Old and new basal insulin formulations: understanding pharmacodynamics is still relevant in clinical practice.

Long-acting insulin analogues have been developed to mimic the physiology of basal insulin secretion more closely than human insulin formulations (Neutral Protamine Hagedorn, NPH). However, the clinical evidence in favour of analogues is still controversial. Although their major benefit as compared with NPH is a reduction in the hypoglycaemia risk, some cost/effectiveness analyses have not been favourable to analogues, largely because of their higher price. Nevertheless, these new formulations have conquered the insulin market. Human insulin represents currently no more than 20% of market share. Despite (in fact because of) the widespread use of insulin analogues it remains critical to analyse the pharmacodynamics (PD) of basal insulin formulations appropriately to interpret the results of clinical trials correctly. Importantly, these data may help physicians in tailoring insulin therapy to patients' individual needs and, additionally, when clinical evidence is not available, to optimize insulin treatment. For patients at low risk for/from hypoglycaemia, it might be acceptable and also cost-effective not to use long-acting insulin analogues as basal insulin replacement. Conversely, in patients with a higher degree of insulin deficiency and increased risk for hypoglycaemia, analogues are the best option due to their more physiological profile, as has been shown in PD and clinical studies. From this perspective optimizing basal insulin treatment, especially in type 2 diabetes patients who are less prone to hypoglycaemia, would be suitable making significant resources available for other relevant aspects of diabetes care.