Optimizing glycemic control without risking hypoglycemia is crucial in toddlers and preschoolers with type 1 diabetes (T1D) to avoid cognitive impairment later in life. Hence, this study aims to compare glycemic parameters among toddlers and preschoolers with T1D in relation to different basal insulins. Sixty toddlers and preschoolers with T1D with mean age of 3.53 ± 1.17 years (range, 2–6) and mean diabetes duration of 9.37 ± 1.85 months were randomly assigned into three equal groups; group A received insulin degludec, group B received insulin glargine, and group C were on NPH. At baseline, the three groups were matched regarding clinical and laboratory parameters (p> 0.05). They were followed up at 3 and 6 months for insulin daily dose (IDD), hypoglycemia and severe-hypoglycemia frequency, and glycated hemoglobin (HbA1c). At the study endpoint, continuous glucose monitoring (CGM) was assessed in a random sample of 10 patients from each group. The mean time in range (TIR) of the studied cohort was 55.07 ± 24.05%, and their mean coefficient of variation (CV) was 42.82 ± 11.69%. The TIR was significantly higher in the degludec group (69.36 ± 18.54) and the glargine group (55.43 ± 26.51) than the NPH group (32.56 ± 9.11),p< 0.001. Meanwhile, the CV was significantly lower in the degludec group (35.12 ± 6.47) than the gargine (44.1 ± 13.13) and the NPH (53.8 ± 7.54) groups,p< 0.001. The insulin degludec and glargine groups had significantly lower HbA1c (p= 0.002), hypoglycemia (p= 0.006), severe hypoglycemia (p= 0.029), and IDD (p= 0.015) than the NPH group.Conclusion: Insulin degludec and glargine resulted in better HbA1c and TIR with reduced hypoglycemia and IDD than NPH among toddlers and preschoolers with T1D. Moreover, CV was lowest in the insulin degludec group.What is Known:• Insulin therapy is the mainstay of T1D management.• Optimal insulin therapy for young children with T1D should provide
effective glycemic.What is New:• Insulin degludec and insulin glargine have better efficacy than NPH insulin among toddlers and preschoolers with T1D in the term of significantly lower
coefficient of variation, HbA1c and IDD and significantly higher time in range.• Insulin degludec and insulin glargine have better safety in the term of
less hypoglycemia and severe hypoglycemia episodes than NPH insulin among toddlers and
preschoolers with T1D.