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

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.

Patients with biopsy-proven NAFLD diagnosed in 1978-2006 in Malmö, 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 m²) 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 Malmö Preventive Project (MPP).

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 patients without CKD (P < 0.001). Regression analyses revealed that this increased mortality risk was explained by an increased prevalence of metabolic comorbidities (including diabetes mellitus), not CKD.

Mortality risk is significantly increased in NAFLD patients with long-term CKD due to metabolic comorbidities, not influenced by CKD per se.