Newswise — Antibiotic therapy leads to fewer treatment failures and deaths among people suffering from moderate to severe flare-ups in lung diseases such as emphysema and chronic bronchitis, according to a new systematic review.
The analysis compared outcomes among patients who received either antibiotics or a placebo when they experienced acute flare-ups of chronic obstructive pulmonary disease.
"Our study is the first to show clinically measurable beneficial effects of antibiotic therapy in exacerbations of COPD," said lead author Dr. Felix Ram of New Zealand's Massey University. "This has been one of the most highly debated topics in respiratory medicine for years."
However, the various trials focused on a wide range of patients, including those undergoing treatment in doctors' offices, hospital wards and intensive care units.
"These results should be interpreted with caution due to the differences in patient selection, antibiotic choice, small number of included trials and lack of control for [other] interventions that influence outcome," say the authors.
COPD includes a group of disorders that result in chronic blockage of air flow. Cardinal symptoms include shortness of breath, coughing and sputum production. For many patients these symptoms worsen noticeably from time to time, and antibiotics are commonly given to provide relief.
Controversy over this practice arises from data suggesting that at least one-third of these acute episodes are not caused by bacteria. Unnecessary use of antibiotics may promote emergence of drug-resistant organisms.
The review appears in the most recent issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
Two of the study's five co-authors have lectured for, had consultancy arrangements with or received research funding from pharmaceutical companies that manufacture antibiotics.
Eleven randomized controlled trials totaling 917 patients with moderate to severe COPD were included in the review. Use of antibiotics reduced the risk of treatment failure by 53 percent.
Short-term mortality data were reported for 356 patients. Six of the 180 patients who received antibiotics died during study interventions, compared with 27 of the 176 patients in the placebo group.
These figures suggest that for every eight patients receiving antibiotics one death could be prevented, according to Ram. For every three patients treated, one would avoid the need for additional medical treatment, making it a cost-effective therapy.
"There is no reason to withhold treatment with antibiotics in exacerbations of COPD for fear of lack of clinical efficacy and contribution to the increase in bacterial resistance," he said in an e-mail.
As might be expected the benefits are greatest in severely ill patients who are hospitalized, the review says. The two studies that looked only at outpatients showed no difference between antibiotic therapy and placebo.
A considerable challenge in conducting this meta-analysis was that nearly half of the included trials took place more than 20 years ago. The definition of COPD and its symptoms has evolved considerably since then.
The authors note that meta-analysis incorporating only the six most recent studies produced essentially the same results as the overall review. Nevertheless they acknowledge, "Differences in disease definition may bias our results and this cannot be avoided as it reflects the history of research in COPD."
"This review does suggest that there is a beneficial effect for antimicrobial therapy," said Fernando Martinez, M.D., a pulmonologist at the University of Michigan. "You do have to be very careful in interpreting these studies to apply to individual patients. What we now have to do is better define in whom, when and which antibiotics."
Much of this research is currently under way. The review recommends further studies on how severity of disease influences treatment results, and Ram's team is comparing the relative benefits of specific antibiotics.
The reviewers do close the book on one aspect of COPD research. "We do not believe that it would be appropriate or ethical to conduct further studies using placebo in patients admitted to hospital," they say.
Martinez also said that prevention of acute episodes through prophylactic use of antibiotics and other medications is also an area of active investigation. "Exacerbations are major problems for people with COPD, clearly associated with worsening in their quality of life over time. Preventing these episodes is going to be the new era in COPD."
Ram FSF, et al. Antibiotics for exacerbations of chronic obstructive pulmonary diseases. The Cochrane Database of Systematic Reviews 2006, Issue 2.
The Cochrane Collaboration is an international nonprofit, independent organization that produces and disseminates systematic reviews of health care interventions and promotes the search for evidence in the form of clinical trials and other studies of interventions. Visit http://www.cochrane.org for more information.
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