Diabetes Mellitus: Outpatient Insulin Therapy

Insulin Indication: Patients with DM-2 with HbA1c >10% or on 3 medicines with HbA1c > goal on 2 occasions, 3 months apart 

HbA1C goal- Generally < 7%, but consider < 8% if old age, decreased life expectancy, risk of hypoglycemia  

Initiation

- Start basal insulin ( 0.1-0.2 mg/kg/day ), safe to start Glargine 10 units HS, increase by 2 units every 3rd night until Fasting Blood sugar < 130 mg/dl

The patient can be started with basal insulin 20 units if BMI > 30 and all blood sugars > 200 mg/dl

( Continue Metformin or other agents based on cost, complexity )

If basal insulin required is > 0.5 units/kg/day,  or HbA1C > goal and postprandial hyperglycemia despite fasting sugar at goal,  

1. Add 1 rapid acting insulin injection before largest meal: 4 units insulin/meal, increase by 2 units   every 3rd day until postprandial blood glucose < 180 mg/dl. ( Discontinue sulfonylurea before starting prandial insulin ). Add prandial glucose before all meals if not controlled.

OR 

2. Change to premixed insulin twice daily. 70/30 (Premixed 70% NPH/30% regular insulin before breakfast ( 2/3rd total current basal dose) plus 70/30 before dinner ( 1/3rd current basal dose). Increase by 2 units every 3rd day until blood glucose target is reached.

Insulin Troubleshooting

a. If fasting BG is increased, increase Glargine or evening NPH, consider checking 2 am blood glucose to rule out overnight hypoglycemia

b. If Prelunch  glucose increased, add or increase breakfast insulin

c. If Predinner glucose increased, add or increase AM NPH or lunchtime insulin

 

Note: Self Monitoring of blood glucose is advised. All patients should be educated about the symptoms and self-treatment of hypoglycemia. The ADA recommends the following: (1) check the blood glucose level if signs or symptoms of hypoglycemia are present; (2) if the blood glucose level is less than 70 mg per dL, treat with 15 g of fast-acting carbohydrate, such as 120 ml of fruit juice or three or four glucose tablets; and (3) recheck the blood glucose level after 15 minutes to ensure that it has normalized

 

References:

1. Thompson Amanda et al. Am Fam Physician. 2018 Jan 1;97(1):29-37

2. The Massachusetts General Hospital Handbook of Primary Care. Pocket book. 2nd Edition