IL6 and chronic kidney disease: Given that leptin has traditionally been considered a pro-inflammatory marker in the non-CKD/ESKD obese population (Supplementary Figure S3), these observations suggest that higher leptin levels may be associated with some (i.e., lower serum albumin), but not all (i.e., higher IL-6) inflammatory markers, and that the relationship between high leptin–low serum albumin may represent leptin’s relationship with specific inflammatory pathways.