Natural history of asymptomatic cervical internal carotid artery stenosis in diabetes mellitus patients

Diabetes mellitus (DM) is known to be a cause of cervical internal carotid artery stenosis (ICS). In this study, we investigated the natural history of asymptomatic ICS in DM patients without surgical intervention. We conducted a retrospective study of 148 DM patients with asymptomatic ICS treated medically at the Kansai Electric Power Hospital from April 2013 to March 2023, inclusive. We examined the incidence of ischemic stroke with ICS and evaluated the patients’ clinical characteristics and imaging findings. Ischemic stroke with ICS occurred in 7 patients (4.7 %), and only smoking history was significantly correlated with the incidence of ischemic stroke (p = 0.04). The incidence rate of ischemic stroke with ICS in this study (4.7%) was comparable to the previous report. The result that, the correlated factors of the incidence of ischemic stroke in DM patients with ICS was only smoking history, seemed acceptable. However, prospective studies with a larger number of cases may be needed in the future to determine the correlated factors more eligibly.