Things We Do For No Reason: Sliding-Scale Insulin as Monotherapy for Glycemic Control in Hospitalized Patients

Uncertain or interrupted alimentation status or stress hyperglycemia may complicate the assessment of a patient’s insulin needs. One of the insights from the RABBIT 2 surgery trial is that even with interrupted alimentation, patients on a weight-based, long-acting insulin regimen did not experience severe hypoglycemia. Nevertheless, if a patient without type 1 diabetes is felt to be at high risk for a severe hypoglycemic event, it may be prudent to withhold long-acting insulin. However, in that situation, adding SSI to finger-stick monitoring is unlikely to be beneficial. Cases of stress hyperglycemia in nondiabetics can also be challenging, as the persistence of hyperglycemia can be difficult to predict. Guidelines state that if hyperglycemia is persistent, then insulin therapy should be initiated and that this therapy is best accomplished in the form of a basal-prandial regimen.¹⁷

Current guidelines from the American Diabetes Association¹⁷ and the American Association of Clinical Endocrinologists¹⁸ for hospitalized patients with hyperglycemia who require insulin recommend against the prolonged use of SSI as monotherapy (category A recommendation) and support the use of basal plus correctional insulin with the addition of nutritional insulin for patients with consistent oral intake (category A recommendation). Although a complete discourse on the determination of the appropriate starting dose of insulin is outside of the scope of this cas presentation, the basic approach begins with calculating a weight-based total daily dose of insulin, approximately half of which can be given as basal insulin with the remainder given with meals along with correctional insulin as needed to account for premeal hyperglycemia.⁴ For example, the protocol used in the RABBIT 2 trial, which involved known type 2 diabetics, started insulin based on a total daily dose of 0.4 units/kg for patients presenting with blood sugar levels ≤200 mg/dL and 0.5 units/kg for those with higher initial glucose levels.⁷ Half of the total daily dose was given as basal insulin, and the other half was divided among meals. Caution with insulin dosing may be required in patients aged >70 years, in those with impaired renal function, and in situations in which steroid doses are fluctuating. The Society of Hospital Medicine has formulated an online subcutaneous insulin order implementation guideline, eQUIPS, that can be a helpful resource to centers that are interested in changing their practice patterns.¹⁹

• Instead of using SSI monotherapy for hospitalized patients who require insulin, add basal and prandial insulin, using a weight-based approach if necessary for insulin-naive patients.
• Engage with leadership at your center to learn how inpatient hyperglycemia protocols and blood sugar management teams can help provide evidence-based and individualized treatment plans for your patients.
• If no infrastructure exists at your center, the Society of Hospital Medicine offers training and guidance through its eQUIPS inpatient hyperglycemia management program.

In the case presentation, the hyperglycemic patient whose metformin was on hold should have been started on a combination of basal and prandial insulin as determined by his weight and current renal function as opposed to monotherapy with SSI. Using SSI as monotherapy for hyperglycemia is a common practice, and although well-intentioned, it is an ineffective and possibly dangerous approach. Continued efforts must be made to address the gap between guidelines and suboptimal practice patterns locally and nationally.