Patients diagnosed of interstitial lung disease and treating with glucocorticoids could be enrolled in this clinical trial. Those who is in an acute inflammatory phase and diagnosed with hemorrhagic disease should are excluded, so are those unwilling to carry the continuous glucose monitoring (CGM) device. When the dose of prednisolone is applied 15mg per day steadily and is going to be decreased, the CGM is conducted. At the same time, blood tests evaluating the glucose metabolism are measured, including HbA1c, GA, fasting insulin and fasting glucose. After taking 7.5mg prednisolone per day for 3 months, participants do the CGM and blood tests again to evaluate the glucose metabolism during this period. The CGM data could be used for the glucose evaluation, which can manifest the glucose characteristics in the circumstances of glucocorticoid use. By comparing the CGM data and the blood tests, the investigators hope to find the different features of the glucose metabolism due to different doses.