CKD will be defined in 2 ways, detailed in Table 4: Grade 2 CKD or worse (binary; and also staged by CKD severity); and a stricter definition requiring ≥2 outpatient, abnormal eGFRs or albuminuria (or proteinuria) results, greater than 3 months apart, with no normal results in between.55, -57 eGFR will be calculated with only SCr if cystatin C is unavailable; a sensitivity analysis for patients with both analytes available will be conducted. This evidence concerns the gene CST3 and chronic kidney disease.