Peter M Hannon, MD

Rozanski M, Richter TB, Grittner U, Endres M, Fiebach JB, and Jungehulsing GJ. Elevated Levels of Hemoglobin A1c Are Associated With Cerebral White Matter Disease in Patients With Stroke. Stroke. 2014

“Patchy, nonspecific T2/FLAIR hyperintense white matter disease that is greater than expected for age.” These words, or something similar grace many an MRI read.  A number of studies have found consistent correlations between white matter disease (WMD),  age and HTN, however there has been inconsistent or even contradictory correlations between WMD and other factors such as DM, HL, smoking and renal function.   In this study, Rozanski et al found that in patients with first acute ischemic stroke (AIS), WMD was significantly associated with age, HTN and higher levels of HbA1c, but not elevated levels of TG, LDL, or total cholesterol.

512 patients with first AIS were enrolled in the study.  Standard screening labs were drawn at admission, and fasting lipids and HbA1c on day 2. The mean age was 68.5, 37% were women, and the median NIHSS was 3.  MRI imaging was performed during workup, and WMD burden was measured utilizing the Wahlund score (WS).  Of all patients, 77% had HTN, 49.5% had HL, 24% had AFib and 23% had DM.

Per the authors, this is the first study that they know of that shows a correlation between elevated HbA1c and WMD burden. Median levels of HbA1c were 5.7 to 5.9% in patients with any sign of WMD, vs. 5.3% in patients without hyperintensities.  Interestingly, DM alone did not correlate as strongly, which the authors felt may be explained by the fact that patients diagnosed with DM may be under better control, thus have lower HbA1c’s.

WMD has gained interest in the potential role it may play in cognitive decline and as a risk factor in stroke, and by all accounts appears related to ongoing microvascular damage. This study reaffirms the role of age and HTN play in the process, but in this case at least, also points to elevated HbA1c as another key causative factor—even independent of a diagnosis of DM.
  All this underscores, yet again, the critical importance of risk factor monitoring and management, hopefully long before a first AIS.