Increased mortality in non-alcoholic fatty liver disease with chronic kidney disease is explained by metabolic comorbidities

Background: There is a close association between non-alcoholic fatty liver disease (NAFLD) and prevalent chronic kidney disease (CKD). Few longitudinal studies exist. No previous study has investigated to what extent CKD affects mortality in biopsy-proven NAFLD. Our aim was to investigate the long-term risk of developing CKD in biopsy-proven NAFLD and its effect on mortality. Methods: Patients with biopsy-proven NAFLD diagnosed in 1978-2006 in Malmo, Sweden were included. Estimated glomerular filtration rate (eGFR) at baseline and last follow-up was calculated with the CKD-EPI equation. CKD 3-5 (< 60 mL/min/1.73 m(2)) was classified as CKD. Hospital medical records were extensively scrutinized from inclusion to endpoint (death or end of 2016). The prevalence of CKD was compared to a control group from the population-based prospective cohort Malmo Preventive Project (MPP). Results: 120 patients with biopsy-proven NAFLD were included. Mean age was 52.5 years and mean follow-up time 19.5 years. At baseline CKD prevalence in NAFLD was only significantly higher in the highest age group compared to controls (> 55 years, 25% vs. 9.5%, P=0.003), and no significant difference was seen at follow-up (in total 37.5% vs. 30.8%, P=0.124). NAFLD patients with long-term CKD had significantly higher crude overall mortality rate than NAFLD without CKD (P<0.001). Regression analyses revealed that this increased mortality patients risk was explained by an increased prevalence of metabolic comorbidities (including diabetes mellitus), not CKD. Conclusion: Mortality risk is significantly increased in NAFLD patients with long-term CKD due to metabolic comorbidities, not influenced by CKD per se. (C) 2019 Elsevier Masson SAS. All rights reserved.