The impact of preoperative serum lactate dehydrogenase on mortality and morbidity after noncardiac surgery.

Preoperative serum lactate dehydrogenase (LDH) has been reported to be associated with adverse outcomes following thoracic surgery. However, its association with outcomes in noncardiac surgery as a whole has not been investigated. We conducted a retrospective cohort study at West China Hospital, Sichuan University, from 2018 to 2020, including patients undergoing noncardiac surgery. Multivariable logistic regression and propensity score weighting were employed to assess the link between LDH levels and postoperative outcomes. Preoperative LDH was incorporated into four commonly used clinical models, and its discriminative ability, reclassification, and calibration were evaluated in comparison to models without LDH. Among 130,879 patients, higher preoperative LDH levels (cut-off: 220 U/L) were linked to increased in-hospital mortality (4.382% vs. 0.702%; OR 1.856, 95% CI 1.620-2.127, P < 0.001), myocardial injury after noncardiac surgery (MINS) (3.012% vs. 0.537%; OR 1.911, 95% CI 1.643-2.223, P < 0.001), and ICU admission (15.010% vs. 6.414%; OR 1.765, 95% CI 1.642-1.896, P < 0.001). The inverse probability of treatment-weighted estimation supported these results. Additionally, LDH contributed significantly to four surgical prognostic models, enhancing their predictive capability. Our study revealed a significant association between preoperative LDH and in-hospital mortality, MINS, and ICU admission following noncardiac surgery. Moreover, LDH provided supplementary predictive information, extending the utility of commonly used surgical prognostic scores.