V. C. Nikolian1, N. Kamdar1, I. S. Dennahy1, S. Hendren1, D. S. Campbell1, P. Suwanabol1 1University Of Michigan Health System,General Surgery,Ann Arbor, MI, USA
Introduction: Geriatric-specific morbidity and mortality are known to increase with frailty. Indices have been developed to predict outcomes in this population, yet it is unclear whether worse outcomes are unavoidable and related to patient factors, or modifiable and influenced by hospital factors. A paucity of data exists comparing outcomes between hospitals for frail patients undergoing colorectal surgery. Using data abstracted from medical records in a statewide surgical collaborative, we sought to determine whether risk-adjusted outcomes related to reoperations, readmissions, and mortality varied between hospitals.
Methods: Patients ≥ 65 years old who underwent colon and rectal resections in the Michigan Surgical Quality Collaborative (MSQC) from July 2012 – June 2015 were identified. Using a previously published frailty-based surgical risk model, frailty scores were calculated by adding the components of albumin <3.4 g/dL, hematocrit <35%, serum creatinine >2 mg/dL, and ASA score >3. Bivariate analysis was conducted to determine the mean unadjusted outcome rates for each value of the frailty score. Multivariable logistic regression models were developed with frailty score and other adjustment variables as covariates in order to determine risk-adjusted outcome rates for reoperations, readmissions, and mortality. Predicted probabilities and mean unadjusted frailty scores for each hospital were calculated. Using this method, outliers were identified by comparing the MSQC adjusted outcome rates with the 95% confidence interval (CI) of each hospital. Spearman rank correlation coefficients were calculated to determine the association between hospital unadjusted frailty scores and risk adjusted outcome rates.
Results: Of 3594 colorectal resections performed in 64 Michigan hospitals, the unadjusted reoperation, readmission, and mortality rates were 9.5%, 12.2%, and 6.1%, respectively. After controlling for urgent and emergent cases, age, race, operative time, BMI, male sex, medical school affiliation, and hospital size, multivariable analysis demonstrated that outcomes were significantly worse for the most frail patients. Odds ratios of developing complications in these patients were calculated relative to those with a frailty index of 0 (ORs: reoperation: 2.54, 95% CI: 1.2-5.5; readmission: 2.5, 95 CI = 1.2-5.3; mortality: 38.4, 95% CI 8.4-175.7). There was a high degree of correlation between hospital mean frailty scores and hospital-adjusted rates of reoperations, readmissions, and mortality (Spearman rank correlation for: reoperations = 0.81, readmissions = 0.713, mortality = 0.843; p < 0.0001). Using this methodology, outliers related to each outcome were identified.
Conclusion: Significant variation in postoperative outcomes exists between hospitals caring for frail patients. This suggests that individual hospitals are an appropriate target for interventions to improve outcomes in colorectal operations performed on frail patients.