Hospital Visits after General Surgery Procedures Performed at Ambulatory Surgical Centers Measure Technical Report: Public Comment Submitted by: Yale New Haven Health Services Corporation – Center for Outcomes Research and Evaluation (CORE) Prepared for: Centers for Medicare & Medicaid Services (CMS) July 3, 2017 Table of Contents 1. List of Tables ............................................................................................................................ 4 2. List of Figures ........................................................................................................................... 5 3. Yale New Haven Health Services Corporation – Center for Outcomes Research and Evaluation (CORE) Project Team ..................................................................................................... 6 4. Acknowledgements.................................................................................................................. 7 5. Executive Summary .................................................................................................................. 9 5.1 Rationale for Assessing Hospital Visits after Ambulatory Surgery .................................... 9 5.2 Measure Development .................................................................................................... 10 5.3 Draft Measure Specifications........................................................................................... 10 5.4 Distribution of Measure Scores ....................................................................................... 11 5.5 Summary .......................................................................................................................... 11 6. Introduction and Call for Public Comment ............................................................................ 12 6.1 Background ...................................................................................................................... 12 6.2 Definition of an Ambulatory Surgical Center (ASC) ......................................................... 12 6.3 Importance of Assessing Unplanned Hospital Visits after ASC Procedures .................... 13 6.4 Related Measures Under Development .......................................................................... 14 7. Measure Development Methods ........................................................................................... 15 7.1 Overview of Measure Development Process .................................................................. 15 7.2 Data Sources .................................................................................................................... 15 7.3 Cohort Definition ............................................................................................................. 16 7.3.1 Inclusion Criteria ....................................................................................................... 16 7.3.2 Exclusion Criteria....................................................................................................... 18 7.4 Outcome .......................................................................................................................... 18 7.4.1 Definition of Outcome .............................................................................................. 18 7.4.2 Outcome Timeframe ................................................................................................. 18 7.4.3 Multiple Qualifying Procedures within a 7-Day Period ............................................ 18 7.4.4 All-Cause Hospital Visits ............................................................................................ 19 7.4.5 Removal of Planned Admissions from the Outcome ................................................ 19 7.5 Model Development ........................................................................................................ 20 7.5.1 Overview ................................................................................................................... 20 7.5.2 Candidate Risk Factors for Patient-Level Risk Adjustment ....................................... 21 7.5.3 Final Risk-Adjustment Variable Selection ................................................................. 22 7.5.4 Model Performance and Validation .......................................................................... 22 7.5.5 Selection of Random Effects Term Distribution ....................................................... 22 Hospital Visits after General Surgery ASC Procedures 2 7.5.6 Calculation of ASC-Level Measure Score Variation and Outlier Status .................... 23 7.5.7 ASC-Level Measure Score Reliability Testing ............................................................ 23 7.5.8 Statistical Software ................................................................................................... 23 8. Results .................................................................................................................................... 24 8.1 Cohort Size and Unadjusted Outcome Rates in the 2015 Data ....................................... 24 8.1.1 Cohort ....................................................................................................................... 24 8.1.2 Outcome Rates and Distribution .............................................................................. 24 8.2 Patient-Level Risk-Adjustment Model ............................................................................. 25 8.2.1 Candidate and Final Variables .................................................................................. 25 8.2.2 Model Performance and Validation .......................................................................... 25 8.3 ASC-Level Measure Score ................................................................................................ 25 8.3.1 ASC-Level Measure Score Variation and Outlier Status ........................................... 25 8.3.2 ASC-Level Measure Score Reliability Testing ............................................................ 26 9. Summary and Discussion ....................................................................................................... 27 10. References ............................................................................................................................ 28 11. Tables .................................................................................................................................... 31 12. Figures ................................................................................................................................... 53 13. Appendices ............................................................................................................................ 56 13.1 Appendix A: List of all CPT® Procedure Codes Included in the Measure Cohort .......... 56 13.2 Appendix B: Emergency Department Visits and Observation Stays Definition............. 74 13.3 Appendix C: Planned Admission Algorithm ................................................................... 74 13.4 Appendix D: Measure Score Calculation and Reporting ............................................... 91 13.5 Appendix E: Risk-Adjustment Model Development ...................................................... 93 Hospital Visits after General Surgery ASC Procedures 3 1. List of Tables Table 1. Frequency of risk model variables in the Medicare Development and Validation Samples (dataset: Medicare FFS CY 2015) ............................................................................ 31 Table 2. Top 20 procedures in the general surgery cohort (dataset: Medicare FFS CY 2015) ..... 32 Table 3. Number and frequency of emergency department visits, observation stays, and unplanned inpatient admissions (dataset: Medicare FFS CY 2015) ..................................... 33 Table 4. Top hospital visit diagnoses for any hospital visit within 7 days of general surgery procedures (dataset: Medicare FFS CY 2015) ....................................................................... 34 Table 5. Risk-adjustment model performance summaries in the Medicare Development and Validation Samples (dataset: Medicare FFS CY 2015) .......................................................... 50 Table 6. Model parameter estimates and odds ratios in the Medicare Development and Validation Samples (dataset: Medicare FFS CY 2015) .......................................................... 51 Table A1. List of included Current Procedural Terminology (CPT®) codes defining general surgery procedures (codes used to define the general surgery measure cohort) ............................ 56 Table B1. HCPCS codes or revenue center codes that define emergency department visits and observation stays .................................................................................................................. 74 Table PA1. Procedure categories that are always planned (Planned Readmission Algorithm Version 4.0 – adapted for General Surgery ASC Measure Version 1.0) ............................... 77 Table PA2. Diagnosis categories that are always planned (Planned Readmission Algorithm Version 4.0 – adapted for General Surgery ASC Measure Version 1.0) ............................... 77 Table PA3. Procedure categories that are potentially planned (Planned Readmission Algorithm Version 4.0 – adapted for General Surgery ASC Measure Version 1.0) ............................... 77 Table PA4. Diagnosis categories that