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Table 1 Data parameters used in calculations, plausible ranges, sources and assumptions

From: Potential hospital cost-savings attributed to improvements in outcomes for colorectal cancer surgery following self-audit

Description Estimate (plausible range) Source
Surgical cases per year (for one surgeon) Scenario 1: 201 [11](<7, ≥7, over 15 per 3 months)
  Scenario 2: 40  
  Scenario 3: 70  
% reduction in adverse event rates Scenario 1: 50% (base effect) [4, 17, 2224, 30, 31]
  Scenario 2: 25% (small effect)  
  Scenario 3: 75% (large effect)  
% of colon and rectal surgery cases   
   Colon 68.7-75.9% [11]
   Rectal 24.1-31.3%  
Baseline adverse event rates2,3   
Anastomotic leak 4.4% (0.5-8.2) Mean of low/high values from up to 11 studies [4, 1019, 22] (see Table 2)
Wound infection 5.6% (2.1-9.1%)  
DVT 3.5% (0.3-6.7%)  
Respiratory complications (pulmonary embolism, infection, pneumonia) 5.5% (0.2-10.7%)  
Return to operating theatre 7.5% (2.7-12.2%)  
Post-op deaths (<30 days) % 3.3% (0.2-6.4%) As above
(% attributed to complications) (16%) [11]
Hospital costs (AUD 2009):   AR-DRGs code (ALOS):
   Rectal resection with complications $33,277 G01A (18.4 days)
   Rectal resection with no complications $18,094 G01B (9.8 days)
   Colon procedures with complications $30,899 G02A (17.8 days)
   Colon procedures with no complications $14,283 G02B (8.2 days)
12-month subscription to 'surgical performance' self-audit software4 $250 US$200
Data entry of surgical outcomes into audit software5 - performed by health information manager, 20 minutes per audit $16.67 per audit Based on salary $50 per hour
  1. Abbreviations: ALOS - average length of stay, DVT - deep vein thrombosis, AR-DRG - Australian Refined Diagnostic Related Group
  2. 1. Scenario 1 would apply to the majority of surgeons in Australia and New Zealand [11].
  3. 2. Implicit in the plausible range of complication rates listed above are the variations reflected in the usual population of cases requiring colon or rectal surgery, i.e., a mix of emergency and elective cases, colon and rectal cases, age, Dukes stage and presence of comorbidity.
  4. 3. As there is no evidence on extent of type of multiple complications occurring concurrently with colorectal surgery patients, the estimates assume mutually exclusive complication rates. An exception is '30-day mortality' where the percentage of 30-day deaths attributed to complications is 16% and costs were adjusted down to avoid double-counting.
  5. 4. Self-audit process involves feedback with peers - any attendant costs here were not included. It is assumed peer discussions would be periodically scheduled in normal practice.
  6. 5. Data entry is assumed to incur the time of a health info manager.