How to manage blood glucose levels with a sliding scale approach in a patient with type 2 diabetes in a resource-poor area?

Managing Blood Glucose with Sliding Scale Insulin in Resource-Poor Settings

Direct Recommendation

Do not use sliding scale insulin (SSI) as the sole approach for managing diabetes in resource-poor settings; instead, use human insulin in a basal-bolus regimen with metformin and/or sulfonylureas as the foundation of treatment. 1

Why Sliding Scale Insulin Should Be Avoided

Evidence Against SSI

• Sliding scale insulin has been used for over 80 years without evidence supporting its use as standard of care, and multiple studies reveal poor glycemic control and deleterious effects. 2

• SSI is a reactive rather than proactive approach that fails to prevent hyperglycemia and does not address the underlying insulin requirements of patients with diabetes. 3

• A Cochrane systematic review of 8 trials (1,048 participants) found that SSI resulted in mean blood glucose levels 14.8 mg/dL (0.8 mmol/L) higher compared to basal-bolus insulin regimens (P < 0.001). 4

• The same review found SSI provides no mortality benefit and results in worse glycemic control overall. 4

Recommended Approach for Resource-Poor Settings

First-Line Oral Therapy

• Start with metformin as first-line therapy for all patients with type 2 diabetes unless contraindicated. 1, 5

• Add a sulfonylurea as second-line treatment when metformin alone fails to achieve glycemic control (strong WHO recommendation, moderate-quality evidence). 1

When to Introduce Insulin

• Introduce human insulin (regular and NPH) when oral agents fail to achieve glycemic control with metformin and/or sulfonylurea (strong WHO recommendation). 1

• Human insulin is specifically recommended over expensive insulin analogues in resource-limited settings due to cost considerations, despite analogues having slightly lower hypoglycemia rates. 1

Proper Insulin Regimen Structure

Use a basal-bolus approach, NOT sliding scale:

• Provide approximately 50% of total daily insulin as basal insulin (NPH) and 50% as prandial insulin (regular human insulin before meals). 6

• Typical starting dose is 0.4-1.0 units/kg/day total, with basal insulin titrated to control overnight and fasting glucose levels. 6

• Administer rapid-acting (regular) insulin before meals to control postprandial glucose excursions. 6

Why Basal-Bolus is Superior in Resource-Poor Settings

• Basal-bolus insulin provides proactive glucose control rather than reactive correction. 3

• Human insulin (regular and NPH) is significantly less expensive than insulin analogues while providing adequate glycemic control. 1

• The WHO specifically recommends human insulin for resource-limited settings where patients often pay out-of-pocket for medications. 1

Practical Implementation Algorithm

Step 1: Optimize Oral Medications First

• Ensure metformin is maximized (up to 2,550 mg/day if tolerated). 7
• Add sulfonylurea if metformin alone is insufficient. 1

Step 2: Add Basal Insulin When Needed

• Start NPH insulin at bedtime (0.1-0.2 units/kg) while continuing oral agents. 1
• Titrate based on fasting glucose levels every 2-3 days.

Step 3: Add Prandial Insulin for Full Control

• When basal insulin alone is insufficient, add regular human insulin before meals (starting 4 units per meal or 10% of basal dose). 1
• Adjust doses based on pre-meal and 2-hour post-meal glucose readings.

Step 4: Supplemental Correction Doses

• If correction doses are needed, use them IN ADDITION to scheduled basal-bolus insulin, not as a replacement. 3
• A simple subcutaneous insulin algorithm that adjusts every 4 hours based on both previous dose and current glucose can be effective. 8

Critical Pitfalls to Avoid

• Never use SSI as monotherapy - it leads to persistent hyperglycemia and poor outcomes. 3, 2, 4

• Do not skip basal insulin - without background insulin coverage, patients will have uncontrolled fasting and between-meal glucose levels. 6

• Avoid expensive insulin analogues (glargine, detemir) unless patients have frequent severe hypoglycemia with human insulin, as the cost difference is substantial with minimal clinical benefit in most patients. 1

• Do not use DPP-4 inhibitors, SGLT-2 inhibitors, or GLP-1 agonists as second or third-line agents in resource-poor settings - they cost several times more than human insulin with similar or inferior glucose-lowering effects. 1

When Insulin Analogues May Be Justified

• Consider long-acting insulin analogues (glargine or detemir) only for patients with frequent severe hypoglycemia (blood glucose <40 mg/dL or 2.2 mmol/L) despite optimized human insulin regimens. 1

• This is a weak recommendation with moderate-quality evidence for hypoglycemia reduction but must be balanced against cost in resource-limited settings. 1