Duration of acute kidney injury predicts 90-day mortality and chronic kidney disease progression in elderly patients

Acute kidney disease beyond day 7 after major surgery: a secondary analysis of the EPIS-AKI trial

PURPOSE

Acute kidney disease (AKD) is a significant health care burden worldwide. However, little is known about this complication after major surgery.

METHODS

We conducted an international prospective, observational, multi-center study among patients undergoing major surgery. The primary study endpoint was the incidence of AKD (defined as new onset of estimated glomerular filtration rate (eCFR) < 60 ml/min/1.73 m2 present on day 7 or later) among survivors. Secondary endpoints included the relationship between early postoperative acute kidney injury (AKI) (within 72 h after major surgery) and subsequent AKD, the identification of risk factors for AKD, and the rate of chronic kidney disease (CKD) progression in patients with pre-existing CKD.

RESULTS

We studied 9510 patients without pre-existing CKD. Of these, 940 (9.9%) developed AKD after 7 days of whom 34.1% experiencing an episode of early postoperative-AKI. Rates of AKD after 7 days significantly increased with the severity (19.1% Kidney Disease Improving Global Outcomes [KDIGO] 1, 24.5% KDIGO2, 34.3% KDIGO3; P < 0.001) and duration (15.5% transient vs 38.3% persistent AKI; P < 0.001) of early postoperative-AKI. Independent risk factors for AKD included early postoperative-AKI, exposure to perioperative nephrotoxic agents, and postoperative pneumonia. Early postoperative-AKI carried an independent odds ratio for AKD of 2.64 (95% confidence interval [CI] 2.21-3.15). Of 663 patients with pre-existing CKD, 42 (6.3%) had worsening CKD at day 90. In patients with CKD and an episode of early AKI, CKD progression occurred in 11.6%.

CONCLUSION

One in ten major surgery patients developed AKD beyond 7 days after surgery, in most cases without an episode of early postoperative-AKI. However, early postoperative-AKI severity and duration were associated with an increased rate of AKD and early postoperative-AKI was strongly associated with AKD independent of all other potential risk factors.

Mortality Analysis in Geriatric Patients With Acute Kidney Injury Admitted in the Intensive Care Unit: A Single-Center Cross-Sectional Study

Introduction Acute kidney injury (AKI) is an abrupt reduction in kidney function that causes nitrogenous waste and other waste products to be retained. Methods This cross-sectional study was conducted from February 2015 to January 2016. The study received approval from the Independent Ethics Committee, which included patients over 60 with AKI. The study duration was 12 consecutive months to ascertain the etiology, severity, and hospital outcomes of AKI. Results The common etiologies of AKI included drug-induced (25%), age-related (21.67%), cardiac (13.33%), respiratory (20%), tropical (15%), and pancreatitis (15%) cases. Another predominant etiology observed was obstructive nephropathy (55%), with the highest (37.5%) mortality rate. The distribution of patients based on KDIGO criteria showed no significant difference in mortality percentages among classes (p=0.177). Conservative management without renal replacement therapy was the most common approach to treat AKI, with a 39% mortality rate. Conclusion Among different causes of AKI in the geriatric age group, drug-induced AKI, and obstructive nephropathy were predominantly associated with hospital mortality.

The duration of acute kidney injury is an additional parameter to predict 1-year survival in very elderly patients

Background

Acute kidney injury (AKI) is primarily defined and classified according to the magnitude of the elevation of serum creatinine (Scr). We aimed to determine whether the duration of AKI adds prognostic value in addition to that obtained from the magnitude of injury alone.

Methods

This retrospective study enrolled very elderly inpatients (≥75 years) in the Chinese PLA General Hospital from January 2007 to December 2018. AKI was stratified by magnitude according to KDIGO stage (1, 2, and 3) and duration (1-2 days, 3-4 days, 5-7 days, and >7 days). The primary outcome was the 1-year mortality after AKI. Multivariable Cox regression analysis was performed to identify covariates associated with the 1-year mortality. The probability of survival was estimated using the Kaplan-Meier method, and curves were compared using the log-rank test.

Results

In total, 688 patients were enrolled, with the median age was 88 (84-91) years, and the majority (652, 94.8%) were male. According to the KDIGO criteria, 317 patients (46.1%) had Stage 1 AKI, 169 (24.6%) had Stage 2 AKI, and 202 (29.3%) had Stage 3 AKI. Of the 688 study subjects, 61 (8.9%) with a duration of AKI lasted 1-2 days, 104 (15.1%) with a duration of AKI lasted 3-4 days, 140 (20.3%) with a duration of AKI lasted 5-7 days, and 383 (55.7%) with a duration of AKI lasted >7 days. Within each stage, a longer duration of AKI was slightly associated with a higher rate of 1-year mortality. However, within each of the duration categories, the stage of AKI was significantly associated with 1-year mortality. When considered separately in multivariate analyses, both the duration of AKI (3-4 days: HR=3.184; 95% CI: 1.733-5.853; P <0.001, 5-7 days: HR=1.915; 95% CI: 1.073-3.416; P=0.028; >7 days: HR=1.766; 95% CI: 1.017-3.065; P=0.043) and more advanced AKI stage (Stage 2: HR=3.063; 95% CI: 2.207-4.252; P <0.001; Stage 3: HR=7.333; 95% CI: 5.274-10.197; P <0.001) were independently associated with an increased risk of 1-year mortality.

Conclusions

In very elderly AKI patients, both a higher stage and duration were independently associated with an increased risk of 1-year mortality. Hence, the duration of AKI adds additional information to predict long-term mortality.