What is the recommended approach for initiating basal insulin (e.g. insulin glargine, insulin detemir) therapy in a typical adult patient with type 2 diabetes mellitus?

How to Start Basal Insulin

Start basal insulin at 10 units once daily or 0.1-0.2 units/kg body weight, administered at the same time each day, and titrate by 2-4 units every 3 days until fasting glucose reaches 80-130 mg/dL. 1

Initial Dosing Strategy

• For insulin-naive patients with type 2 diabetes, begin with 10 units once daily OR 0.1-0.2 units/kg body weight, administered subcutaneously at the same time each day 2, 1, 3
• Continue metformin (unless contraindicated) and possibly one additional non-insulin agent when initiating basal insulin 2, 1
• For patients with severe hyperglycemia (A1C ≥9%, blood glucose ≥300-350 mg/dL, or symptomatic/catabolic features), consider higher starting doses of 0.3-0.5 units/kg/day as total daily insulin using a basal-bolus regimen from the outset 1

Titration Algorithm

• Increase basal insulin by 2 units every 3 days if fasting glucose is 140-179 mg/dL 1
• Increase basal insulin by 4 units every 3 days if fasting glucose is ≥180 mg/dL 1
• Target fasting plasma glucose: 80-130 mg/dL 2, 1
• If hypoglycemia occurs without clear cause, reduce the dose by 10-20% immediately 1

Administration Guidelines

• Administer subcutaneously into the abdominal area, thigh, or deltoid once daily at any time of day, but at the same time every day 3
• Do not dilute or mix insulin glargine with any other insulin or solution 3
• Rotate injection sites to reduce risk of lipodystrophy and localized cutaneous amyloidosis 3

Patient Education Essentials

• Instruct patients in self-titration of insulin doses based on daily fasting glucose monitoring, as this improves glycemic control 2
• Provide comprehensive education on self-monitoring of blood glucose, hypoglycemia recognition and treatment, proper injection technique, and site rotation 1
• Teach "sick day" management rules and insulin storage/handling 1

Critical Threshold: When to Stop Escalating Basal Insulin Alone

• When basal insulin exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day, add prandial insulin rather than continuing to escalate basal insulin alone 2, 1, 4
• Clinical signals of "overbasalization" include: basal dose >0.5 units/kg/day, bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia episodes, and high glucose variability 1
• If after 3-6 months of basal insulin optimization, fasting glucose reaches target but HbA1c remains above goal, add prandial insulin starting with 4 units before the largest meal or 10% of the basal dose 1

Common Pitfalls to Avoid

• Never delay insulin initiation in patients not achieving glycemic goals with oral medications, as this prolongs hyperglycemia exposure and increases complication risk 1
• Never discontinue metformin when starting insulin unless contraindicated, as the combination provides superior glycemic control with reduced insulin requirements and less weight gain 1
• Avoid continuing to escalate basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia, as this leads to overbasalization with increased hypoglycemia risk and suboptimal control 1, 4
• Do not use sliding scale insulin as monotherapy; scheduled basal insulin with correction doses as adjunct only is superior 1

Monitoring Requirements

• Daily fasting blood glucose monitoring is essential during the titration phase 1
• Reassess adequacy of insulin dose at every clinical visit, looking for signs of overbasalization 1
• Check HbA1c every 3 months during intensive titration 1