Effect of various antimicrobial regimens on the clinical course of exacerbations of chronic bronchitis and chronic obstructive pulmonary disease in primary care

Aim: To assess whether the empirical administration of different antibiotics for exacerbations of chronic bronchitis and chronic obstructive pulmonary disease (COPD) in the primary-care setting is associated with a different clinical course, principally related to the speed of onset of action. Design and setting: Observational, non-randomised, open-label study carried out between February 2001 and May 2002 in 252 primary-care practices in Spain. Participants: The study included patients diagnosed with an exacerbation of chronic bronchitis or COPD. Information was requested on the first ten patients attending each clinic with a diagnosis of exacerbation of their chronic bronchitis or COPD within the study dates. All patients were followed up for 30 days, with an intermediate visit at 10 days at which they were asked about the duration of the symptoms; the presence of symptoms was assessed at 3, 5 and 10 days. Three antibiotic regimens were evaluated: amoxicillin 500mg plus clavulanic acid 125mg (co-amoxiclav) three times daily for 10 days, clarithromycin 500mg twice daily for 10 days, and moxifloxacin 400mg once daily for 5 days. Results: 252 general practitioners participated in the study, registering 1456 patients who met inclusion criteria. The clinical cure rate, defined as the remission of the three cardinal symptoms of exacerbation (increased expectoration, change in sputum purulence, and increased dyspnoea) were similar on the tenth day: 67% in the group receiving moxifloxacin, 65% in those taking co-amoxiclav, and 64% in those taking clarithromycin (p = 0.38). However, differences in the clinical cure rates were observed on day 3 (moxifloxacin 20%, co-amoxiclav 9.6%, and clarithromycin 6.5%) and day 5 (moxifloxacin 49%, co-amoxiclav 26.5% and clarithromycin 30%). The cure rates were significantly higher in the moxifloxacin group than in either of the other two treatment groups (p < 0.001 for both days). Conclusions: The aim of antimicrobial therapy should be to reduce both the rate of therapeutic failure and the duration of symptoms. Even though the clinical cure rates in this study were similar at 10 days, the time to resolution of symptoms was shorter in the patients in the moxifloxacin group than in the other two groups.