Diuretics are often needed as well, especially as more advanced disease leads to greater retention of sodium and water. In general, at an eGFR <30 mL/min/1.73 m², loop diuretics are more effective than thiazide diuretics. Patients should also be strongly encouraged to maintain a low-salt diet.

Proteinuria. Proteinuria is a marker of glomerular injury, but it is also understood to contribute to CKD progression. In particular, proteins that are filtered in the glomerulus are reabsorbed in proximal tubule cells, where they trigger inflammation, apoptosis, and fibrosis. In addition, abnormal filtration of growth factors and cytokines also promotes tubular injury. Thus a reduction in proteinuria has been associated with a slower progression of chronic kidney disease, particularly among patients with diabetic disease.

Proteinuria must be regularly assessed in all patients. In nondiabetics, screening with urine dipstick is acceptable, but if positive, a spot urine protein : creatinine ratio should be performed for quantification. A 24-hour urine collection for protein can be performed; however, a spot sample is typically adequate and is easier for the patient. In diabetics, regular screening for microalbu-minuria should be performed early in the disease course.

ACE inhibitors and ARBs have been shown to reduce proteinuria, likely because of the reduction in intraglomerular pressure. Studies in diabetic patients have shown that these drugs reduce proteinuria and slow the decline of eGFR independent of their effect on systemic blood pressure.