Fig. 2
Relationship between serum TNC and periostin levels. a Receiver operating characteristic (ROC) curve for serum TNC levels comparing the GINA step 4 + 5 group with the GINA step 1–3 group. Using Youden’s index, the cut-off value for TNC of 37.16 ng/mL (sensitivity, 51.9%; specificity, 77.8%) is indicated with an arrow. b There was no correlation between serum periostin and TNC levels (rs = 0.111, P = 0.216). Asthmatic patients were divided into four groups according to the cut-off values for serum TNC levels (37.16 ng/mL) and serum periostin levels (95 ng/mL)