INTRODUCTION
pneumonia, asthma, COPD
ADVERSE REACTIONS, PNEUMONIA, POSITIVE, CHRONIC OBSTRUCTIVE PULMONARY DISEASE, DISEASE, COPD, ASTHMA, OSTEOPOROSIS
Chronic obstructive pulmonary disease (COPD) is a common and high‐incidence disease affecting the respiratory system. At present, the prevalence rate of COPD among people over 40 years old in China is 13.7%,Bronchodilators and corticosteroids are the primary drugs used for the treatment of COPD at the acute exacerbation and stable stages, and they can be used independently or in combination. However, some patients have low sensitivity to corticosteroid therapy, meaning that using high doses can lead to decreased sensitivity and adverse reactions such as pneumonia and osteoporosis.Theophylline has been used in the treatment of COPD and asthma since 1937; however, because of the narrow safety treatment window, the GOLD Management Strategy guidelines recommended that it should only be used in patients who do not benefit from other bronchodilators and cannot afford treatment.The objective of this study was to compare the effectiveness of doxofylline in reducing severe acute exacerbation and improving long‐term prognosis in different clinical subtypes of COPD and to explore whether it can be used as an adjuvant for standard COPD treatments. Positive findings would indicate clinical and economic benefits for patients who cannot get enough control from other treatment options and find it difficult to use inhaled medicine and would provide a reference basis for the control of treatment drugs in the stable phase of COPD.