Aims: Evidence on outcomes of treating type 1 diabetes (T1D) with long-acting basal insulins in low-resourced settings is lacking. This study aimed to evaluate the impact of switching children and youth with T1D in the low-income country of Mali from human insulin via syringe to long-acting biosimilar insulin glargine delivered by reusable pens combined with short-acting insulin via syringe.

Methods: A two-group parallel design randomised trial was conducted enrolling 260 youth aged <25 years, diagnosed with T1D for ≥12 months without prior use of analogue insulin. Youth were randomised 1:1 to either continue receiving current therapy or switch to analogue insulin. The primary outcome was HbA1c, collected at baseline and 3-monthly for 12 months.

Results: Primary outcome data were available for 130 (100%) youth in the intervention group and 128 (98.5%) in the control group. Over the 12-month study period, mean HbA1c decreased from 103 to 65 mmol/mol (11.6%-8.1%) (p < 0.001) in the intervention group and from 101 to 93 mmol/mol (11.4% to 10.7%) in the control group (p < 0.01), an absolute difference of 30 mmol/mol (95% CI: -37, -24) (p < 0.001). The proportion of participants with HbA1c ≥130 mmol/mol (≥14%) decreased from 38.5% to 0% in the intervention group, versus 40.6% to 21.9% in the control group.

Conclusions: Switching to a basal-bolus insulin regimen including biosimilar glargine resulted in marked improvements in HbA1c and diabetic ketoacidosis episodes. With relevant training, resources, and support, use of long-acting analogue insulin for treating T1D in Mali was feasible and acceptable to participants and healthcare professionals.