Case Study: Combination GLP-1/DPP-4 Therapy in Type 2 Diabetes
The use of combined GLP-1/DPP-4 medication therapy is not currently supported by American Diabetes Association guidelines.
History of present illness
The patient is a 63-year-old man who has had type 2 diabetes for 20 years. He was admitted to the hospital to undergo right robotic partial nephrectomy and has a history of renal mass.
- Obesity, BMI 31
Diabetes medication history
One year prior to admission, the patient was prescribed metformin and pioglitazone. Due to elevated HbA1c, liraglutide was added to his regimen. The patient gradually increased the dose of liraglutide from 0.6 mg to the current dose of 1.8 mg daily. Since starting liraglutide, the patient reports a 20-pound weight loss.
Three months ago, his diabetes medication regimen was adjusted due to elevated creatinine and worsening estimated glomerular filtration rate (eGFR). At that time, metformin use was recommended to be discontinued. In its place, the patient was recommended to start linagliptin 5 mg once daily in the morning, and continue liraglutide 1.8 mg once daily and pioglitazone 45 mg once daily.
Other diabetes-related history
The patient monitors blood glucose values 3 times weekly at alternating times and experiences no hyperglycemia or hypoglycemia. He eats a healthy diet, watches the amount of sugar consumed, and is motivated to continue daily exercise to continue to lose weight.
Laboratory values prior to admission
- A1c: 6.3%, 1 month prior to admission
- Creatinine is 1.5 mg/dL with eGFR 47 mL/min, 1 month prior to admission
- Alanine aminotransferase (ALT) 24 U/L, 1 month prior to admission
Following right robotic partial nephrectomy surgery, the patient was able to resume a carbohydrate-consistent diet. Per American Diabetes Association Standards of Medical Care in Diabetes (2017), the patient's liraglutide, pioglitazone, and linagliptin use was discontinued during the hospital stay, in favor of using an insulin program that included basal, nutritional, and correction components.
Prior to discharge, a discussion regarding the patient's preadmission program occurred.
At the time of discharge, creatinine was 1.8 mg/dL with eGFR 39 mL/min, so metformin could not be resumed. Resuming metformin at a lower dose (500 mg twice daily) could have been considered had his eGFR been >45 mL/min.