Which insulin formulation is appropriate to start for basal coverage in type 1 diabetes?

• A. Insulin glargine
• B. Insulin lispro
• C. Regular insulin
• D. NPH insulin

Answer: (A)

Basal coverage needs a long-acting insulin that provides a steady background level over 24 hours to suppress hepatic glucose production when not eating. Insulin glargine fits this role well because it delivers a relatively flat, prolonged effect with minimal peak, often dosed once daily. This stability helps keep fasting glucose more consistent and reduces the risk of nocturnal hypoglycemia compared with older basal options.

Rapid-acting insulin like lispro is designed for mealtime use; it acts quickly and its effect doesn’t provide the steady background needed for basal control. Regular insulin is short-acting with a more pronounced peak and shorter duration, making it less suitable for continuous basal coverage. NPH is intermediate-acting and has more variable absorption with a clearer peak, which can lead to inconsistent basal control and more hypoglycemia risk.

So, starting with a long-acting basal insulin like glargine provides the appropriate background coverage for type 1 diabetes and fits the basal-bolus strategy.