Abstract Body:
Background and purpose: Intracranial arterial stenosis (ICAS) is an important cause of ischemic stroke and is associated with a poor prognosis. Obesity has been reported to be associated with a more favorable prognosis in patients with coronary heart disease, but its impact on ICAS remains largely unexplored. This study aimed to investigate the association between obesity and prognosis in patients with asymptomatic ICAS.
Methods: This retrospective cohort study included ICAS patients without stroke history, all of whom had been assessed with transcranial Doppler indicating more than 50% stenosis. Participants were categorized into four groups based on their body mass index (BMI): underweight (BMI<18.5 kg/m²), normal weight (18.5≤BMI<24 kg/m²), overweight (24≤BMI<28 kg/m²) and obese (BMI≥28 kg/m²). The primary outcomes were the occurrence of ischemic stroke and the functional outcomes, which were assessed using the modified Rankin Score (mRS). A poor prognosis is defined as an mRS>2. The association between BMI and prognosis of asymptomatic ICAS was investigated by multivariable analysis.
Results: A total of 1248 asymptomatic ICAS patients were included, distributed as follows: 46 underweight, 516 normal weight, 522 overweight, and 164 obese. With a median follow-up of 48 months, the incidence of ischemic stroke was 8.7%, 6.5%, 5% and 1.2% across the underweight, normal weight, overweight, and obese groups, respectively. The poor prognosis rates were 25.6%, 9.5%, 4.7%, and 5.7% in the same respective groups. Multivariable Cox regression analysis revealed that BMI (hazard ratio: 0.87; 95% confidence interval [CI]: 0.79-0.95; p=0.001) was significantly associated with a reduced risk of ischemic stroke, after adjusting for age, sex, cancer status, smoking, alcohol consumption, hypertension, diabetes, hyperlipidemia, cerebral vascular surgery, and the number of ICAS lesions. Logistic regression (odds ratio: 0.85, 95%CI: 0.78 - 0.93, p<0.001) and linear regression (β: -0.03, 95%CI: -0.037 to -0.023, p<0.001) consistently demonstrated a negative correlation between BMI and poor functional outcome after adjustment.
Conclusions: The findings suggest the presence of an obesity paradox among patients with ICAS, where obesity is associated with a reduced risk of ischemic stroke and a more favorable prognosis in asymptomatic ICAS patients.