Spotlight on insulin formulations

Two papers published in the past month compared human and analog insulins, while another looked at the advantages and disadvantages of inhaled insulin.


Two papers published in the past month compared human and analog insulins, while another looked at the advantages and disadvantages of inhaled insulin.

Long-acting analog insulin, human neutral protamine Hagedorn (NPH) insulin, and premixed insulin were compared in a retrospective cohort study of 21,501 type 2 diabetes patients in Germany who started insulin between 2004 and 2009. Adjusted results, published by Diabetes, Obesity and Metabolism on Aug. 17, showed that patients on analog or NPH insulin had similar rates of acute myocardial infarction (MI). Premixed insulin was associated with a higher risk for MI in the primary analysis but not in a propensity-score matched analysis. These results differ from a previous cohort study, which found an increased risk of MI with NPH insulin, the authors noted. They concluded that none of the studied types of insulin appeared to be associated with increased risk of MI but called for additional studies with longer follow-up.

Analog and regular insulins do differ substantially in cost, according to a viewpoint published in the Aug. 18 Journal of the American Medical Association. Use of analog insulin among privately insured type 2 diabetics has increased from 19% of those taking insulin in 2000 to 96% in 2010, the authors reported. Yet “data suggest that in type 2 diabetes, there is little clinical benefit to using insulin analog compared with regular human insulin and NPH,” the viewpoint said. The authors called for clinicians to “help patients achieve adequate glycemic control at a more reasonable cost” by using older insulins, and they offered advice on transitioning patients from one type to the other.

Inhaled insulin was the focus of a systematic review and meta-analysis, published by The Lancet Diabetes & Endocrinology on Sept. 2. Looking at 12 studies with more than 5,000 patients comparing subcutaneous and inhaled insulin, the researchers concluded that inhaled insulin was associated with less decrease in HbA1c (net difference, 0.16%) but less weight gain (net difference, 1.1 kg) and lower risk of severe hypoglycemia (odds ratio, 0.61). Patients on inhaled insulin were more likely to have mild transient cough (odds ratio, 7.82) and decrease in forced expiratory volume in 1 s (net difference, 0.038 L). The authors concluded that “inhaled insulin should be reserved for healthy adults with diabetes who do not have pulmonary disease and who would otherwise delay initiating or intensifying insulin therapy because they are unwilling or unable to use injectable insulin.” An accompanying comment noted that concerns remain about toxic effects with inhaled insulin and more research is needed.