Spotlight on insulin timing

The timing of insulin injections for patients with type 2 diabetes was the focus of several studies published in the past month.

A randomized crossover study assessed whether it is necessary to wait 20 minutes after injecting insulin before eating. The trial, published by Diabetes Care on Jan. 22, included 100 German patients with type 2 diabetes who injected insulin 20 minutes before eating in one phase of the trial and injected insulin immediately before eating in the other phase. Their average hemoglobin A1c (HbA1c) increased by only about 0.08% when they didn't wait to eat, and rates of hypoglycemia were similar. Patients were more satisfied with treatment in the no-wait phase and 86.5% said they preferred it. Researchers noted that the study didn't assess the effects of 30-, 45- or 60-minute waits, but they concluded that a 20-minute interval is not necessary and could potentially reduce the problem of patients forgetting injections.

Another study, published by Diabetes Care on the same day, included about 600 type 2 diabetes patients randomized to once-daily insulin degludec with their evening meal, once-daily insulin glargine at the same time each day, or a pre-set schedule of insulin degludec with large variations in the interval between doses (between 8 and 40 hours). After 26 weeks, HbA1c levels had improved by similar amounts in all three groups, and similar rates of hypoglycemia and adverse events were seen. The highly variable dosing schedule is not recommended for clinical practice, but the study shows that varying the time of injections doesn't compromise glycemic control, the study authors said. This finding may be useful for, and improve compliance by, patients with changing schedules, they suggested.

A third study, published by the new journal The Lancet Diabetes & Endocrinology on Feb. 2, looked at the timing of insulin use in the overall course of diabetes. Researchers conducted a systematic review of seven studies that treated newly diagnosed type 2 patients with intensive insulin therapy. They found that the therapy increased patients' β cell function by 13% and decreased their insulin resistance by 43% (as measured by Homeostasis Model Assessment). Four of the studies assessed diabetes remission rates and found that 42.1% patients were in remission 24 months after therapy. The patients who achieved remission had higher body mass index and lower fasting plasma glucose at baseline, which might present a way to target the insulin strategy at the patients most likely to benefit, the authors said. An accompanying comment noted that all of the studies were conducted in China and Taiwan, so further investigation is warranted before applying the findings to practice in other settings.