Relationship between the neutrophil-to-lymphocyte ratio and estimated glomerular filtration rate in patients with primary aldosteronism: a cross-sectional study

Abstract

Objective: To investigate the associations between neutrophil-to-lymphocyte ratio (NLR) and estimated glomerular filtration rate (eGFR) in patients with primary aldosteronism (PA). Methods: This study was a cross-sectional study. Consecutive patients diagnosed with PA and admitted to the Second Affiliated Hospital of Nanchang University from October 2017 to April 2022 were enrolled. General information, blood routine, renal function, and other clinical data of the patients were collected. Based on the median NLR of the enrolled patients, NLR<median was defined as low NLR. Low eGFR was defined as an eGFR<60 ml·min-1·1.73 m-2. Multiple linear regression and multivariate logistic regression models, smooth curve fitting and threshold effect exploration were used to analyze the relationship between NLR and eGFR in PA patients, and stratified analysis and interaction tests were used to evaluate potential variables that may affect the correlation between NLR and eGFR. Results: This study finally included 743 PA patients, aged (50.3±10.4) years, 42.9% (319/743) were female, and the median NLR was 2.3. After adjusting for sex, age, body mass index (BMI) and other factors, multiple linear regression analysis showed that high NLR was negatively correlated with eGFR (β=-4.9, P=0.008), and multivariate logistic regression analysis showed that high NLR was associated with low eGFR (OR=3.1, P=0.002). In the corrected smooth curve, NLR is U-shaped correlation with eGFR, and the inflection point is at NLR=3.5. When the NLR was<3.5, the eGFR decreased with the increase of NLR (corrected β=-4.7, P<0.001); When the NLR was≥3.5, the eGFR increased with the increase of NLR (corrected β=5.8, P=0.031). The results of stratified analysis showed that there was an interaction between the association of NLR and eGFR with the presence or absence of hyperlipidemia (P interaction=0.017), and the correlation between NLR and eGFR was stronger in PA patients with hyperlipidemia. Conclusion: In the PA patients, there is a U-shaped relationship between NLR and eGFR, and higher NLR is associated with lower eGFR. PA patients with elevated NLR should undergo additional screening for chronic kidney disease and receive related preventive interventions.