Metabolic dysfunction-associated fatty liver disease and risk of incident chronic kidney disease: A nationwide cohort study

Aims: The recently proposed metabolic dysfunction-associated fatty liver disease (MAFLD) has been suggested to better reflect the metabolic components of fatty liver disease (FLD), compared to nonalcoholic fatty liver disease (NAFLD). This study investigated whether MAFLD identifies a higher proportion of individuals at risk of developing chronic kidney disease (CKD). Methods: 268,946 participants aged 40–64 years, who underwent National Health Insurance Service health examinations between 2009 and 2015 were included. Participants were categorized by presence of FLD, according to MAFLD or NAFLD. In participants with FLD, participants were categorized into three groups: non-metabolic risk (non-MR) NAFLD, MAFLD but not NAFLD, and overlapping FLD. Incident CKD was defined as the occurrence of eGFR < 60 mL/min/1.73m² or proteinuria (≥ trace) on two consecutive health examinations. Results: 73,726 (27.4%) and 88,762 (33.0%) participants had NAFLD and MAFLD, respectively. During a median follow-up of 5.1 years, CKD occurred in 8,335 (6.2/1,000 person-years) participants. Compared to non-NAFLD participants, the adjusted hazard ratio (aHR) for incident CKD was 1.33 (95% CI, 1.27–1.39; P < 0.001) for participants with NAFLD. Compared to non-MAFLD participants, the aHR for participants with MAFLD was 1.39 (95% CI, 1.33–1.46; P < 0.001). When the analysis was confined to participants with FLD, compared to non-MR NAFLD participants, the aHRs for participants with MAFLD but not NAFLD, and those with overlapping FLD were 1.18 (95% CI, 1.01–1.39; P = 0.040) and 1.36 (95% CI, 1.19–1.54; P < 0.001), respectively. Conclusion: MAFLD identified a higher proportion of individuals at risk of developing CKD than NAFLD.