Policymakers are increasingly targeting readmission for quality improvement and cost savings. Our objective was to characterize readmission following surgical procedures and estimate cost savings if readmissions are reduced.

Eligible patient-level records from the National Surgical Quality Improvement Program (NSQIP), years 2005-2008, were linked to Medicare inpatient claims data using indirect patient identifiers. Risk factors, indication for surgery (ICD9 code), and 30-day postoperative adverse events (PAE) were determined from NSQIP while 30-day readmission and costs were determined from Medicare. Poisson models were developed to determine incident rates of readmission, accounting for mortality.

Of the 114,288 patients in the linked database who were discharged alive, 16,541 were readmitted within 30 days of surgery. The incident rate of readmission, accounting for mortality, was 15.7%. Procedures most frequently associated with readmission were open colectomy, carotid artery procedures, and lower extremity bypass. Indications for surgery most frequently associated with later readmission were arterial aneurysms, atherosclerosis, arterial occlusion, colon cancer and abdominal hernia. Patients with any PAE had an incident rate of 30-day readmission of 42.9%, while patients with no PAE had an incident rate of 10.8%. The average Medicare payment for readmission was $10,684 (SD $13,751). Readmissions associated with a prior PAE cost on average $2,524 more than readmissions with no associated PAE. Reducing the complication rates for the above three procedures by a relative 5% each would result in an estimated savings of more than $19.1 million per year.
Costs associated with 30-day readmission and estimated savings if PAE are reduced by a relative 5%Open ColectomyCarotid ProceduresLower Extremity BypassPAE rate28.0%5.6%20.9%Number of discharges/year^297,902115,04063,585Incident rate of 30-day readmission if any PAE35.1%65.2%60.6%Incident rate of 30-day readmission if no PAE11.3%9.3%14.6%Mean cost of a 30-day readmission if any PAE$11,682$12,556$11,399Mean cost of a 30-day readmission if no PAE$8,171$10,865$10,345Reduce PAE rate by relative 5%:Reduced PAE rate26.6%5.3%19.8%Estimated readmissions saved per 1000 patients undergoing procedure3.31.64.8Estimated annual costs saved$13.2 million$2.3 million$3.6 millionPAE = 30-day postoperative adverse event recorded in NSQIPFor patients discharged alive within 30-days of primary procedure^Nationwide Inpatient Sample, 2008

Open Colectomy  Carotid Procedures  Lower Extremity Bypass  PAE rate  28.0%  5.6%  20.9%  Number of discharges/year^  297,902  115,040  63,585  Incident rate of 30-day readmission if any PAE  35.1%  65.2%  60.6%  Incident rate of 30-day readmission if no PAE  11.3%  9.3%  14.6%  Mean cost of a 30-day readmission if any PAE  $11,682  $12,556  $11,399  Mean cost of a 30-day readmission if no PAE  $8,171  $10,865  $10,345  Reduce PAE rate by relative 5%:        Reduced PAE rate  26.6%  5.3%  19.8%  Estimated readmissions saved per 1000 patients undergoing procedure  3.3  1.6  4.8  Estimated annual costs saved  $13.2 million  $2.3 million  $3.6 million

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Readmission following surgical procedures is common and represents an opportunity for quality improvement and cost savings.