BACKGROUND: Factors associated with platelet reactivity (PR) during ticagrelor maintenance dose (MD) are not well defined. We aimed to examine factors that influence levels of PR during chronic ticagrelor therapy. METHODS: We performed individual participant data meta-analysis of 445 patients from 8 studies who had PR assessment with the VerifyNow P2Y12 assay (Accumetrics, Inc, San Diego, CA) while on ticagrelor 90 mg twice a day MD for at least 14 days. RESULTS: Distribution of PR during ticagrelor MD was highly skewed toward lower values. No case of high PR (≥230 P2Y12 reaction units [PRU]) was observed. Age and body mass index (BMI) positively affected PR, with every increase in decade and 5 units of BMI resulting in 7.9% and 4.1% increase in PR, respectively. Current smoking status negatively affected PR with 13.7% decrease in PR in current smokers, compared with nonsmokers. Low PR (LPR) was defined as the lowest quartile of PR values (<10 PRU). In multivariate analysis, diabetes mellitus and age >70 years were independently associated with lower probability for LPR with a relative risk (95% CIs) of 0.570 (0.361-0.899) and 0.554 (0.325-0.944), P = .016 and P = .030, respectively. CONCLUSIONS: Age, BMI, and current smoking status affect PR during ticagrelor MD. Diabetes mellitus and age >70 years were found to be associated with lower probability for LPR. Further research is required to assess the clinical implications of these findings in ticagrelor-treated patients.