Type 2 Diabetes and Chronic Kidney Disease in an Elderly Woman: How Would You Treat?

Discussion
Lenore has class 3B chronic kidney disease (CKD; GFR 45 to 30 mL/min per 1.73m²) and so I would immediately reduce the metformin(Drug information on metformin) dose by half, to 850 mg daily. Some clinicians would probably stop the metformin completely. Renal function should be closely monitored in patients with class 3B CKD; once GFR is <30 mL/min per 1.73m², metformin should be stopped.¹ She also has symptomatic hypoglycemia, most likely caused by the glipizide(Drug information on glipizide), so I would stop that immediately.

The challenge now is to decide what agent to use to control Lenore’s blood sugar level, in light of her CKD. Insulin might be a logical choice, but the patient is obese and has a history of hypoglycemia when taking even low-dose sulfonylurea. A dipeptidyl peptidase-4 (DPP-4) inhibitor such as linagliptin has very low renal clearance so would be an option, but it is only shown to reduce HbA_1C by 0.4% to 0.7%. The other DPP-4 inhibitors (eg, saxagliptin, sitagliptin(Drug information on sitagliptin)) have significant renal clearance and so the dose would need to be reduced. A glucagon(Drug information on glucagon)-like peptide-1 (GLP-1) agonist would be my choice. Exenatide is eliminated via the kidney, so the dose should be reduced once GFR <50 mL/min per 1.73 m² and not used with GFR <30 mL/min per 1.73 m². Liraglutide has minimal renal clearance and can be used safely in patients with CKD. It will provide about 1% reduction in HbA_1C. There is also evidence that GLP-I agonists reduce triglyceride levels and systolic blood pressure.² 

I would be happy to reach an HbA_1C level of <8% and would not push her to an HbA_1C level of <7%, given her CKD, her age, and her long history of diabetes.

I would also begin therapy with a statin. Cardiovascular disease is the major cause of death in patients with CKD, and statins have demonstrated success in reducing CVD in these patients.³  

References
1. Lipska KJ, Bailey CJ, Inzucchi SE. Use of metformin in the setting of mild-to-moderate renal insufficiency. Diabetes Care. 2011;34:1431-1437.
2. Reid T. Choosing GLP-1 receptor agonists or DPP-4 inhibitors: weighing the clinical trial evidence. Clin Diabetes. 2012;30:3-12.
3. Baigent C, Landray MJ, Reith C, et al. The effects of lowering LDL cholesterol with simvastatin(Drug information on simvastatin) plus ezetimibe(Drug information on ezetimibe) in patients with chronic kidney disease (Study of Heart and Renal Protection): a randomized placebo-controlled trial. Lancet. 2011;377:2181-2192.