Is Annual Preoperative Utilization an Indicator of Postoperative Surgical Outcomes? A Study in Medicare Expenditure

Data on the association of high preoperative healthcare utilization and adverse clinical outcomes are scarce. We sought to evaluate the role of annual preoperative expenditure (APE) as a surrogate for latent variables of risk for adverse short-term postoperative outcomes.

Low and super-utilizers who underwent abdominal aortic aneurysm repair, coronary artery bypass graft, colectomy, total hip arthroplasty, total knee arthroplasty, or lung resection between 2013 and 2015 were identified from 100% Medicare Inpatient Standard Analytic Files. To assess the association between APE and postoperative outcomes, multivariable logistic regression was utilized.

Among 1,049,160 patients, 788,488 (75.1%) and 21,700 (2.1%) patients were preoperative low- and super-utilizers, respectively. Median APE was more than 60 times higher among super-utilizers than low-utilizers ($57,160 vs. $932), as was the cost of the surgical episode ($21,141 vs. $13,179). The predictive ability of APE ranged from 0.683 (95% CI 0.678-0.687) for 90-day readmission to 0.882 (95% CI 0.879-0.886) for a complication at the index hospitalization. Among super-utilizers, the odds of a complication during the surgical episode was nearly double versus low-utilizers (OR = 1.96, 95% CI 1.89-2.04). Super-utilizers also had an increased odds of 30-day readmission (OR = 1.64, 95% CI 1.58-1.69) and mortality (OR = 2.22; 95% CI 2.04-2.42).

APE was able to predict adverse postsurgical outcomes including complications during the surgical episode, readmission, and 90-day mortality. APE should be considered in the assessment of patient populations when defining risk of adverse postoperative events.