[Theophylline in the treatment of chronic obstructive pulmonary disease: a randomized, double-blind, placebo-controlled study].

OBJECTIVE: To observe the benefits and safety of low-dose, slow-release oral theophylline for long-term treatment of stable chronic obstructive pulmonary disease (COPD). METHODS: This was a randomized, parallel-group, double-blind, placebo-controlled trial. Slow-release theophylline (200 mg/d) twice daily or placebo (matching theophylline) was randomly given to 110 patients with stable COPD in the rural area of Shaoguan, Guangdong Province, for one year. Efficacy measures were spirometry and exacerbations, quality of life, dyspnea scores, satisfaction with treatments and adverse effects. Comparison of benefits was performed using superiority test. RESULTS: Of 110 patients, 85 (42 subjects in theophylline group and 43 subjects in placebo group) completed the study. An analysis for intention-to-treat (ITT) individuals showed that individuals with the treatment of theophylline experienced statistically fewer numbers [(0.8 +/- 1.2) times/year, (1.7 +/- 2.6) times/year, Z = -1.674, P = 0.047] and days of exacerbations [(4.6 +/- 7.9) d, (12.5 +/- 22.8) d, Z = -1.699, P = 0.045] in comparison to subjects receiving placebo, that patients receiving theophylline were less likely than the placebo group to experience moderate exacerbations [(0.4 +/- 1.0) times/year, (1.0 +/- 1.8) times/year, Z = -2.136, P = 0.017], and that more individuals satisfied with treatments in the theophylline group than the placebo group (n = 16, 3, Z = -2.198, P = 0.014), and that statistically greater improvement in pre-bronchodilators FEV(1) [(0.006 +/- 0.180) L, (-0.053 +/- 0.169) L, t = 1.789, P = 0.038] were found in the theophylline group in comparison to the placebo group. The similar results were observed in an analysis for per-protocol (PP) subjects. Statistical improvement on quality of life was observed in the PP subjects of theophylline group than in placebo group (-28 +/- 20, -20 +/- 23, F = 2.893, P = 0.047). Time to the first exacerbation in patients receiving theophylline was also delayed in comparison to placebo (365 d, 276 d, chi(2) = 3.880, P = 0.049). But no statistical difference was found between the two groups in post-bronchodilators FEV(1) in both ITT and PP subjects (t = -0.012, P = 0.495 and t = 0.040, P = 0.484 respectively). Drug-related adverse events (8.8%) such as insomnia, palpitation, stomach discomforts or stomachache, and headache were observed in the theophylline group. CONCLUSION: Slow-released oral theophylline (200 mg/d) may be beneficial and safe in long-term treatment of stable COPD in rural area.

[Study on the prevalence rate of chronic obstructive pulmonary disease in northern part of Guangdong province].

OBJECTIVE: To investigate the prevalence of chronic obstructive pulmonary disease (COPD) and its risk factors in population over 40 years old in northern part of Guangdong province. METHODS: Using uniform scheme, procedures and questionnaire, a cluster-randomized-sampling survey for the population aged over 40 years in a rural area of Shaoguan in the northern part of Guangdong province was performed. Spirometry was performed for every participant, followed by a bronchodilatation test when bronchial obstruction was present. RESULTS: There were 1468 cases with complete data from 1498 people aged >or= 40 years including 640 males, 828 females with an average age of 54.3 years old. The total prevalence of COPD was 12.0%. The prevalence of COPD in males was significantly higher than that in females (18.3% vs. 7.1%, P < 0.01). Only 80.7% of the patients with COPD presented one or more symptoms as cough, phlegm, or dyspnoea. Underdiagnosis of COPD would be quite serious. Only 26.1% of the cases was previously diagnosed to have chronic bronchitis, emphysema, or COPD. Smoking was an important risk factor to COPD and 78.4% of the patients with COPD were smokers. However, relation of biomass and COPD called for further investigation. CONCLUSION: Prevalence of COPD was much higher than expected in the northern part of Guangdong while smoking was an most important risk factor of COPD. Lung function test seemed to be of great importance to COPD diagnosis, especially in the earlier period of COPD.