The Limited Utility of Ranking Hospitals Based on Their Colon Surgery Infection Rates

• Published in: Clinical infectious diseases 2021-01, Vol.72 (1), p.90-98
• Main Authors: Caroff, Daniel A, Wang, Rui, Zhang, Zilu, Wolf, Robert, Septimus, Ed, Harris, Anthony D, Jackson, Sarah S, Poland, Russell E, Hickok, Jason, Huang, Susan S, Platt, Richard
• Format: Article
• Language: English
• Subjects: Adult; Aged; and Commentaries; Colon - surgery; Digestive System Surgical Procedures; Hospitals; Humans; Medicare; Retrospective Studies; Surgical Wound Infection - epidemiology; United States - epidemiology
• ISSN: 1058-4838; 1537-6591
• DOI: 10.1093/cid/ciaa012

Abstract Background The Centers for Medicare and Medicaid Services (CMS) use colon surgical site infection (SSI) rates to rank hospitals and apply financial penalties. The CMS’ risk-adjustment model omits potentially impactful variables that might disadvantage hospitals with complex surgical populations. Methods We analyzed adult patients who underwent colon surgery within facilities associated with HCA Healthcare from 2014 to 2016. SSIs were identified from National Health Safety Network (NHSN) reporting. We trained and validated 3 SSI prediction models, using (1) current CMS model variables, including hospital-specific random effects (HCA-adapted CMS model); (2) demographics and claims-based comorbidities (expanded-claims model); and (3) demographics, claims-based comorbidities, and NHSN variables (claims-plus–electronic health record [EHR] model). Discrimination, calibration, and resulting rankings were compared among all models and the current CMS model with published coefficient values. Results We identified 39 468 colon surgeries in 149 hospitals, resulting in 1216 (3.1%) SSIs. Compared to the HCA-adapted CMS model, the expanded-claims model had similar performance (c-statistic, 0.65 vs 0.67, respectively), while the claims-plus-EHR model was more accurate (c-statistic, 0.70; 95% confidence interval, .67–.73; P = .004). The sampling variation, due to the low surgical volume and small number of infections, contributed 74% of the total variation in observed SSI rates between hospitals. When CMS model rankings were compared to those from the expanded-claims and claims-plus-EHR models, 18 (15%) and 26 (22%) hospitals changed quartiles, respectively, and 10 (8.3%) and 12 (10%) hospitals changed into or out of the lowest-performing quartile, respectively. Conclusions An expanded set of variables improved colon SSI risk predictions and quartile assignments, but low procedure volumes and SSI events remain a barrier to effectively comparing hospitals. Using additional variables can improve risk adjustments of hospital-level colon surgical site infection rates, but have limited impact on financial penalties. Low procedure and infection rates contribute to much of the between-hospital variation.