Prospective Payment System Evaluation Studies: PPS Impact on Mortality Rates. Adjustments for Case-Mix Severity

摘要

The purpose of the study was to evaluate the impact of the Prospective Payment System (PPS) on hospital quality of care by assessing changes in mortality rates between fiscal years 1984 and 1985, while adjusting for differential case-mix severity in the two years. The study thus had two objectives. The first was to develop a patient classification system in which patient categories are homogeneous on risk of mortality. The second was to use the system to adjust and compare mortality rates in 1984 and 1985 so as to evaluate the impact of PPS. Methods of indirect standardization were used to derive a 1985 expected overall mortality rate based on 1984 mortality rates per severity level. Comparisons were then made between the expected (severity adjusted) mortality rate and the observed mortality rate for 1985 as an assessment of PPS impact. The remaining sections of the report present the study in detail.