All the subjects will experience the follow-up every six months, accompanying the monitoring of fast blood glucose (FBG). The complete follow-up will span three years. The follow-up for one patient will stop early when its FBG≥7.0mmol/L which indicates the patient has developed new T2DM.
The subjects will be divided into two groups according to whether patients develop T2DM at the end of each follow-up, namely, COPD patients with T2DM and COPD patients without T2DM
