The Severity of Illness Index as a severity adjustment to diagnosis-related groups.
Bottom Line: Comparative analyses of the resulting case-mix groups within hospitals, and an application of severity-adjusted diagnosis-related groups case-mix definitions.Cross-hospital comparisons.Some of the consequences of incorporating a patient severity refinement into the prospective payment system.
This article discusses the Severity of Illness case-mix groups, and suggests a refinement to diagnosis-related groups (DRG's) designed to accommodate the important element of patient severity. An application of the suggested refinement is presented in a discussion of the efficient production of hospital services. The following areas are addressed. A brief summary of the goals and development of the Severity of Illness Index, and the methodology used to collect severity of illness data on hospital inpatients. Comparative analyses of the resulting case-mix groups within hospitals, and an application of severity-adjusted diagnosis-related groups case-mix definitions. The contribution of the variation in physician practice patterns to the variation in resource use per patient within a hospital. Cross-hospital comparisons. Some of the consequences of incorporating a patient severity refinement into the prospective payment system.
Mentions: If a hospital's (or a physician's) resource use within a DRG is higher than a typical level, it could be that the institution (or physician) is inefficient. It could also mean that the institution or physician is treating patients who are more severely ill. Because severity-adjusted DRG's produced the most homogeneous groups in this study, patients from the whole institution were placed into the appropriate DRG group and further subclassified by severity of illness level and procedure type (DRG, severity, procedure). As the norms of practice in each institution, we used the average resource use expressed in terms of total charges, length of stay, laboratory charges, radiology charges, routine charges, and pharmacy charges for patients in each DRG, severity, procedure group. Subsequently, we compared the resource use of each physician's patients with the norms in the appropriate categories. For each physician, we then accumulated the differences between each of his patient's resource use and the norms, controlling for DRG, severity, and procedure type. The results are explained in more detail in another article (Horn, Horn, and Moses, 1984). It was found that some physicians treated most of their patients with less resource use than the norms, and some with more. The same comparisons were also made when the patients were grouped only by DRG's, and not adjusted for severity or procedure type (Figure 8). The two different methods of assessing an individual physician's efficiency often led to different conclusions. These disparate results signal to a hospital administrator that the underlying causes of the differences should be investigated. Only a more detailed review will show whether the differences are because of quality of care, efficiency, or treatment of more severe cases. However, the implications of these differences between DRG's and severity- and procedure-adjusted DRG's are great. Where will medical practice be in the future if the wrong physicians are criticized (or praised) for atypical practice patterns?