Nonalcoholic Fatty Liver Disease: A New CKD Risk Factor?

Nonalcoholic fatty liver disease (NAFLD), in terms of both presence and severity, is an independent risk factor for CKD, concludes a meta-analysis in PLOS Medicine.

A systematic review was performed to identify observational studies assessing NAFLD by histologic, imaging, or biochemical findings and to assess CKD on the basis of estimated GFR or proteinuria. Thirty-three studies that included a total of 63,902 participants were identified. Of those, 20 studies provided individual participant data on 29,282 patients. A meta-analysis was performed to determine whether the presence of NAFLD affected the risk of CKD, after confounders were accounted for, and whether NAFLD severity affected the severity of CKD.

Participants with NAFLD were at higher risk for CKD: odds ratio (OR) 2.12 for prevalent CKD and hazard ratio (HR) 1.79 for incident CKD. The associations were stronger for nonalcoholic steatohepatitis than for simple steatosis: OR 2.53 for prevalent CKD and HR 2.12 for incident CKD. For patients with advanced hepatic fibrosis, the OR for prevalent CKD was 5.20, and the HR for incident CKD was 3.29, compared with patients with nonadvanced fibrosis.

The associations were significant in patients with and without diabetes and after adjustment for traditional CKD risk factors. They were also independent of whole-body and abdominal obesity and insulin resistance. Positive associations between NAFLD severity and CKD stage were found on analysis of both cross-sectional and longitudinal data.

The meta-analysis supports recent evidence suggesting an association between NAFLD and CKD. The findings suggest that patients with NAFLD should be screened for CKD, even in the absence of traditional risk factors, especially when nonalcoholic steatohepatitis or advanced fibrosis is suspected. The implications for treatment of NAFLD patients with CKD are discussed, along with the need for further research into the mechanisms of the association [Musso G, et al. Association of non-alcoholic fatty liver disease with chronic kidney disease: a systematic review and meta-analysis. PLoS Med 2014; 11:e1001680. doi: 10.1371/journal.pmed.1001680].