DIABETES MANAGEMENT
The treatment of patients early in diabetic CKD is often the responsibility of primary care providers, who are faced with the daunting task of addressing the renal dosing of medications. The eGFR or eCrCl needs to be utilized to adjust diabetic medications, largely to avoid hypoglycemia. To alleviate some of the difficulty, the KDIGO CKD stage and the eCrCl and eGFR for diabetic medications are delineated in Table 2.1
Note that the guidelines are not meant to be strictly adhered to but rather are intended as a tool for managing the patient with CKD. Clinically significant patient factors need to be considered to adequately adjust drugs in CKD. Also, as new data become available from postmarketing reports, dosing adjustments, added precautions, or updated risk factors in these fragile patients may need to be incorporated into the guidelines. As new diabetic medications are approved by the FDA, kidney-specific dosing will continue to be a moving target.
While making lifestyle changes is very important early in diabetes, by the time diabetic nephropathy manifests, more aggressive action is warranted.12 A part of the diabetic microvascular triad (along with retinopathy and neuropathy), nephropathy signals existing and irreversible organ damage. Before instituting treatment to delay diabetic nephropathy progression, an A1C goal needs to be established. The long-standing goal has been an A1C < 7%, according to guidelines established by the American Diabetes Association, or 6.5%, as recognized by the American Association of Clinical Endocrinologists.13 The Diabetes Control and Complications Trial (DCCT) demonstrated microvascular benefit of tight glycemic control in type 1 diabetic patients when the A1C was maintained at an average of 7.2% (versus 9.1% in conventional therapy).14 The United Kingdom Prospective Diabetes Study similarly demonstrated microvascular benefit with intensive blood glucose control in type 2 diabetic patients who were maintained at a median A1C of 7% compared to the conventional treatment group maintained at an A1C of 7.9%.15
In January 2013, Perkovic and colleagues, in a post hoc analysis of the ADVANCE Trial, showed that maintaining an A1C between 6.5% and 7% in a patient with diabetes and macroalbuminuria (UACR > 300 μg/mg) slows progression to kidney failure.16 The time needed to treat with intensive glucose control was five years, and the number needed to treat was 41. Thus, for every 41 patients with diabetes, CKD, and ALB whose A1C is below 7%, one will not progress to kidney failure in five years of treatment.
The five-year lead time is troublesome, however. It discourages many patients from taking steps to achieve strict glycemic control; a significant number fail to follow their diabetic diets or take their medications until the damage is done. For the elderly kidney patient with diabetes and multiple other comorbidities, aggressively managing diabetes may result in hypoglycemia.12 On balance, the slight loss of kidney function five years hence is less problematic than the present risk for a fall and resulting hip fracture due to hypoglycemia. For this reason, the KDOQI glycemic guidelines suggest an A1C between 7% to 7.5% as the goal for those with significant comorbidities.12
On the next page: Diabetic medication dosing for CKD >>