A description and clinical assessment of the Computerized Severity Index.

Recent initiatives expanding health care data networks have increasingly emphasized severity of illness information, both to improve fairness of hospital payment and to assist in widespread assessment of hospital and physician quality. The Computerized Severity Index (CSI), one of the newest severity tools to generate interest, is disease specific and produces scores from 1 to 4 at both the disease and overall patient levels. Severity is defined as "the treatment difficulty presented to physicians due to the extent and interactions of patient's diseases." The clinical logic of the severity rating system is readily available through the "severity matrices" associated with over 820 disease groups. Questions exist about the CSI's dependence on diagnostic coding and the qualitative nature of some of the clinical criteria. More study is required to assess the utility of the CSI for various health policy purposes.