BACKGROUND AND AIMS: The impact of metabolic syndrome (MetS) traits on chronic kidney disease (CKD) risk in metabolic dysfunction-associated steatotic liver disease (MASLD) is unknown. We investigated the impact of type and number of MetS traits and liver fibrosis on prevalent CKD and incident end-stage renal disease (ESRD) risk in SLD. METHODS: 234 488 UK Biobank participants' were analysed. Hepatic steatosis index (>
36 for SLD, <
30 for no SLD) and MRI-proton density fat fraction (≥ 5.56%) were used to identify SLD. MetS traits were identified using MASLD criteria. Advanced fibrosis (FIB-4 score >
2.67) was determined using FIB-4 scores. eGFR <
60 mL/min/1.73 m RESULTS: 102 410 participants (41.2%) had SLD. 64.4% had MetS. 1.3% had FIB-4 score >
2.67. With SLD and only one MetS trait, hypertension (OR 1.35, 95% CI 1.35-1.72) or type 2 diabetes (T2D) (OR 1.89, 95% CI 1.06-3.38) increased risk of prevalent CKD. MetS (≥ 3 traits) increased prevalent CKD risk (OR 1.94, 95% CI 1.75-2.15), which was further increased by advanced liver fibrosis (OR 4.29, 95% CI 3.36-5.47). CKD prevalence increased with increasing MetS traits. Over 13.6 years (median follow-up), MetS was associated with increased risk of developing ESRD (HR 1.70, 95% CI 1.19-2.43). CONCLUSIONS: In MASLD, hypertension, and T2D, number of MetS traits and liver fibrosis increased risk of prevalent CKD and presence of MetS increased the risk of incident ESRD.