How is rate of loss of kidney function monitored?
Kidney function is monitored with serum creatinine (or eGFR correlates as outlined previously) and urinalysis.
A certain degree of fluctuation in serum creatinine can be expected and is usually related to changes in volume status, medications, and diet.
Creatinine values should be viewed over time to judge progression of CKD.
Creatinine-based GFR-estimating equations are less accurate in elderly patients and lead to overdiagnosis of CKD, particularly in those patients with higher eGFR.
Directly measuring creatinine clearance or using creatinine in combination with cystatin C–based eGFR equations can be used to further assess kidney function in older patients if a definitive diagnosis of CKD is required (e.g., a potential kidney donor).
A rise in urine protein excretion (or a failure to decrease urine protein excretion following treatment) is also an indicator of disease activity and progression of kidney disease.
Therapy should be aimed at reducing proteinuria to slow the progression of kidney disease. This can be done by treating the underlying disease, if possible, or using inhibitors of the renin angiotensin system (such as angiotensin-converting enzyme [ACE] inhibitors or angiotensin receptor blockers [ARBs] but not in combination) to decrease proteinuria.