Platelet count as a potential predictor in refractory Takayasu arteritis

Platelet parameters have been recognized as important markers for disease severity in various types of diseases. The aim of our study was to investigate whether platelet count could be used as a potential predictor of refractory Takayasu arteritis (TAK). In this retrospective study, fifty-seven patients were selected as development data group to identify the associated risk factors and potential predictors of refractory TAK. Ninety-two TAK patients were included in the validation data group to verify the predictive value of platelet count for refractory TAK. Refractory TAK patients had higher levels of platelet (PLT) than non-refractory TAK patients (305.5 vs. 272.0 × 10⁹/L, P = 0.043). For PLT, the best cut-off value was 296.5 × 10⁹/L to predict refractory TAK. Elevated PLT (> 296.5 × 10⁹/L) was found to be statistically related to refractory TAK (OR [95%CI] 4.000 [1.233-12.974], p = 0.021). In the validation data group, the proportion of refractory TAK in patients with elevated PLT was significantly higher than that in patients with non-elevated PLT (55.6% vs. 32.2%, P = 0.037). The 1-, 3- and 5-year cumulative incidence of refractory TAK were 37.0%, 44.4% and 55.6% in patients with elevated PLT, respectively. Elevated PLT (p = 0.035, hazard ratio (HR) 2.106) was identified as a potential predictor of refractory TAK. Clinicians should pay close attention to platelet levels in patients with TAK. For TAK patients with PLT greater than 296.5 × 10⁹/L, closer monitoring of the disease and comprehensive assessment of disease activity are recommended to be alert to the occurrence of refractory TAK.