Acute kidney injury after non-cardiac major surgery: has it reduced?

Background: It remains unclear whether the incidence of post-operative acute kidney injury (PO-AKI) has been reduced despite the recent emphasis on its early recognition and prevention in clinical practice. We aimed to investigate the trend in the incidence of PO-AKI and to identify the associated factors affecting its changes.

Methods: We gathered clinical data from patients who underwent non-cardiac major surgeries at three referral hospitals from 2005 to 2020. PO-AKI was defined as KDIGO AKI criteria within 7 days after surgery. Severe PO-AKI (S-PO-AKI) was defined as stage 2 or 3 AKI. The temporal change of PO-AKI was evaluated by joinpoint regression analysis and multivariable logistic regression based on a 3-year interval.

Results: Among 138 235 patients, 8156 (5.9%) PO-AKI and 1127 (0.8%) S-PO-AKI occurred, respectively. The patients enrolled in recent years were older and more were women. They had more comorbidities and a higher PO-AKI risk compared with those included in past years. As time passed, the PO-AKI incidence decreased from 8.6% in 2005-07 to 5.1% in 2017-20, whereas S-PO-AKI incidence did not change (0.8% to 0.9%). In joinpoint analysis, PO-AKI incidence tended to decrease with annual percentage change (APC) of -4.2% per year [95% confidence interval (CI) -5.5% to -2.8%, P-value <.001), although S-PO-AKI did not (APC 0.9%, 95% CI -1.1 to 2.9%, P-value = .347). Similarly, the overall PO-AKI incidence decreased but S-PO-AKI did not, even after adjusting covariables.

Conclusion: The incidence of PO-AKI has decreased recently despite the increase in known risk factors; however, the incidence of S-PO-AKI has not decreased in recent years.

Trial registration information: ClinicalTrials.gov Identifier: NCT05986474. Name of registry: Development of Synthetic Medical Data Generation Technology to Predict Postoperative Complications. URL: https://classic.clinicaltrials.gov/ct2/show/NCT05986474. Date of registration: 14 August 2023. Date of enrollment of the first participant to the trial: 27 September 2022, retrospectively registered.