Abstract: This review examined four trials lasting 24 to 52 weeks involving 2250 people randomised to either insulin detemir or glargine. Overall, risk of bias of the evaluated studies was high. Insulin glargine was dosed once-daily in the evening. Insulin detemir was initiated once-daily in the evening with the option of an additional dose in the morning in three studies and initiated twice-daily in one study. Of randomised patients 13.6% to 57.2% were injecting insulin detemir twice-daily at the end of trial. Glycaemic control, measured by glycosylated haemoglobin A1c (HbA1c) and HbA1c equal to or less than 7% with or without hypoglycaemia, did not differ statistically significantly between treatment groups. The results showed no significant differences in overall, nocturnal and severe hypoglycaemia between treatment groups. Insulin detemir was associated with less weight gain. Treatment with insulin glargine resulted in a lower daily basal insulin dose and a lower number of injection site reactions. There was no significant difference in the variability of FPG or glucose values in 24-hour profiles between treatment groups. It was not possible to draw conclusions on quality of life, costs or mortality. Only one trial reported results on health-related quality of life and showed no significant differences between treatment groups. Our analyses suggest that there is no clinically relevant difference in efficacy or safety between insulin detemir and insulin glargine for targeting hyperglycaemia. However, to achieve the same glycaemic control insulin detemir was often injected twice-daily in a higher dose but with less weight gain, while insulin glargine was injected once-daily, with somewhat fewer injection site reactions.

Plain-language summary: Four studies investigated a total of 2250 people. Trials lasted between 24 and 52 weeks. Overall, risk of bias of the evaluated studies was high. Our analysis of these intermediate term trials comparing insulin detemir with insulin glargine showed that these two insulins were equally effective in achieving and maintaining glycaemic control (glycosylated haemoglobin A1c (HbA1c)). There were no differences in overall, nocturnal and severe hypoglycaemia when comparing insulin detemir to insulin glargine. Insulin detemir was associated with significantly less weight gain (one study showing a difference of 0.9 kg). Treatment with insulin glargine resulted in a lower daily basal insulin dose and a lower number of injection site reactions (1.8% of patients treated with insulin detemir compared to 0.4% of patients treated with insulin glargine had injection side reactions). There was no difference in the variability of fasting glucose levels or the variability of glucose values of 24-hour profiles between the two treatment groups. From the retrieved trials it was not possible to draw conclusions on the effects of these two insulins on quality of life, their costs or on the number of fatalities. Only one trial reported results on health-related quality of life and showed no significant differences between treatment groups. Our analyses suggest that there is no clinically relevant difference in the efficacy or the safety between the use of insulin detemir and insulin glargine for treating type 2 diabetes mellitus. However, to achieve the same glycaemic control insulin detemir was often injected twice-daily in a higher dose but with less weight gain, while insulin glargine was only injected once-daily, with somewhat fewer injection site reactions.