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August 17, 2005

Controlling for Patient Case Mix at the End of Life: Issues in Identifying Cause of Death

JAMA. 2005;294(7):791-794. doi:10.1001/jama.294.7.793-c

To the Editor: Researchers have used various methods to identify cause of death for case-mix classification at the end of life, but there has been no systematic evaluation of the consistency between these methods. The most common approach is to use the death certificate underlying cause of death, but the limitations of this method include problematic data quality,1 prohibitive cost of obtaining National Death Index data, and identification of the underlying cause of death (the condition that started the train of fatal events) may not be consistent with a particular research objective. Some researchers have used health care utilization data from their study data sets to identify cause of death for case-mix classification. The methods have included identifying the last major diagnosis (last-diagnosis method)2,3 and using the diagnosis responsible for the most resource use near death (cost method).4,5 We assessed the consistency among death certificate data and these 2 other methods.