Medical care of patients with diabetic nephropathy

Several issues are key in the medical care of patients with diabetic nephropathy. These include glycemic control, management of hypertension, and reducing dietary salt intake and phosphorus and potassium restriction in advanced cases.

A meta-analysis from the Cochrane Database shows a large fall in blood pressure with salt restriction, similar to that of single-drug therapy. All diabetic patients should consider reducing salt intake at least to less than 5-6 g/d, in keeping with current recommendations for the general population, and may benefit from lowering salt intake to even lower levels. Reducing dietary salt intake may help slow progression of diabetic kidney disease. Renal replacement therapy may be necessary in patients with end-stage renal disease (ESRD).

A 2012 post-hoc analysis of the data merged from the Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL) trial and the Irbesartan Diabetic Nephropathy Trial (IDNT) in 1177 patients demonstrated that a low-sodium diet (24-h urinary sodium/creatinine ratio (mmol/g) < 121) enhanced the renoprotective and cardioprotective effect of angiotensin receptor blockers (losartan or irbesartan) in type 2 diabetic patients with nephropathy. Compared with higher sodium intake groups, the patients in the low-sodium group had better renal (by 43%) and cardiovascular (by 37%) outcomes. These improved outcomes in the low-sodium group underscore the importance of recent calls for population-wide intervention to reduce dietary salt intake, particularly in patients with diabetes and nephropathy treated with angiotensin receptor blockers.