Q: Lately, the literature seems to be moving away from the decades-old practice of using a sliding scale for insulin administration. I have not seen updated recommendations on managing a patient newly admitted for diabetes. If a sliding scale is not to be used in this instance, what are the rules of thumb for managing a patient with type 2 diabetes who is admitted to the hospital with high blood sugar levels?
A: The term sliding scale has traditionally been used to denote escalating doses of insulin for patients with escalating blood sugars above 200 mg/dL. In actuality, this is what I like to call a “correction scale” in that it corrects for having taken too little insulin at the previous dosing. What is missing with this approach alone is the realization that all type 1 patients and many type 2 patients will require a basal insulin to prevent fasting hyperglycemia and a prandial insulin dose to cover food intake at mealtimes regardless of premeal glucose level. What has become standard endocrine/diabetes care is to dose insulin with a basal insulin(Glargine, Detemir, or NPH), a prandial dose of fast-acting insulin (Lispro, Aspart, or Glulisine) to cover or match needs from food intake and also use a correction amount. A typical scale would therefore begin with 4 units if blood sugar is <100, 6 units if blood sugar is 100-150, 8 units if blood sugar is 151-200 etc. So the regimen still does adjust (or “slide”) for higher or lower premeal blood sugars but always provides needed fast-acting insulin with food intake. The bedtime scale would include only a “correction” dose of insulin since food intake is minimal at that time of day. It could typically begin with 2 units if the blood sugar is 160-200, 4 units if the blood sugar is 201-240, etc., and can often be used while patients are NPO as well. (See JAMA. 2009;301:213-214.)