The measurement of mortality. A risk-adjusted variable time window approach.

This paper describes the development of risk-adjusted mortality indices (RAMI) using 1985 MEDPAR data from 657 hospitals. The RAMI methodology is adopted from the Commission on Professional and Hospital Activities, however, both inhospital and post-discharge deaths are counted within time windows that vary by clinical condition. Five different RAMI measures (expected deaths/observed deaths) are developed, compared, and aggregated into various hospital characteristic strata. These measures vary by which discharge is held responsible for deaths within a time window, and whether or not inhospital deaths that occur beyond the time window are included. The RAMIs using varying time windows are compared with the RAMIs based upon inhospital deaths only. The inhospital RAMI was higher for the nonteaching hospitals (.95) as compared with the major and minor teaching institutions (.91 and .89). The RAMIs using the varying time windows, on the other hand, tend to be higher for the teaching institutions (e.g., 1.07 for major teaching hospitals; 0.99 for nonteaching hospitals).

Measuring hospital performance. The development and validation of risk-adjusted indexes of mortality, readmissions, and complications.

In this study we used information from discharge abstracts to develop three different risk-adjusted measures of hospital performance: a Risk-Adjusted Mortality Index, a Risk-Adjusted Readmissions Index, and a Risk-Adjusted Complications Index. The adjustments have face validity, and appear to account for much of the variation across hospitals in the rates of these adverse events. The indexes are stable over time, and are not biased with respect to hospital size, ownership, or teaching status. All three indexes appear to have construct validity when tested against the changes in hospital care that occurred when PPS was introduced.

The Risk-Adjusted Mortality Index. A new measure of hospital performance.

The Commission on Professional and Hospital Activities (CPHA) developed the Risk-Adjusted Mortality Index (RAMI), a method for comparing hospital death rates using existing abstract or billing data. The method is comprehensive insofar as it includes all payers and all types of cases except neonates. RAMI was designed to differentiate among admissions on the basis of the patient characteristics that increase or reduce the risk of dying in the hospital. Using a large national data base, risk factors were determined empirically within each of 310 clusters based on diagnosis-related groups (DRGs). The model was very effective at predicting risk-adjusted outcomes, with a correlation of 0.98 between actual and predicted deaths in a sample of 300 hospitals. RAMI appears to be a powerful tool for using existing data to monitor changes over time in hospital death rates.