Impact of body mass index on efficacy and safety of ticagrelor versus clopidogrel in patients with minor stroke or transient ischemic attack

BACKGROUND: Body mass index (BMI) may affect the response to platelet P2Y(12) receptor inhibitors. We aimed to explore whether BMI influenced the efficacy and safety of ticagrelor and clopidogrel for secondary prevention of minor ischemic stroke or transient ischemic attack (TIA) among patients enrolled in the CHANCE-2 (Ticagrelor or Clopidogrel with Aspirin in High-Risk Patients with Acute Nondisabling Cerebrovascular Events II) trial. METHODS: In a multicentre, randomized, double-blind, placebo-controlled trial, conducted in China, we randomized patients with minor stroke or TIA who carried the CYP2C19 loss-of-function allele to receive either ticagrelor–acetylsalicylic acid (ASA) or clopidogrel–ASA. We classified patients into obese (BMI ≥ 28) or nonobese (BMI < 28) groups. The primary efficacy outcome was stroke within 90 days, and the primary safety outcome was severe or moderate bleeding within 90 days. RESULTS: Among 6412 patients, 876 were classified as obese and 5536 were classified as nonobese. Compared with clopidogrel–ASA, ticagrelor–ASA was associated with a significantly lower rate of stroke within 90 days among patients with obesity (25 [5.4%] v. 47 [11.3%]; hazard ratio [HR] 0.51, 95% confidence interval [CI] 0.30–0.87), but not among those in the nonobese group (166 [6.0%] v. 196 [7.0%]; HR 0.84, 95% CI 0.69–1.04) The interaction of treatment and BMI group was significant (p for interaction = 0.04). We did not observe any difference by BMI group in rates of severe or moderate bleeding (9 [0.3%] v. 10 [0.4%] in the nonobese group; 0 [0.0%] v. 1 [0.2%] in the obese group; p for interaction = 0.99). INTERPRETATION: In this secondary analysis of a randomized controlled trial involving patients with minor ischemic stroke or TIA, compared with clopidogrel–ASA, patients with obesity received more clinical benefit from ticagrelor–ASA therapy than those without obesity. TRIAL REGISTRATION: Clinicaltrials.gov, no. NCT04078737.