Many Factors are Responsible for Treatment Outcome in Acute Exacerbations of Chronic Bronchitis

Abstract & Commentary

By Joseph Varon, MD, FACP, FCCP, FCCM, Professor, University of Texas Health Science Center, Houston; St. Luke's Episcopal Hospital, Houston. Dr. Varon reports no financial relationship to this field of study.

Synopsis: The number of previous acute exacerbations of chronic bronchitis (AECBs) and the baseline FEV1 level are potent prognostic factors of the short- and long-term outcomes of AECB.

Source: Wilson R, et al. Antibiotic treatment and factors influencing short and long term outcomes of acute exacerbations of chronic bronchitis. Thorax. 2006;61:337-342.

This multicenter study was aimed at evaluating the short- and long-term outcome of patients with AECB treated with antibiotics. The study was designed as a prospective, randomized, double-blinded trial and was part of the MOSAIC study. Outpatients aged ≥ 45 years with documented chronic bronchitis were eligible for inclusion during an AECB-free period if they had a smoking history of at least 20 packs years, 2 or more documented AECBs in the previous year, and a forced vital capacity in one second (FEV1) of < 85% of predicted at the enrollment visit. Patients were then randomized to received either moxifloxacin (400 mg daily for 5 days) or one of the following comparators: amoxicillin (500 mg three times daily for 7 days), clarithromycin (500 mg twice daily for 7 days), or cefuroxime-axetil (250 mg twice daily for 7 days). Clinical response was evaluated 7-10 days at the end of the treatment. Factors with potential impact on the clinical outcomes studied included: age (> 65 or < 65 years), body mass index (< 30 kg/m2 or > 30 kg/m2), gender, co-morbidities, number of AECBs in the previous years (severity of chronic bronchitis), concomitant medications and FEV1.

Seven hundred-thirty patients were studied. The mean age was 63.2 ± 9.8 years; 43.2% had an FEV1 < 50% and 27.7% had ≥ 4 exacerbations the previous year. Moxifloxacin was independently associated with a higher cure rate than the comparator drugs while co-morbidities, FEV1, 50% predicted, and ≥ 4 AECBs in the previous year had a detrimental effect on the outcome.

Once adjustments were made, in univariate analysis, the factors that had a significant impact on the occurrence of the composite event were ≥ 4 AECBs in the previous year, age > 65 years, FEV1 < 50% predicted and acute bronchodilator use had a statistically significant effect on long-term outcome. The effect noted for moxifloxacin was primarily linked to benefits in the subgroup of patients aged > 65 years.

Commentary

AECBs are commonly seen in primary care practices worldwide. This study is interesting because it reaffirms that the severity of airflow obstruction, coexistent comorbidities (such as cardiac disease) and the frequency of exacerbations are risk factors for poorer short-term outcomes in AECB.

A number of studies in the past decade have shown similar results in patients with AECB.1-3 Ball and co-workers have demonstrated that a past history of frequent exacerbations makes a future exacerbation more likely.4 This is perhaps because the index exacerbation is not completely resolved and these patients tend to have persistent bacterial infection. Aggressive antibiotic treatment is therefore justified in patients meeting criteria. It is interesting to note that among the agents studied, moxifloxacin had a beneficial effect in the short- and long-term outcome, despite presence of other negative prognostic factors.

References

1. Dewan NA, et al. Acute exacerbation of COPD: factors associated with poor treatment outcome. Chest. 2000;117:662-671.

2. Miravitlles M, et al. Factors associated with increased risk of exacerbation and hospital admission in a cohort of ambulatory COPD patients: a multiple logistic regression analysis. The EOLO Study Group. Respiration. 2000;67:495-501.

3. Grossman R, et al. A 1-year community-based health economic study of ciprofloxacin vs usual antibiotic treatment in acute exacerbations of chronic bronchitis: the Canadian Ciprofloxacin Health Economic Study Group. Chest. 1998;113:131-141.

4. Ball P, et al. Acute infective exacerbations of chronic bronchitis. QJM. 1995;88:61-68.