CARDIAC CARE: METHODOLOGY
Through partnership and under contract with Ramesh K. Shukla, Ph.D., Professor at the Williamson Institute at Virginia Commonwealth University's Department of Health Professions, VHIs goal has been to develop information that fairly compares hospitals' performance, mortality and readmission outcomes. Dr. Shukla directed the scientific research in developing a reliable and valid methodology for the cardiac care information. Because some patients may have more serious conditions or require more complicated treatment than others, it was very important to VHI to develop a methodology that adjusts for these differences in patient severity of illness and risk of mortality. After adjustments have been made to the data, it is clear that some hospitals seem to have lower rates of mortality or readmissions than others.
DATA COLLECTION AND SCREENS
VHI tested mortality rate outcomes on an APR-DRG level. Most commonly, an APR-DRG was automatically excluded due to too few or no mortality cases being reported. Other APR-DRGs did not pass additional statistical tests. Overall, about 75% of the APR-DRGs had sufficient cases and passed the statistical tests. The decision was made to exclude those APR-DRGs not passing criteria in mortality rate calculations. All APR-DRGs in some service lines did not pass the statistical tests and are, therefore, not to be reported.
To ensure that the methodology was as sensitive as possible to variations in patient outcomes by clinical condition, VHI made a decision to focus on a limited number of service lines. Cardiac Care discharges were chosen because they occur frequently. As a group they are the largest category of discharges after normal newborns/obstetrics and represent over 12% of Virginia discharges. Analysis also noted that most hospitals treat patients needing Cardiac Care, and preliminary analysis indicated that the APR-DRG adjustment methodology was explaining a high degree of variation among discharges.
Development of these reports began with Virginia hospital discharges in calendar year 2000. Detailed statistical analysis and review followed to help identify variables outside the control of hospitals that might affect mortality outcomes. In 2006 a cardiac care expert panel provided provided input on the adjustment methodology and recommended adoption of using version 20.0 of 3M's APR-DRGs and a methodology for identifying 30-day related readmissions.
The following additional adjustments were first applied to 2004 discharges for publication in September 2006:
1. Discharges are removed when the discharge is identified as a hospice/palliative care patient (identified by either primary or secondary diagnosis code of V66.7, discharge status codes of 50 or 51 or revenue codes indicating hospice care).
2. All discharges are removed if they contained an admission source code indicating they were transferred in from another hospital (ASCRE = 4), and their condition reflected a Severe Risk of Mortality (ROM 4), and a discharge disposition of expired (discharge status equals 20) was reported and the calculated length of stay was equal to one day or less.
3. Discharges are removed if a discharge disposition indicating they were transferred to another short term acute care or federal hospital (Patient Status = 2 or 43).
4. APR-DRGs that did not pass initial testing for volume and reliability.
5. The decision was made not to report information by hospitals with less than 30 cases in a particular service line.
A FRAMEWORK FOR OUTCOMES ASSESSMENT
VHI collected data from all of the hospitals in the state of Virginia for Cardiac Care and then ran statistical tests to determine the validity of the 3M APR-DRG system for classification and analysis of clinical risk assessment. The tests were run using SPSS statistical analysis software under the direction of Ramesh K. Shukla, Ph.D, of the Williamson Institute. Tests included analysis of face validity, paired correlations, and quantitative analysis of confidence intervals. After working through these statistical techniques for the three service lines, the methodology was adopted.
INDICATORS OF CLINICAL ASSESSMENT
When a doctor evaluates a patient, a wide variety of information may be used to make a diagnosis and recommend care that is needed. These indicators of condition may include age, gender, current illnesses, family history, the results of blood and other tests and other information that the doctor obtains. The information VHI uses was derived in part from the findings of hospital care and includes the age of a patient as well as the gender, diagnoses, and diagnostic and surgical procedures performed. All these factors are considered when VHI compares hospitals based on their patients.
For a more technical review of APR-DRG assessment, please click here to view the section VALIDATING APR-DRGs FOR CARDIAC CARE.
Click here to view a step-by-step example of how mortality is calculated.
Click here to view a step-by-step example of how related readmissions are calculated.