Nephrotic syndrome in diabetic kidney disease: An evaluation and update of the definition

Background - Nephrotic syndrome is defined as urine total protein excretion greater than 3.5 g/d or total protein-creatinine ratio greater than 3.5 g/g, low serum albumin level, high serum cholesterol level, and peripheral edema. These threshold levels have not been rigorously evaluated in patients with diabetic kidney disease or by using urine albumin excretion, the preferred measure of proteinuria in patients with diabetes. Study Design - Diagnostic test study. Setting Participants - Adults with type 2 diabetes, hypertension, and urine total protein level greater than 0.9 g/d enrolled in the Irbesartan in Diabetic Nephropathy Trial. Index Test - Baseline measures of proteinuria (total protein and albumin excretion and protein-creatinine and albumin-creatinine ratios). Linear regression to relate measures. Reference Test - Other signs and symptoms of nephrotic syndrome at baseline (serum albumin <3.5 g/dL, serum total cholesterol > 260 mg/dL or use of a statin, and edema or use of a loop diuretic); progression of chronic kidney disease during follow-up (doubling of baseline serum creatinine level or requirement for dialysis or kidney transplantation). Logistic regression to relate ?