Insulin pumps with a sensor and threshold-suspend reduced nocturnal hypoglycemia in type 1 diabetes

Patients with type 1 diabetes and documented nocturnal hypoglycemia who were randomized to receive sensor-enhanced insulin pump therapy with a threshold-suspend feature had reduced nocturnal hypoglycemia and no difference in glycated hemoglobin levels compared to those on sensor-augmented insulin pump therapy alone, a recent study found.

The study was published in the July 18 New England Journal of Medicine. A summary of the study was published in the July ACP DiabetesMonthly. The following commentary by Rozalina McCoy, MD, and Steven Smith, MD, was published in the ACP Journal Club section of the Sept. 17 Annals of Internal Medicine.

Hypoglycemia, particularly nocturnal hypoglycemia, is the most common important adverse effect of diabetes therapy, causing considerable morbidity and occasional mortality. The ASPIRE study examined the effect of nocturnal sensor-augmented pump devices equipped with an automated insulin suspension feature on the incidence and duration of nocturnal hypoglycemia in adolescents and adults with type 1 diabetes. They found that both were decreased, but not eliminated, without concomitant change in glycated hemoglobin levels compared with standard insulin pumps and continuous glucose monitors.

Although these results are promising, important questions remain. Without a hypoglycemia/suspension alert mechanism, patients may remain unaware of the episode and thus fail to address the cause of hypoglycemia, thereby allowing it to recur. Indeed, despite suspension of insulin release, hypoglycemia persisted 2 hours after suspension (i.e., at time of insulin resumption) in 33% of suspension events. Also, generalizability of the ASPIRE study to clinical practice is uncertain because it excluded patients most likely to benefit from this technology—those with a history of severe hypoglycemia—and relied on a technically trained health care team.

It is important to keep in mind that our primary goal should not be solely hypoglycemia detection and acute management, but rather prevention of hypoglycemia and hyperglycemia. Behavioral assessment and intervention should complement technology, and providers must work with patients to determine why hypoglycemia occurred in the first place, probing for an excessive basal insulin rate, miscalculated prandial insulin dosing, unaccounted for physical activity, or disproportionate insulin correction as a reaction to hyperglycemia. Technology alone is often insufficient.