Rationale & objective: Oxidative stress may contribute to the development of acute kidney injury (AKI) after cardiac surgery. Acetaminophen can be considered an antioxidant because it inhibits hemoprotein-catalyzed lipid peroxidation. We hypothesized that perioperative acetaminophen administration is associated with reduced AKI after cardiac surgery.
Study design: Retrospective observational cohort study.
Setting & participants: Patients aged≥18 years who had cardiac surgery were identified from 2 publicly available clinical registries: the Medical Information Mart for Intensive Care III (MIMIC-III) and the eICU Collaborative Research Database (eICU).
Exposure: Administration of acetaminophen in the first 48 hours after surgery.
Outcome: Severe AKI in the first 7 days after surgery, defined as stage 2 or stage 3 AKI according to KDIGO criteria.
Analytical approach: Multivariable cause-specific hazards regression analysis.
Results: We identified 5,791 patients from the MIMIC-III and 3,840 patients from the eICU registries. The overall incidence of severe AKI was 58% (3,390 patients) in the MIMIC-III cohort and 37% (1,431 patients) in the eICU cohort. Acetaminophen was administered in the early postoperative period to 4,185 patients (72%) and 2,737 patients (71%) in these 2 cohorts, respectively. In multivariable regression models, early postoperative use of acetaminophen was associated with a lower risk of severe AKI in both the MIMIC-III (adjusted hazard ratio [AHR], 0.86 [95% CI, 0.79-0.94]) and eICU (AHR, 0.84 [95% CI, 0.72-0.97]) cohorts. The benefit was consistent across sensitivity and subgroup analyses.
Limitations: No data on acetaminophen dose.
Conclusions: Early postoperative acetaminophen administration was independently associated with a lower risk of severe AKI in adults recovering from cardiac surgery. Prospective trials are warranted to assess the extent to which the observed association is causal and estimate the extent to which acetaminophen administration might prevent or reduce the severity of AKI.
Plain-language summary: There is uncertainty about whether antioxidant medications such as acetaminophen may protect against kidney injury. Therefore, we evaluated the associations between acetaminophen use and kidney outcomes in adults recovering from cardiac surgery in 2 large clinical registries. Acetaminophen treatment was significantly associated with a 14%-16% lower risk of severe and any-stage acute kidney injury but similar risks of kidney replacement therapy and in-hospital mortality. Our findings suggest that acetaminophen use may protect against kidney injury in adult patients recovering from cardiac surgery.
Keywords: Acetaminophen; acute kidney injury (AKI); analgesic; cardiac surgery; cardiac surgery-associated AKI; coronary artery bypass graft (CABG); in-hospital mortality; kidney replacement therapy (KRT); postoperative AKI; renal protection; valve repair; valve replacement.
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