Nonalcoholic fatty liver disease accelerates kidney function decline in patients with chronic kidney disease: a cohort study

This study aimed to investigate the association of nonalcoholic fatty liver disease (NAFLD) and its severity with the decline in kidney function in patients with chronic kidney disease (CKD). We conducted a cohort study of 1,525 CKD patients who underwent repeated health check-up examinations from January 2003 through December 2013. NAFLD was diagnosed by ultrasonography and its severity was assessed by the NAFLD fibrosis score. At baseline, the prevalence of NAFLD was 40.9%, and the mean estimated glomerular filtration rate (eGFR) was 59.1 ml/min/1.73 m(2). The average follow-up was 6.5 years. The age-and sex-adjusted decline in eGFR was greater in patients with NAFLD (-0.79% per year, 95% CI -1.31%, -0.27%) compared to those without it (0.30%, 95% CI -0.14%, 0.76%; p = 0.002). In multivariable adjusted models, the average difference in annual percent change in decline in eGFR comparing patients with NAFLD to those without NAFLD was -1.06% (-1.73%, -0.38%; p = 0.002). The decline in eGFR associated with NAFLD was greater in patients with higher NAFLD fibrosis score, in those with proteinuria or with low eGFR at baseline (<45 ml/min/1.73 m(2)), and in those who were smokers and hypertensive. Therefore, NAFLD is independently associated with CKD progression.