Surgeon- and Hospital-Level Contributions to Surgical Supply Cost Variation in an Integrated Health System

Direct surgical supply costs are a modifiable component of operating room spending, but it is unclear whether variation reflects reproducible hospital- and surgeon-level practice patterns and whether stewardship opportunity is broadly distributed or concentrated.

Retrospective observational study of 298,723 operative encounters from April 1, 2019, to March 31, 2025, across 15 hospitals in a single integrated health system. Hierarchical mixed-effects linear regression modeled log supply cost per case with random intercepts for hospitals and surgeons nested within hospitals, adjusting for CPT3 procedural family, calendar year, COVID-era indicator, and, in a complete-case subset, operative duration. Modeled excess cost benchmarked adjusted supply costs to internally observed top-quartile performance within each CPT3 family.

In the baseline model (n = 298,723), hospital-level factors accounted for 35.4% and surgeon-within-hospital factors for 32.7% of total variance (cumulative intraclass correlation coefficient [ICC], 0.681). After operative time adjustment (n = 150,461), hospital variance was 38.1% and surgeon-within-hospital variance was 26.9% (cumulative ICC, 0.650). Benchmarking corresponded to a 20-25% reduction in mean supply cost per case, with approximately 62% persisting after time adjustment. Fewer than 15% of CPT3 families accounted for more than half of modeled opportunity, and the top 5% of surgeons accounted for 56.1% of modeled excess cost. Higher adjusted supply costs were not consistently associated with 30-day readmission (adjusted odds ratio per 1-SD increase, 1.03; 95% CI 0.97-1.09).

Surgical supply cost variation was reproducible, concentrated, and only partly explained by operative duration. These findings support targeted supply stewardship focused on high-impact procedure families and surgeons.