Moderate and large volume nonmalignant pleural effusions independently associated with AKI: Study

Nonmalignant pleural effusion (NMPE) is common and remains a definite healthcare problem. Pleural effusion was supposed to be a risk factor for acute kidney injury (AKI). The incidence of acute kidney injury in NMPE patients and whether there is a correlation between the size of effusions and acute kidney injury is unknown. A study was done to assess the incidence of acute kidney injury in NMPE inpatients and its association with effusion size. They conducted a retrospective cohort study of inpatients admitted to the Chinese PLA General Hospital with pleural effusion from 2018-2021. All patients with pleural effusions confirmed by chest radiography (CT or X-ray) were included, excluding patients with a diagnosis of malignancy, chronic dialysis, end-stage renal disease (ESRD), community-acquired acute kidney injury, hospital-acquired AKI before chest radiography, and fewer than two serum creatinine tests during hospitalization. Multivariate logistic regression and LASSO logistic regression models were used to identify risk factors associated with AKI. Subgroup analyses and interaction tests for effusion volume were performed and adjusted for the variables selected by LASSO. Causal mediation analysis was used to estimate the mediating effect of heart failure, pneumonia, and eGFR < 60 ml/min/1.73m2 on AKI through effusion volume.

Results: NMPE was present in 7.8% of internal medicine inpatients. Of the 3047 patients included, 360 (11.8%) developed AKI during hospitalization. After adjustment by covariates selected by LASSO, moderate and large effusions increased the risk of acute kidney injury compared with small effusions (moderate: OR 1.47, 95%CI 1.11-1.94 p = 0.006; large: OR 1.86, 95%CI 1.05-3.20 p = 0.028). No significant modification effect was observed among age, gender, diabetes, bilateral effusions, and eGFR. Volume of effusions mediated 6.8% (p = 0.005), 4.0% (p = 0.046) and 4.6% (p < 0.001) of the effect of heart failure, pneumonia and low eGFR on the development of acute kidney injury respectively.

The incidence of acute kidney injury is high among NMPE patients. Moderate and large effusion volume is independently associated with acute kidney injury compared to small size. The effusion size acts as a mediator in heart failure, pneumonia, and eGFR.

Reference:

Wang, D., Niu, Y., Chen, D. et al. Acute kidney injury in hospitalized patients with nonmalignant pleural effusions: a retrospective cohort study. BMC Nephrol 25, 118 (2024). https://doi.org/10.1186/s12882-024-03556-4