Leukoaraiosis on MRI in patients with minimally symptomatic obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is associated with hypertension, nocturnal blood pressure (BP) surges, and increased risk of stroke. It may therefore also be associated with a higher risk of developing leukoaraiosis. Only few data about the prevalence of leukoaraiosis in patients with OSA, and any association between degrees of severity of either condition, exist.

We studied patients who were part of a clinical trial (MOSAIC) in minimally symptomatic OSA. All patients had brain MRI (T2, FLAIR) at baseline. A single observer assessed the images for the presence and severity of leukoaraiosis (ARWMC-score). We related the extent of leukoaraiosis to the severity of OSA (measured by oxygen desaturation index [ODI]) and the presence of other vascular risk factors.

183 patients (156 men, 85.2%; mean age ± SD = 57.7 ± 7.4 years; median oxygen desaturation index = 9.6, interquartile range = 4.6-16.0) took part in the study. Although 135 (74%) patients had some leukoaraiosis, this was generally mild. We confirmed the well-known risk factor associations between leukoaraiosis, increasing age (p < 0.0001) and hypertension (p = 0.003), but we did not find any association between OSA and leukoaraiosis (p = 0.33), despite both conditions being associated with increasing current BP and a history of hypertension.

Our data confirm the well-known association between leukoaraiosis, age and increasing BP. However, we found no association between OSA and leukoaraiosis despite some shared risk factor associations. Our findings suggest that OSA is not a strong independent risk factor for leukoaraiosis. Confounding by hypertension may explain any apparent association in previously reported studies of patients with severer OSA.