Acute kidney injury (AKI) is a common complication following non-cardiac surgery with adverse short- and long- term morbidity and mortality. Evidence shows that hypoalbuminemia is associated with increased AKI risk in patients with infectious diseases and cancer and following cardiac surgery and transplant surgery. However, little evidence is available on non-cardiac surgery population. Thus, we investigated the association between preoperative hypoalbuminemia and AKI following non-cardiac surgery. We retrospectively assessed perioperative risk factors and preoperative serum albumin concentration in 729 consecutive adult patients who underwent non-cardiac surgery from July 1, 2017, to June 30, 2018. Each patient was categorized according to maximal Kidney Disease Improving Global Outcomes criteria based on creatinine changes and urine output within the first week after surgery. Multivariate Logistic regression models were used to analyze the association between preoperative hypoalbuminemia and postoperative AKI. Of 729 patients, 188 (25.8%) developed AKI. AKI incidence was higher in patients with preoperative serum albumin < 37.5 g/L than in those with preoperative serum albumin ≥37.5 g/L [35.9% (98/273) vs. 19.7% (90/456), P < 0.001]. Multivariate logistic regression analysis showed that preoperative serum albumin < 37.5 g/L (odds ratio 1.892; 95% confidence interval 1.238–2.891; P = 0.003) was independently associated with postoperative AKI. Patients with preoperative serum albumin < 37.5 g/L tended to have a higher but not significant ratio in AKI stage 2 (2.6% vs 1.1%, P = 0.144) and much higher ratio in AKI stage 3 (4.8% vs 0.7%, P < 0.001) than those with preoperative serum albumin ≥37.5 g/L. AKI patients had a higher in-hospital mortality rate [6.9% (13/188) vs. 0.2% (1/541), P < 0.001]. Kaplan-Meier analysis revealed that the cumulative survival rate decreased with increasing AKI severity (P < 0.001). Postoperative AKI was also associated with other worse outcomes, such as prolonged mechanical ventilation [53.4 (33.0, 73.8) vs 14.7 (11.1, 18.3) hours, P < 0.001], intensive care unit stay [4.0 (3.1, 4.9) vs 2.0 (1.8, 2.3) days, P < 0.001], postoperative hospital stay [17.8 (14.8, 20.9) vs 12.3 (11.3, 13.3) days, P < 0.001], and higher total cost [13,453 (8538, 20,228) vs 11,306 (6277, 16,400) dollars, P < 0.001]. Preoperative hypoalbuminemia was independently associated with AKI after non-cardiac surgery, and postoperative AKI was associated with poor outcomes.

Background: Evidence has shown that preoperative hypoalbuminemia is independently associated with acute kidney injury (AKI) after non-cardiac surgery. However, little study has investigated the effects of administration of exogenous albumin early after non-cardiac surgery on postoperative AKI in patients with preoperative hypoalbuminemia.Methods: This study was a secondary analysis of the database of a previously conducted prospective cohort study. Data of 661 adult patients who underwent non-cardiac surgery and were admitted to Surgical Intensive Care Unit (SICU) after surgery from May 1, 2019, to November 30, 2020, were collected. 267 patients with preoperative hypoalbuminemia were screened, and divided into two groups according to whether they were administrated with exogenous albumin on the day of SICU admission. The demographic and perioperative data of the two groups were propensity-matched.Results：After propensity score matching, 64 pairs of patients were included in the final analysis. The patients of the albumin group showed a higher serum albumin level on postoperative day 1 than that in patients of the control group [31.3±3.4 vs. 29.7±3.8, P=0.008], however, no difference was observed in postoperative AKI incidence between the two groups (59.4% vs. 62.5%, P=0.717). Furthermore, there was no difference in other prognostic factors, such as the use and duration of mechanical ventilation, number of other postoperative complications, in-hospital mortality, length of SICU stay and postoperative hospital stay.Conclusions: The current study did not exhibit benefit of exogenous albumin administration early after non-cardiac surgery on the occurrence of postoperative AKI in patients with preoperative hypoalbuminemia, which needs to be confirmed by further large randomized controlled researches in the future.

Background: Acute kidney injury (AKI) is a frequent complication in intensive care unit (ICU) patients with acute brain injury. High-altitude hypoxia may aggravate renal vulnerability, but relevant evidence is limited. This study aims to investigate the incidence, risk factors, and outcomes of AKI among neurocritical patients at high altitude. Methods: Adult neurocritical patients admitted to the ICU of People’s Hospital of Xizang Autonomous Region (3,650 m) from January 2022 to February 2024 were retrospectively analyzed. AKI was defined using the 2012 KDIGO serum creatinine criteria. Multivariable logistic regression identified independent predictors, and hemoglobin levels were modeled with linear spline regression. Propensity score matching (PSM) was performed to evaluate the impact of specific interventions. Results: Among 390 patients, 83 (21.3%) developed AKI within 7 days of ICU admission. Independent predictors included older age (OR = 1.058 [1.032–1.087], p < 0.001), higher body mass index (OR = 1.130 [1.030–1.242], p = 0.010), lower Glasgow Coma Scale score (OR = 0.859 [0.795–0.924], p < 0.001), hypotension (OR = 2.659 [1.257–5.579], p = 0.010), contrast agent (OR = 2.480 [1.263–4.867], p = 0.008), high-dose loop diuretics (OR = 1.985 [1.117–3.555], p = 0.020), and baseline eGFR (OR = 1.033 [1.015–1.052], p < 0.001). Both low (180 g/L, OR = 2.031 [1.093–3.790], p = 0.025) hemoglobin levels increased AKI risk. PSM sensitivity analysis confirmed the association of high-dose loop diuretics with AKI (OR = 2.009, p = 0.011), while the effect of contrast agents lost significance after matching (OR = 1.505, p = 0.215). Patients with AKI had higher in-hospital mortality (34.9% vs. 11.7%, p < 0.001) and greater hospitalization costs (148.5 vs. 119.4 × 1,000 CNY, p = 0.001). Conclusion: At high altitude, AKI is common in neurocritical patients and independently associated with adverse outcomes. Beyond traditional risk factors, altitude-related erythrocytosis significantly contribute to AKI risk, suggesting that tailored renal protection strategies are necessary in high-altitude neurocritical care.