a high proportion of commercial HMO patients. Hospital rank was also greatly affected by discharge bias, with 29.1% of hospitals increasing in rank by at least one quartile and 26.9% decreasing in rank by at least one quartile. Large teaching hospitals and hospitals with the highest proportion of HMO patients were more likely to decrease in rank than small, nonteaching hospitals or hospitals with a lower proportion of HMO patients. The study was presented at the American Thoracic Society 2012 International Conference, held during May 2012 in San Francisco (CA, USA).

“Mortality measures tied to a specific time point, such as 30-day mortality, are less biased by discharge practices, but are harder to calculate,” said lead author and study presenter Lora Reineck, MD. “State and national programs that use in-hospital mortality to benchmark hospitals should note how discharge bias unfairly disadvantages certain types of hospitals; accounting for this bias might prevent these hospitals from being unfairly penalized in public reporting or pay-for-performance programs.”

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University of Pittsburgh School of Medicine