Complement C3 and Nonalcoholic Fatty Liver Disease in Chronic Kidney Disease Patients: A Pilot Study

Context: Evidences have suggested complement C3 is a biomarker for nonalcoholic fatty liver disease (NAFLD) in the general population. Objective: The present study was conducted to explore the predictive function of C3 for NAFLD in chronic kidney disease (CKD) patients. Design, Setting, and Participants: CKD patients were recruited for evaluation of their liver function, kidney function, serum lipids, glycated hemoglobin, blood, and immune function. The glomerular filtration rate was calculated using the CKD-EPI equation. NAFLD was diagnosed according to predefined ultrasonographic criteria. Results: A total of 648 consecutive CKD patients were included, with 216 (33.3%) patients diagnosed with NAFLD. The NAFLD group had significant higher levels of serum protein, serum albumin, triglycerides, glycated hemoglobin, complement C3, hemoglobin ( p = 0.001), alanine aminotransferase ( p = 0.002), estimated glomerular filtration rate ( p = 0.007), and C4 ( p = 0.043) and lower levels of cystatin C, β₂-microglobulin, proteinuria ( p = 0.001), and high-density lipoprotein cholesterol ( p = 0.008). In a logistic regression model, only complement C3 (OR = 1.003; 95% CI 1.002–1.004, p = 0.001) was associated with a higher likelihood of being diagnosed with NAFLD. Finally, we constructed ROC curves for complement C3 for prediction of having NAFLD. The best cut-off for complement C3 was 993.5 mg/L and it yielded a sensitivity of 63.9% and a specificity of 70.1%. Conclusion: Our study revealed that complement C3 can be used as a surrogate biomarker of NAFLD in CKD patients.