Objective: To identify risk factors for late recovery and failure after ambulatory treatment of exacerbations of chronic bronchitis (CB) and chronic obstructive pulmonary disease (COPD).
Methods: Observational, non-randomised study of risk factors carried out in 2001 and 2002 in Primary Care practices. Patients aged 40 or older diagnosed with an exacerbation of CB or COPD of probable bacterial etiology were included in the study and followed up for 10 days. Patients were treated with amoxicillin plus clavulanic acid (co-amoxiclav) 500-125 mg tds for 10 days, clarithromycin 500 mg bd for 10 days or moxifloxacin 400 mg od for 5 days.
Results: Two hundred and fifty-two general practitioners participated, registering 1147 valid patients. The rate of failure at day 10 was 15.1% without significant differences among the antibiotic treatments. Median time to recovery was 5 days. Factors significantly associated with late recovery (>5 days) on multivariate analysis were: use of long-term oxygen (OR=1.96; 95%CI=1.35-2.85); use of short-acting beta-2 agonists (OR=1.51; 1.17-1.92). The use of moxifloxacin had a "protective" effect against late recovery compared to co-amoxiclav (OR=0.34; 0.26-0.45) and clarithromycin (OR=0.41; 0.31-2.85). Factors associated with therapeutic failure were: previous hospitalisation (OR=1.61; 1.08-2.42); and 2 or more exacerbations the previous year (OR=1.51; 1.04-2.17); criteria of CB had a protective effect against failure (OR=0.53; 0.35-0.79).
Conclusions: There are readily identifiable risk factors for ambulatory treatment failure of exacerbations of CB and COPD. In addition, long-term oxygen therapy and short-acting beta-2 agonists are associated with late recovery, and the use of moxifloxacin compared with co-amoxiclav and clarithromycin is associated with faster recovery of symptoms.