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Your next patient is scheduled for major noncardiac, nonurologic surgery. Based on a recent study, which of the following patients has the LOWEST risk of postoperative acute kidney injury (AKI)?
(A) 70-year-old female X(B) 40-year-old female ✔
(C) 40-year-old male X
Gain insight on this topic, and many others, with Summaries of Emerging Evidence (SEE) 2024 – now available. The content is aggregated from 30 international medical journals to streamline your learning and improve your practice.
Acute kidney injury (AKI) after noncardiac surgery increases mortality, morbidity, and hospital costs. The current literature lacks definitive studies identifying the association of sex and age on postoperative AKI, although there is speculation that female sex hormones play a protective role. The authors of a recent study hypothesized that the risk of postoperative AKI would be lower in females than similarly aged males and that this risk would increase with age in female patients.
This large retrospective cohort study examined data from 46 institutions that participated in the Multicenter Perioperative Outcomes Group database between 2013 and 2019. The study population included inpatient adults who underwent major noncardiac, nonurologic surgeries. Certain case characteristics were also excluded, including cases less than 60 minutes; electroconvulsive therapy; organ procurements; and transplant, obstetric, and pain procedures. Patients were classified into one of 4 groups based on sex and age older or younger than 50 years. The age of 50 was chosen to separate the age groups because it is considered the typical reference cutoff for menopause. AKI was defined as a creatinine rise of 0.3 mg/dL or greater within 48 hours, or more than 1.5 times the baseline within the first 7 days. A post hoc sensitivity analysis separated males and females between the ages of 20 years and 90 years into 5-year increments.
A total of 390,382 patients were included in the final analysis. Postoperative AKI occurred in 6.6% of all patients. Female patients younger than 50 years had the lowest rate of postoperative AKI (3.7%), while female patients older than 50 years had a rate of 6.5%. Male patients had a higher rate of postoperative AKI compared with female patients. Male patients younger than 50 years had a rate of 5.9%, while male patients older than 50 years had a rate of 8.3%. After adjusting for covariates, female patients younger than 50 years continued to have the lowest odds of AKI. Ascending age analysis showed a gradual increase in risk for females (Figure 1).
Figure 1. Association of age and sex with odds of postoperative acute kidney injury based on ascending age groups. Dot demonstrates odds ratio, and line displays 95% CI. Used with permission, from Privratsky JR, Fuller M, Raghunathan K, et al. Postoperative acute kidney injury by age and sex: a retrospective cohort association study. Anesthesiology. 2023;138(2):184-194. doi:10.1097/ALN.0000000000004436
In summary, this study showed that younger female patients have a lower risk for postoperative AKI after noncardiac surgery, with a gradual loss of protection with increasing age.
Reference
Date of last update: January 17, 2024
