Body Mass Index Is Associated with Proteinuria in Stage 2-3a but not Stage 3b-4 CKD Patients: An Observational Cross-sectional Study

Abstract Background: To investigate the relationship between body mass index (BMI) and proteinuria in stage 2-4 chronic kidney disease (CKD) patients. Methods: This study conducted a multicenter, cross-sectional study of 804 stage 2-4 CKD patients. Multivariate regression analysis, One-way ANOVA and subsequent multiple comparisons analysis were used to explore the relationship between BMI and proteinuria in pre-dialysis CKD patients. Results: Among stage 2-4 CKD patients, those with excessive proteinuria accounted for 85.32% of the total. BMI was an independent risk factor for the presence of proteinuria and positively correlated with the volume of proteinuria. Subgroup studies suggested that in stage 2-3a CKD patients, BMI was closely related to the presence and volume of proteinuria. However, in stage 3b-4 CKD patients, there was non-association between BMI and proteinuria. Furthermore, in stage 2-3a but not stage 3b-4 CKD patients, those with obesity (BMI≥ 28 kg/m2) had higher levels of proteinuria, compared with those with normal weight (BMI< 24 kg/m2) and overweight (24 kg/m2≤ BMI < 28 kg/m2). Conclusion: BMI is associated with the presence and volume of proteinuria in patients with early stage (stage 2-3a) CKD but not late stage (stage 3b-4) CKD. This result suggests that only in early stage CKD patients, weight control is beneficial for reducing proteinuria.Trial registration: ChiCTR-INR-17014069, Registered December 21, 2017.