We have read with interest the suggestions for treatment of respiratory tract infections in JFP.1 We congratulate the authors on the clarity of the message conveyed. Indications for antibiotics can vary according to each country due to differing degrees of resistance of the most frequently isolated respiratory germs. But we agree with the authors that the most important itemis whether the patient requires an antibiotic.
The literature has shown that antibiotics are slightly more effective than place-bo in the treatment of exacerbations of moderate-severe chronic obstructive pulmonary disease (COPD) and should be recommended when at least 2 of the Anthonisen criteria are presented.2 Among all the placebo-controlled studies performed, that published by Anthonisen et al in 1987 continues to be the reference study.3 They reported that 55% of the exacerbations of COPD in the placebo group resolved spontaneously. This study included moderate-severe patients.
One of the problems that general practitioners have is to know whether a determined exacerbation is due to a bacterial agent or not, and thus, whether antimicrobial treatment is necessary. Few clinical studies have evaluated the role of antibiotic therapy in mild COPD and none of the studies undertaken have demonstrated that antibiotics are indeed beneficial in exacerbations of this disease. It may be stated that the microbiologic studies which have analyzed the frequency of isolating suspicious pathogens only find 50% of the exacerbations, even in patients requiring hospitalization, and the more severe the patient the greater the frequency of isolation, being arguable in patients with mild COPD.4 In these cases the effectiveness of sputum cultures is poor and in many cases potentially pathogenic microorganisms are not isolated, in contrast with the finding of pathogenic microorganisms in patients with advanced disease.5
The benefits of antibacterial treatment has only been demonstrated in patients with moderate-severe COPD in whom potentially pathogenic microorganisms are isolated. We think that the indications for the antibiotics in chronic bronchitis can lead to misunderstandings; probably it would be more useful to classify these patients according to the severity of their condition. COPD in those who have a forced expiratory volume in 1 second of 60% of predicted or more behave similarly to those with acute bronchitis with a mainly viral cause, cases in which the use of antibiotics is not recommended.6 Taking the microbiological basis of uncomplicated acute bronchitis into account, it is not surprising that in the few studies that evaluated the role of antibiotics in exacerbations of mild COPD, no benefits have been observed. While there are no other studies in this subgroup of patients with limitations in air flow, antibiotics should not, initially, be prescribed and bronchodilator medication, hydration and natural measures should be used as in cases of acute bronchitis. For this reason we should recommend the use of spirometry to be able to treat these patients adequately.
Carl Llor, PhD, and Ana Moragas, MD
Primary Healthcare Center Jaume I, Tarragona, Spain