Key result
Higher preoperative ALT within normal limits is linked to ~72% higher risk of marked postoperative elevation.
Why the study?
Modestly elevated serum ALT levels correlate with morbidity and mortality in the general population, but the perioperative significance of mildly elevated preoperative ALT in surgical patients remains unclear.
Does higher preoperative ALT increase the risk of marked postoperative ALT elevation in adults undergoing non-hepatic, non-cardiac surgery?
Cohort (n=43,892)
No
Does higher preoperative ALT increase the risk of marked postoperative ALT elevation in adults undergoing non-hepatic, non-cardiac surgery?
Odds Ratio: 1.72 (95% CI 1.36–2.16)
Absolute Event Rate: 2.7% vs 1.6%
p-value: p=<0.001
Even mildly elevated preoperative ALT within the conventional normal range is associated with increased risk of postoperative liver injury and 1-year mortality.
Higher preoperative ALT may flag elevated postoperative liver injury risk in non-cardiac surgery; extends population-level associations but leaves causal effects and practice change open.
Background: Modestly elevated serum alanine aminotransferase (ALT) levels are associated with increased morbidity and mortality in the general population; however, the perioperative significance of mildly elevated preoperative ALT levels in surgical patients remains unclear. Methods: This retrospective cohort study included adults undergoing non-hepatic, non-cardiac surgery at Samsung Medical Center. Patients with preoperative ALT measured within 3 months and <2 times the upper limit of normal (ULN) were eligible. Preoperative ALT was categorized as lower (men 0–34 U/L; women 0–22 U/L) or higher (men 35–82 U/L; women 23–66 U/L). The primary outcome was marked postoperative ALT elevation, operationally defined as any postoperative ALT value > 5 times the institutional ULN within 21 days after surgery. Propensity score matching was performed. Secondary outcomes included long-term ALT elevation, defined as an increase from the preoperative ALT value to >2 times the ULN at the last available measurement within 1 year after surgery, and 1-year all-cause mortality. Results: Among 43,892 patients, 7740 (17.6%) were classified into the higher ALT group, and marked postoperative ALT elevation occurred in 733 patients (1.7%). After 1:1 propensity-score matching, 7660 patient pairs were analyzed, and marked postoperative ALT elevation occurred more frequently in the higher than in the lower ALT group (2.7% [204/7660] vs. 1.6% [121/7660]; OR 1.72, 95% CI 1.36–2.16; p < 0.001). Higher preoperative ALT was also associated with long-term ALT elevation (OR 4.96, 95% CI 3.65–6.74; p < 0.001) and increased 1-year mortality (5.4% vs. 4.4%; OR 1.25, 95% CI 1.08–1.45; p = 0.003). Conclusions: Higher preoperative ALT was associated with marked postoperative ALT elevation, long-term ALT elevation, and 1-year mortality, even within the conventional normal range. Preoperative ALT may therefore warrant consideration when evaluating postoperative risk.
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Choi et al. (2026) conducted a cohort in Adults undergoing non-hepatic, non-cardiac surgery (n=43,892). Higher preoperative ALT (men 35–82 U/L; women 23–66 U/L) vs. Lower preoperative ALT (men 0–34 U/L; women 0–22 U/L) was evaluated on Marked postoperative ALT elevation (>5 times ULN within 21 days after surgery) (OR 1.72, 95% CI 1.36-2.16, p=<0.001). Higher preoperative ALT within the conventional normal range was associated with a significantly increased risk of marked postoperative ALT elevation compared to lower preoperative ALT (OR 1.72).
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