BackgroundThe implication of the monocyte-to-high-density lipoprotein ratio (MHR) in Takayasu arteritis (TAK) remains unclear.ObjectiveWe aimed to assess the predictive value of the MHR to identify coronary involvement with TAK and determine the patient prognosis.MethodsIn this retrospective study, 1,184 consecutive patients with TAK were collected and assessed, and those who were initially treated and with coronary angiography were enrolled and classified according to coronary involvement or no involvement. Binary logistic analysis was performed to assess coronary involvement risk factors. Receiver-operating characteristic analysis was used to determine the MHR value to predict coronary involvement in TAK. Major adverse cardiovascular events (MACEs) were recorded in patients with TAK and coronary involvement within a 1-year follow-up, and Kaplan–Meier survival curve analysis was conducted to compare MACEs between them stratified by the MHR.ResultsA total of 115 patients with TAK were included in this study, and 41 of them had coronary involvement. A higher MHR was found for TAK with coronary involvement than for TAK without coronary involvement (P= 0.014). Multivariate analysis showed that the MHR is an independent risk factor for coronary involvement in TAK (odds ratio: 92.718, 95% confidence interval (CI): 2.813–3056.291,P =0.011). With the best cut-off value of 0.35, the MHR identified coronary involvement with 53.7% sensitivity and 68.9% specificity [area under the curve (AUC): 0.639, 95%CI: 0.544–0.726,P=0.010] and identified left main disease and/or three-vessel disease (LMD/3VD) with 70.6% sensitivity and 66.3% specificity (AUC: 0.704, 95%CI: 0.612–0.786,P =0.003) in TAK. Combined with other variables, the MHR identified coronary involvement with 63.4% sensitivity and 90.5% specificity (AUC: 0.852, 95%CI: 0.773–0.911,P< 0.001), and identified LMD/3VD with 82.4% sensitivity and 78.6% specificity (AUC: 0.827, 95%CI: 0.720–0.934,P< 0.001) in TAK. A total of 39 patients with TAK and coronary involvement were followed up for 1 year, and 5 patients suffered a MACE. Those with an MHR >0.35 had a higher MACE incidence than their counterparts with an MHR ≤0.35 (χ2=4.757,P= 0.029).ConclusionsThe MHR could be a simple, practical biomarker for identifying coronary involvement and LMD/3VD in TAK and predicting a long-term prognosis.