So much of the practice of neurology happens under the shadow of unanswered questions. One such unanswered question is how tightly to regulate blood glucose in the hours and days following acute ischemic stroke. We know that diabetes is associated with poorer outcomes after stroke, but how strict must we be with glucose control? A recent study provides some guidance by comparing the outcomes of more stringent glucose control to standard protocols after stroke. The results are a little surprising.

The SHINE study, published in the July 23, 2019, issue of JAMA, enrolled 1,151 patients, with or without hyperglycemia, within 12 hours of acute ischemic stroke. Patients were randomly assigned to IV insulin with an aggressive target glucose of 80 to 130 mg/dL, or to the more standard sliding scale insulin with target glucose of 80 to 179 mg/dL for up to 72 hours.

Patients were then evaluated after 90 days, with endpoints of disability, neurologic function, and quality of life considered. The 90-day modified Rankin score was used, with scores ranging from 0 (no symptoms) to 6 (death).

The results demonstrated no significant difference between the two groups. At 90 days post-stroke, 20.5 percent of patients receiving intensive glucose control and 21.6 percent of those receiving sliding scale insulin had favorable outcomes, which was not a statistically significant difference. However, the risk of adverse events was higher in the intensive treatment group, with 11.2 percent of the IV insulin group stopping treatment early due to adverse events, compared to 3.2 percent in the standard treatment group. Notably, hypoglycemia only occurred in the intensive treatment group, with 2.6 percent of patients affected.

In addition to the increased risk of adverse events, a higher level of care for patients receiving insulin infusion was needed, requiring more nursing resources than in the sliding scale group.

When an interim analysis revealed that both treatment arms were equally effective, with higher risks in the intensive treatment group, researchers stopped the SHINE study early.

As Karen Johnston, MD, the study’s lead author, explained in an interview at the International Stroke Conference 2019, “These data fill the gap that our stroke community has been concerned about.” She went on to say in a press release that, “We found the extra risks associated with aggressive treatment were not worth it.”

Besides offering a high level of evidence to answer the question about glucose control after stroke, this study serves as an important reminder about all of those unanswered questions—we often find that the answers aren’t quite what we expected.

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