Further adjusting for residual kidney function biomarkers (serum β-trace protein, β2 microglobulin and cystatin C) in addition to the variables in Model 4 [demographics (age, sex and race), clinical characteristics (body mass index, residual kidney function as defined by self-reported ability to produce >1 cup of urine daily, ICED score, diabetes and cardiovascular disease), laboratory tests (albumin, phosphate, creatinine and Kt/VUREA)], did not change the direction of effect for p-cresol sulfate and phenylacetylglutamine (S10 Table). This evidence concerns the gene CST3 and diabetes mellitus.