Risk Stratification for Congenital Heart Surgery for ICD-10 Administrative Data (RACHS-2)

the New York State CHS-COLOUR

Research output: Contribution to journalArticlepeer-review


Background: As the cardiac community strives to improve outcomes, accurate methods of risk stratification are imperative. Since adoption of International Classification of Disease-10th Revision (ICD-10) in 2015, there is no published method for congenital heart surgery risk stratification for administrative data. Objectives: This study sought to develop an empirically derived, publicly available Risk Stratification for Congenital Heart Surgery (RACHS-2) tool for ICD-10 administrative data. Methods: The RACHS-2 stratification system was iteratively and empirically refined in a training dataset of Pediatric Health Information Systems claims to optimize sensitivity and specificity compared with corresponding locally held Society of Thoracic Surgeons-Congenital Heart Surgery (STS-CHS) clinical registry data. The tool was validated in a second administrative data source: New York State Medicaid claims. Logistic regression was used to compare the ability of RACHS-2 in administrative data to predict operative mortality vs STAT Mortality Categories in registry data. Results: The RACHS-2 system captured 99.6% of total congenital heart surgery registry cases, with 1.0% false positives. RACHS-2 predicted operative mortality in both training and validation administrative datasets similarly to STAT Mortality Categories in registry data. C-statistics for models for operative mortality in training and validation administrative datasets—adjusted for RACHS-2—were 0.76 and 0.84 (95% CI: 0.72-0.80 and 0.80-0.89); C-statistics for models for operative mortality—adjusted for STAT Mortality Categories—in corresponding clinical registry data were 0.75 and 0.84 (95% CI: 0.71-0.79 and 0.79-0.89). Conclusions: RACHS-2 is a risk stratification system for pediatric cardiac surgery for ICD-10 administrative data, validated in 2 administrative–registry-linked datasets. Statistical code is publicly available upon request.

Original languageEnglish (US)
Pages (from-to)465-478
Number of pages14
JournalJournal of the American College of Cardiology
Issue number5
StatePublished - Feb 8 2022


  • ICD-10
  • New York Congenital Heart Surgeons Collaborative for Longitudinal Outcomes and Utilization of Resources
  • RACHS-1
  • RACHS-2
  • administrative data
  • congenital heart surgery
  • mortality
  • outcomes
  • risk adjustment
  • risk stratification

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine


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