Acute exacerbations of chronic bronchitis (AECB), including chronic obstructive pulmonary disease (AECOPD), represent a substantial disease burden to patients, contributing to reduced lung function, increased morbidity and mortality, and long-term impairment in quality of life [1–8].
A role for bacteria is implicated in 40-50% of AECB episodes . In a routine clinical setting, where bacteriological assessment may not be available, empirical antibacterial therapy is generally recommended for patients who fulfill specific clinical criteria, with the aim to influence the disease course and prevent complications [10–12]. Guidelines by Woodhead et al.  recommend antibiotic therapy for patients with increased dyspnea, sputum volume, and sputum purulence (Anthonisen type I) and for patients with two of these symptoms including increased sputum purulence (Anthonisen type II), but not in patients with one of these symptoms alone (Anthonisen type III) . The GOLD recommendations for antibiotic therapy are based on the severity of exacerbations, the presence of risk factors, and predictors of poor outcome (e.g. comorbid conditions, frequency of AECBs, and previous antibiotic use) . Using these criteria, the GOLD guidelines recommend amoxicillin/clavulanate or fluoroquinolones in patients with moderate to severe exacerbations.
Moxifloxacin is a fourth-generation fluoroquinolone with a broad spectrum of activity relevant to the microorganisms isolated in AECB, including Gram-positive and Gram-negative bacteria, atypical pathogens, and anaerobic bacteria, as well as species resistant to aminoglycosides, tetracyclines, and macrolide antibiotics. Beta-lactamase producing strains of Haemophilus influenzae and Moraxella catarrhalis are susceptible to moxifloxacin [14–17]. Moxifloxacin is strongly targeted to alveolar tissue [18, 19] and demonstrates rapid initial killing and eradication rates for pneumococcal bacteria .
The initial clinical program for moxifloxacin in AECB included two studies of moxifloxacin (400 mg once daily, 5 days) versus clarithromycin (500 mg twice daily, 7–10 days) and two studies versus cefuroxime axetil (500 mg twice daily, 10 days) in a total of 2381 patients [20, 21]. Together, these studies demonstrated that moxifloxacin achieved a clinical response rate of 89% and a bacteriological response rate of 87% at 7–14 days post-treatment.
In another, prospective, multicenter, randomized, double-blind study of outpatients with AECB (MOSAIC), 5-day moxifloxacin was associated with significantly higher clinical cure rates and bacterial eradication rates than a 7-day standard regimen (i.e. amoxicillin 500 mg three times daily, or clarithromycin 500 mg twice daily, or cefuroxime axetil 250 mg twice daily) . In addition, the time until next exacerbation was significantly greater with moxifloxacin than the comparator during 9-month follow-up , which may be attributed to more effective bacterial eradication by moxifloxacin . Post-hoc analyses of the MOSAIC study identified a beneficial influence on clinical cure rates from moxifloxacin treatment and a poorer outcome associated with cardiopulmonary disease, forced expiratory volume in 1 second (FEV1) < 50% predicted, and ≥ 4 AECBs in the previous year .
The recent MAESTRAL study of 1492 outpatients aged ≥ 60 years with moderate-to-severe AECOPD (Anthonisen grade I) showed that moxifloxacin (400 mg/day for 5 days) is as effective as amoxicillin/clavulanic acid (875/125 mg for 7 days) in clinical success rate, with a significantly lower failure rate in patients with confirmed bacterial AECOPD . The benefits of moxifloxacin (400 mg/day for 5 days) also translated into a more favorable long-term quality of life when compared with amoxicillin/clavulanate (500/125 mg three times daily for 10 days) in the general practice setting .
Based on the existing controlled trial evidence, researchers have concluded that moxifloxacin is as effective or even more effective compared with other antimicrobials, with a more advantageous dosage regimen that may be associated with increased compliance [27, 28].
Observational studies provide valuable information, alongside controlled clinical studies, with relevance to contemporary practice. Published data on 9225 patients aged ≥ 35 years with AECB or AECOPD from eight European countries, from among the 46 893 patients recruited globally to an observational study of moxifloxacin (the GIANT study), demonstrated very good or good efficacy for moxifloxacin in 94.9% of patients and very good or good tolerability in 96.7%, based on physician assessments .
Few data exist on the outpatient antibiotic management of AECB/AECOPD in Eastern/South Eastern Europe, and in particular on the use of moxifloxacin in this population. The current non-interventional observational study was conducted to gain further information on the treatment of AECB with moxifloxacin in a large population of outpatients with moderate-to-severe AECB recruited from countries in South Eastern/Eastern Europe and Kazakhstan.