Presented by: Hannah Kay MD
University of North Carolina at Chapel Hill

Introduction

Central to United States (US) efforts to reduce healthcare spending are alternative payment models (APMs) that seek to link provider incentives to performance measurements/the cost of care. Surgical APMs largely consist of bundled payments, whereby providers are given a lumpsum payment for a single surgical episode and all related care over a pre-specified time period. However, debate exists over how to accurately define the time horizon of a surgical episode of care.  We use renal colic as a model surgical condition to validate a novel claims-based approach to defining surgical episodes of care more broadly.

Materials

We queried the 2015-2020 Carolina Cost and Quality Initiative claims dataset to identify patients presenting to an emergency department (ED) with a primary diagnosis of renal colic. Clinical and sociodemographic data was collected as were weekly charges stratified by surgery status in the 13 weeks preceding and following the initial ED encounter. Non-parametric bootstrapping was performed to calculate changes in mean weekly charges and their accompanying 95% confidence intervals (CI).  An episode was defined as the period of time where the 95% CIs for the change in mean weekly charges did not contain a zero value.

Results

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We identified 34,515 individuals experiencing 38,196 index renal colic episodes over the study period. Males comprised 53.1% of the cohort, while the median age at time of the index encounter was 46.0 years (IQR 36.0-55.0 years). 19.0% (n=6,566) of individuals subsequently underwent definitive surgery within 90 days, with median time to surgery being 8 days (IQR 2-36 days). Procedures performed included ureteroscopy (14.7%) followed by shockwave lithotripsy (4.2%), and percutaneous nephrolithotomy (0.3%).  Average episode duration was 6 weeks for individuals not requiring surgery compared to 12 weeks for those requiring surgery.

Conclusion

To our knowledge this is the first study to use a claims-based approach to defining an episode of renal colic.  We show that episodes requiring surgery are twice as long as those that don’t require surgery, and that episode onset precedes the index ED visit by 2 weeks.  Our findings have important implications for ongoing APM reforms taking place in the US.

Funding

American Urological Association Research Scholars Grant

Lead Authors

Matthew E. Nielsen, MD, MS, FACS
University of North Carolina at Chapel Hill

Charles D. Scales, MD, MSHS, FACS
Duke University

David F. Friedlander, MD, MPH
University of North Carolina at Chapel Hill