Assessment of a University of California, Los Angeles 4-variable risk score for advanced heart failure
Ulrik Sartipy1, Ayumi Goda2, Donna M Mancini3
1Department of Cardiothoracic Surgery and Anesthesiology, Karolinska University Hospital, Stockholm, Sweden (U.S.) Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden (U.S.).
Insights
The UCLA risk score for advanced heart failure needs further assessment. External validation showed inconsistent calibration and poor discrimination in high-risk patients, questioning its use for heart transplantation or LVAD selection.
Area of Science:
- Cardiology
- Medical Statistics
Background:
- The University of California, Los Angeles (UCLA) 4-variable risk score showed promise in advanced heart failure.
- External validation and suitability for heart transplantation (HT) and left ventricular assist device (LVAD) selection were previously unknown.
Purpose of the Study:
- To externally validate the UCLA 4-variable risk score.
- To assess its utility in predicting outcomes for patients referred for HT.
Main Methods:
- Calculated the UCLA risk score (BNP, peak VO2, NYHA class, ACEI/ARB use) in 180 patients.
- Assessed survival free from urgent HT or LVAD.
- Compared model-predicted survival with Kaplan-Meier estimates.
- Evaluated model discrimination and calibration.
Main Results:
- 37 events (21%) occurred during a mean 2.1-year follow-up.
- Observed 1-, 2-, and 3-year event-free survival was 88%, 81%, and 75%.
- Model discrimination was good overall (AUCs 0.801-0.837) but poor between the highest risk groups.
- Model calibration was inconsistent, with observed/predicted ratios ranging from -14 to +17 percentage points.
Conclusions:
- The UCLA 4-variable risk model demonstrated inconsistent calibration and poor discrimination in high-risk groups during external validation.
- Further assessment is required before widespread clinical adoption for HT or LVAD selection.
Background:
The 4-variable risk score from University of California, Los Angeles (UCLA) demonstrated superior discrimination in advanced heart failure, compared to established risk scores. However, the model has not been externally validated, and its suitability as a selection tool for heart transplantation (HT) and left ventricular assist device (LVAD) is unknown.
Methods And Results:
We calculated the UCLA risk score (based on B-type natriuretic peptide, peak VO2, New York Heart Association class, and use of angiotensin-converting enzyme inhibitor or angiotensin receptor blocker) in 180 patients referred for HT. The outcome was survival free from urgent transplantation or LVAD. The model-predicted survival was compared to Kaplan-Meier's estimated survival at 1, 2, and 3 years. Model discrimination and calibration were assessed. During a mean follow-up of 2.1 years, 37 (21%) events occurred. One-, 2- and 3-year observed event-free survival was 88%, 81%, and 75%, and the observed/predicted ratio was 0.97, 0.96, and 0.97, respectively. Time-dependent receiver operating characteristic curve analyses demonstrated good discrimination overall (1-year area under curve, 0.801; 2-year, 0.774; 3-year, 0.837), but discrimination between the 2 highest risk groups was poor. The difference between observed and predicted survival ranged from -14 to +17 percentage points, suggesting poor model calibration. Fairly similar results were found when the analyses were repeated in 715 patients after multivariate imputation of missing data.
Conclusions:
The UCLA 4-variable risk model calibration was inconsistent and high-risk discrimination was poor in an external validation cohort. Further model assessment is warranted before widespread use.
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