Step 1. Using the Preop Creatinine (Highest within 60 days) and Postop Creatinine phenotypes, determine if any creatinine values are available.
- If no creatinine are available for both phenotypes, return 'Missing/Unknown' (value_code -999) and Stop.
- If values are found proceed to step 2.
Step 2. Check for values in the Preop Creatinine (Highest within 60 days).
- If no values exist, return ‘No preoperative creatinine‘(value_code -3).
- Otherwise, proceed to step 3.
Step 3. Use the value obtained from Preop EGFR (Lowest within 60 Days) phenotype to determine if preoperative renal failure is present:
- If BSA-Indexed EGFR < 15 mL/min/1.73 m2, then return 'Preoperative Renal Failure' (value_code -2) and stop.
- Otherwise, proceed to Step 4.
Step 4. Check for postop creatinine values using the Postop Creatinine phenotype
- If no values exist, then return 'No Postoperative Creatinine' (value_code -1).
- Otherwise, proceed to step 5.
- *If Scr value is = 0 mg/dL, then value is ignored (non-valid)
Step 5. Using Postop Creatinine, determine the highest value from either the 0-2 day creatinine or 2-7 day creatinine AND the values must be before anesthesia start date/time of subsequent surgery.
- If the 0-2 day creatinine is higher proceed to step 6a.
- If the 2-7 day creatinine is higher, proceed to step 6b.
Step 6a. Using the creatinine from the 0-2 day window,
- If this value is = 200% greater than baseline creatinine (i.e. = 3.0 times baseline), OR Scr > 4.0 mg/dl then return 'AKI Stage 3' (value_code 3)
- Otherwise, if this value is = 100% greater than baseline creatinine (i.e. = 2.0 times baseline), then return 'AKI Stage 2' (value_code 2)
- Otherwise, if this value is = 50% greater than baseline creatinine (i.e. = 1.5 times baseline), then return 'AKI Stage 1' (value_code 1)
- Otherwise if the creatinine value is equal to 0.3 mg/dL or greater than baseline creatinine then return 'AKI Stage 1' (value_code 1)
- Otherwise, return 'No AKI' (value_code 0).
Step 6b. Using the creatinine from the 2-7 day window, determine the following:
- If this value is = 200% greater than baseline creatinine (i.e. = 3.0 times baseline), OR Scr > 4.0 mg/dl then return 'AKI Stage 3' (value_code 3)
- Otherwise, if this value is = 100% greater than baseline creatinine (i.e. = 2.0 times baseline), then return 'AKI Stage 2' (value_code 2)
- Otherwise, if this value is = 50% greater than baseline creatinine (i.e. = 1.5 times baseline), then return 'AKI Stage 1' (value_code 1)
- Otherwise, return 'No AKI' (value_code 0).