What is the recommended initial insulin regimen for a patient requiring sliding scale insulin (SSI) therapy, considering their blood glucose levels and overall health status, including any comorbidities such as impaired renal function or heart failure?

Sliding Scale Insulin Should Be Strongly Avoided as Monotherapy in Hospitalized Patients

Sliding scale insulin (SSI) alone is explicitly condemned by all major diabetes guidelines and should not be used as the sole insulin regimen for hospitalized patients with diabetes. 1, 2 Instead, a scheduled basal-bolus insulin regimen is the preferred approach for achieving glycemic control while minimizing complications. 1, 2

Why SSI Alone Fails

SSI treats hyperglycemia reactively after it occurs rather than preventing it, leading to dangerous glucose fluctuations that exacerbate both hyper- and hypoglycemia. 2, 3 This reactive approach results in:

• Poor glycemic control: Only 38% of patients on SSI alone achieve target glucose control (<140 mg/dL) compared to 68% with basal-bolus regimens 2, 4
• Persistent hyperglycemia: SSI injections result in subtherapeutic effects 84% of the time, with glucose levels remaining elevated despite treatment 3
• Increased complications: SSI is associated with higher rates of postoperative wound infections, prolonged hospital stays, and poor wound healing 2, 4

The Recommended Approach: Basal-Bolus Insulin Regimen

Initial Dosing Algorithm

For insulin-naive or low-dose patients:

• Start with 0.3-0.5 units/kg/day total daily dose 1, 2
• Split as 50% basal insulin (given once daily) and 50% prandial insulin (divided before meals) 1, 2
• Example: For a 70 kg patient = 21-35 units total daily dose → 10.5-17.5 units basal + 10.5-17.5 units prandial (split among 3 meals)

For high-risk patients (elderly >65 years, renal failure, poor oral intake):

• Use lower doses of 0.1-0.25 units/kg/day 1, 2
• Primarily as basal insulin with correction doses only 2

For patients on high home insulin doses (≥0.6 units/kg/day):

• Reduce total daily dose by 20% during hospitalization to prevent hypoglycemia 1, 2

Target Glucose Ranges

• Non-critically ill patients: 140-180 mg/dL 1
• Initiate insulin therapy when glucose persistently exceeds 180 mg/dL (checked on two occasions) 1
• More stringent goals of 110-140 mg/dL may be appropriate for selected patients if achievable without significant hypoglycemia 1

When SSI Might Be Acceptable (Limited Scenarios)

SSI as monotherapy might be acceptable only in these specific situations: 2

• Patients with mild stress hyperglycemia without pre-existing diabetes
• Patients with well-controlled diabetes (HbA1c <7%) on minimal home therapy who develop mild hyperglycemia during hospitalization
• Patients who are NPO with no nutritional replacement and only mild hyperglycemia
• Patients who are new to steroids or tapering steroids

Critical Pitfalls to Avoid

Never use SSI alone for type 1 diabetes – this is dangerous and can lead to diabetic ketoacidosis 1, 2

Never continue the same SSI regimen throughout hospitalization without modification despite poor control – this occurs in 81% of patients and perpetuates inadequate glycemic management 3

Never rely solely on correction doses – scheduled basal insulin provides the foundation, with correction doses serving only as adjuncts 1, 2

Avoid premixed insulin (70/30) in hospitals – this has been associated with unacceptably high rates of hypoglycemia 1, 2

Monitoring Requirements

• Point-of-care glucose testing before each meal and at bedtime for patients eating regular meals 1
• Every 4-6 hours for patients with poor oral intake or NPO 1
• If correction doses are frequently required, increase the scheduled insulin doses accordingly 2

Evidence Supporting Basal-Bolus Over SSI

Randomized trials consistently demonstrate that basal-bolus insulin regimens achieve superior outcomes: 2, 4

• Better glycemic control: Mean blood glucose 157 mg/dL with basal-bolus vs. higher levels with SSI alone
• Reduced complications: Lower rates of postoperative wound infections and acute renal failure
• Similar hypoglycemia rates: Despite better control, severe hypoglycemia rates are comparable (approximately 2.4% with basal-bolus) 4

The evidence is clear: scheduled basal-bolus insulin regimens should replace SSI monotherapy as the standard of care for hospitalized patients with diabetes. 1, 2