Varrassi 1994.

Methods	Study design: parallel RCT Study duration: not reported Study follow‐up: 24 h post‐operatively
Participants	Country: Italy Setting: single centre Inclusion criteria: patients undergoing elective cholecystectomy Number: treatment group (48); control group (47) Mean age ± SE (years): treatment group (52.5 ± 1.4); control group (50.2 ± 1.6) Sex (M/F): treatment group (17/31); control group (15/32) Exclusion criteria: pregnancy; history of peptic ulceration; coagulopathies; impaired kidney function; allergy or intolerance to NSAIDs; alcohol or opioid abuse; children; > 65 years
Interventions	Treatment group Ketorolac: 30 mg IM before surgery then 2 mg/h IV infusion for 24 h Control group Normal saline: 1 mL IM then 2 mL/h IV infusion for 24 h
Outcomes	Post‐operative SCr
Notes	Funding Source: supported in part by CNR Grants SCr level taken in recovery (and after first IM injection of ketorolac/placebo) is used as baseline SCr level. No pre‐operative SCr reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Study was described as randomised, method of randomisation was not reported
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgement
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Insufficient information to permit judgement
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information to permit judgement
Incomplete outcome data (attrition bias) All outcomes	Low risk	5 out of 100 patients were withdrawn from the study after randomisation and administration of the study drug. Reasons for missing outcome data unlikely to be related to true outcome
Selective reporting (reporting bias)	Low risk	Study protocol matches outcomes presented
Other bias	Unclear risk	Insufficient information to permit judgement

AKI ‐ acute kidney injury; ASA ‐ American Society of Anesthesiologists; CrCl ‐ creatinine clearance; DM ‐ diabetes mellitus; eGFR ‐ estimated glomerular filtration rate; ESKD ‐ end‐stage kidney disease; GI ‐ gastrointestinal; ICU ‐ intensive care unit; IM ‐ intramuscular; IV ‐ intravenous; MI ‐ myocardial infarction; NSAIDs ‐ nonsteroidal anti‐inflammatory drugs; POD ‐ post‐operative day/s; RRT ‐ renal replacement therapy; SCr ‐ serum creatinine