Issue 105 Item 15 Hyperglycemia May Raise Stroke Risk, Results from Three Studie

Hyperglycemia may make people more susceptible to strokes and appear to worsen the outcomes of stroke patients after thrombolytic therapy. Findings from three separate studies presented at the 27th International Stroke Conference implicated insulin resistance in people without frank diabetes as a major risk factor for cerebrovascular disease.

“Patients with established cerebrovascular disease may be candidates for treatment with a drug that raises insulin sensitivity,” Dr. Walter N. Kernan of Yale University, New Haven, said while presenting a poster at the conference.

The study done by Dr. Kernan and his associates focused on 174 patients who were hospitalized with an ischemic stroke or a transient ischemic attack (TIA) at one of three hospitals from July 2000 through June 2001. The patients were offered an oral glucose tolerance test 2-6 months after their cerebrovascular event; 72 agreed to participate. The index event was stroke in 79%, and a TIA in 21%. The fasting serum glucose level was normal (less than 110 mg/dL) in 58% and impaired (111-125 mg/dL) in 14%, but none of the patients had frank diabetes (a fasting serum glucose level of 126 mg/dL or higher).

Insulin resistance was found in half of the nondiabetic patients with a recent history of stroke or TIA. Patients with insulin resistance were younger and had worse stroke outcomes.

A study at Yale looked at the prevalence of hyperglycemia in nondiabetic stroke patients. A chart review was done for 119 patients at 10 community or acute care hospitals from May 1996 through December 1998.

There was no history of diabetes in 93 patients, yet 5 had a maximum serum glucose level greater than 200 mg/dL, and 28 (30%) had a maximum serum glucose level greater than 140 mg/dL, which is considered to be hyperglycemia, said Dr. Dawn M. Bravata of Yale. Only 1 of the 28 patients with hyperglycemia underwent further testing for diabetes or hyperglycemia.

In a third poster, London (Ont.) Health Sciences Centre researchers studied 119 acute ischemic stroke patients treated with tissue plasminogen activator (tPA); 37 had serum glucose values of 150 mg/dL or greater. Response to thrombolysis was not affected by hyperglycemia, said Dr. Arturo Tamayo of the centre. Mortality at 3 months, however, was 36% in the hyperglycemic patients and 8% in those with normal serum glucose levels. Of those who survived 3 months, stroke score improved in 54% with hyperglycemia and 79% with normal values. Internal Medicine News May 1 2002 • Volume 35 • Number 9