medwireNews: The optimal glycemic targets in people with diabetes who have had a stroke may vary according to the stroke subtype, a registry study suggests.
The researchers found the optimal glycated hemoglobin (HbA1c) range to be lowest in patients with small vessel occlusion (17.9% of the study cohort), at 6.3–6.9% (45–52 mmol/mol). On either side of this range, the risk for a primary endpoint event (stroke, myocardial infarction, or cardiovascular death) increased significantly.
“Pathologically, the small-vessel occlusion subtype may be considered as a disease entity that is partway between the micro and macrovascular complications of [type 2 diabetes],” say Moon-Ku Han (Seoul National University College of Medicine, Republic of Korea) and co-researchers.
They suggest: “More stringent glucose control may be justified in stroke patients with small vessel occlusion subtype, which is consistent with the current recommendation for preventing the microvascular complications of [diabetes].”
The team’s analysis encompassed 18,567 patients with diabetes who had an ischemic stroke between 2011 and 2019 and were recorded in a prospective, nationwide, multicenter registry. They were a median age of 70 years and 59.5% were men. During 1 year of follow-up, 1437 participants had a primary endpoint event, with 954 of these being a recurrent stroke.
For the 41.2% of participants with a large-artery atherosclerotic stroke, the optimal HbA1c range was rather higher than that for small vessel occlusion, at 6.8% to 7.9% (51–63 mmol/mol), with risk increases seen both above and below this range.
“Ischemic stroke with significant cerebral artery atherosclerosis could be considered as a manifestation of advanced macrovascular complications in which the risk of hypoglycemia outweighs the additional benefit from strict glucose control,” write the researchers in Neurology.
For the 18.3% of participants with cardioembolic stroke, the ideal HbA1c range was 6.3% to 8.5% (45–69 mmol/mol) However, the risk rose only slightly at higher levels whereas it rose steeply for levels below 6.3%, which again suggests “that preventing hypoglycemia may be more important than hyperglycemia control in such patients,” say Han and team.
Despite these strong associations with overall glycemic control, the researchers found that short-term glucose levels also had a significant effect.
For people who had fasting glucose levels at or below 130 mg/dL (7.21 mmol/L) at admission for their stroke, the risk for a primary endpoint event during follow-up increased by a significant 9% for each 1 percentage point increase in HbA1c, but this relationship was not observed in those with higher glucose levels.
This suggests “that the harmful effect of acute hyperglycemia may mitigate the association between high HbA1c and vascular outcome,” say the study authors.
They note that nearly a quarter of their cohort had discordant HbA1c and fasting glucose levels.
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Neurology 2021; doi:10.1212/WNL.0000000000012729