Comparison of insulin preparations
From Dr Peter Stella, medical adviser, Novo Nordisk
You highlighted (News, 15 March) the results of a series of scientific papers published in a supplement of Current Medical Research and Opinion comparing treatment of insulin glargine with insulin detemir or insulin NPH from clinical and cost-effectiveness perspectives.You specifically drew attention to one of the conclusions from these studies, which suggests improved outcomes with the use of insulin glargine in type 2 diabetes when compared with insulin detemir. However, this conclusion is drawn from a study with major methodological flaws, thus making the author's conclusions arguable.In general, when a comparison is made between insulin preparations from any perspective (such as efficacy, safety or treatment-related costs) it is of utmost importance to compare identical insulin regimens. In failing to do this, any observed differences could be purely a reflection of distinct patient/ disease characteristics and not a real difference between the features of the insulin products.In this case the authors compared the two preparations without considering the fact that insulin glargine could be more frequently used in combination with oral anti-diabetics in type 2 diabetes – a regimen called basal only therapy (BOT) – while insulin detemir did not have the licence for this indication. Thus insulin detemir could be more often prescribed as part of intensive basal-bolus therapy, as per the licence during the study period.Since BOT is typically used as an initial form of insulin therapy in type 2 diabetes, patients on BOT represent a cohort at a much earlier stage of the disease, while patients on intensive insulin therapy (basal-bolus regimen) generally have a more severe form of type 2 diabetes. Undoubtedly intensive insulin therapy is related with a higher frequency of hypoglycaemic events than more conservative types of insulin regimens, such as premix regimens or BOT.In fact, the authors failed to mention whether there was any difference in terms of frequencies of the applied insulin regimens between patients on insulin glargine and insulin detemir, therefore the revealed difference in hypoglycaemic risk reduction could rather reflect distinction between insulin glargine and insulin detemir in type 2 diabetes.Furthermore, the authors did not analyse the hypo results separately for patients with type 1 and type 2 diabetes.You also quoted one of the authors highlighting the cost-effectiveness of insulin glargine treatment when compared with treatment with insulin detemir or insulin NPH. Again, fair comparisons should compare like with like, therefore, due to the above detailed flaw, we would argue the relevance of cost-effectiveness conclusions from the study.