Effects of Tiotropium Combined with Theophylline on Stable COPD Patients of Group B, D and its Impact on Small Airway Function: A Randomized Controlled Trial

Abstract

Introduction: Tiotropium bromide has been widely used in clinical practice, while theophylline is another treatment option for chronic obstructive pulmonary disease (COPD). However, only a few relevant studies have investigated the long-term outcomes and efficacy of both in patients with COPD. We evaluated the effects of tiotropium and low-dose theophylline on stable COPD patients of groups B and D. Methods: Eligible participants (n = 170) were randomized and received either tiotropium 18 µg once daily with theophylline 100 mg twice daily (Group I) or tiotropium 18 µg once daily (Group II) for 6 months. COPD assessment test (CAT), modified Medical Research Council (mMRC) dyspnea scores and pulmonary function tests were measured before randomization and during the treatment. Results: After 6 months of treatment, the CAT scores in both groups decreased significantly (11.41 ± 3.56 and 11.08 ± 3.05, p < 0.0001). The changes of CAT (p = 0.028) and mMRC scores (p = 0.049) between the two groups differed after 1 month of treatment. In Group I, forced expiratory flow after 25% of the FVC% predicted (MEF25% pred) was significantly improved after 3 months (4.84 ± 8.73%, p < 0.0001) and 6 months (6.21 ± 8.65%, p < 0.0001). There was a significant difference in small airway function tests (MEF50% pred, MEF25% pred, and MMEF% pred) between the two groups after 6 month of treatment (p = 0.003, p < 0.0001, and p = 0.021, respectively). Conclusions: Tiotropium combined with low-dose theophylline significantly improved the symptoms and general health of patients with stable COPD of groups B and D after 6 months of follow-up. Additionally, this therapy also improved the indicators of small airway function. Trial Registration: Chinese Clinical Trial Registry (Registry ID: ChiCTR1800019027).