CRP and diabetes mellitus: AECOPD patients using in-hospital antibiotics differed from patients not using in-hospital antibiotics regarding patient-related variables (age, BMI, diabetes mellitus, cancer and chronic kidney disease), clinical variables (FEV1% predicted, sputum volume and purulence, body temperature, recent hospitalization and bronchiectasis), treatment-related variables (maintenance inhaled corticosteroids (ICS), theophylline and azithromycin) and laboratory results (CRP levels, peripheral blood leucocyte, neutrophil and eosinophil counts, and arterial blood pH).