Relations of liver fat with prevalent and incident chronic kidney disease in the Framingham Heart Study: A secondary analysis.

Background & Aims: Prior studies demonstrated an association between non-alcoholic fatty liver disease and chronic kidney disease (CKD), though data are conflicting. We examined the association between liver fat and prevalent and incident CKD in the Framingham Heart Study (FHS).

Methods: We included FHS participants who underwent computed tomography (CT) from 2002 to 2005 (n = 1315). After excluding heavy alcohol use (n = 211) and missing covariates (n = 117), the final sample included 987 participants. For the incident CKD analysis, we excluded 73 participants with prevalent CKD. Liver fat was measured by the average liver attenuation on CT. Estimated glomerular filtration rate (eGFR) was obtained using the CKD Epidemiology Collaboration Creatinine-Cystatin C equation, and CKD was defined as eGFR < 60 ml/min/1.73 m . Microalbuminuria was defined by sex-specific urinary albumin-creatinine ratio cut-offs. Multivariable-adjusted regression models were performed to determine the association between liver fat and CKD.

Results: The prevalence of hepatic steatosis and CKD were 19% and 14% respectively (55.9% women, mean age 60 ± 9 years). After adjusting for covariates, we observed no significant associations between liver fat and CKD, microalbuminuria or eGFR in cross-sectional analyses. We observed positive associations between liver fat, incident microalbuminuria and reduced eGFR in age- and sex-adjusted models; these relationships were not significant in multivariable-adjusted models.

Conclusions: In this community-based cohort study, we did not observe significant associations between liver fat and prevalent or incident CKD with a median follow-up time of 12.5 years. The association between NAFLD and CKD may be accounted for by shared risk factors; confirmatory studies are needed.