[Diagnosis and ambulatory treatment of patients with community-acquired pneumonia: variability of complementary tests and study of the effectiveness of roxithromycin. Study Group on Ambulatory Treatment of Community-Acquired Pneumonia (NACTA)].

BACKGROUND: Community-acquired pneumonia (CAP) has been the subject of a number of studies. Nevertheless, studies focused on effectiveness of therapy and variability of diagnostic tests are scarce.

PATIENTS AND METHODS: Observational study of the diagnostic methodology used in patients attending hospital Emergency Departments for possible CAP and assessment of effectiveness and reliability of empiric ambulatory therapy with roxithromycin (150 mg/12 h, for a minimum of ten days). The only mandated complementary tests included PA and lateral chest X-ray views and blood count. Microbiological tests were left to the discretion of the attending physician. Clinical and biological follow-up of the patient consisted of three outpatient visits.

RESULTS: The study was conducted at 18 spanish hospitals from October 1997 to March 1998. The final total of patients with CAP enrolled was 161 (75 women and 86 men). Three patients required hospital admission. In a 3% of patients the Gram staining of the sputum specimen was performed; in 53% of patients blood cultures were obtained (3.4% were positive) and in 23% of patients serological determinations are performed (16.7% were positive). The final microbiological results led to the disclosure of the etiologic agent of CAP in 5.5% of patients. In only one patient did the results prompt a change in antibiotic therapy. The clinical course was favorable in 92.5% of patients. In 12 patients (7.5%) a change of antibiotic was made or a second antibiotic was added. The mean therapy duration with roxithromycin was 11.9 days (range: 7-22 days). In five patients (3.1%), the observed adverse events were attributed to roxithromycin, and in no case was discontinuation of therapy necessary.

CONCLUSIONS: The variability of diagnostic tests used in patients with CAP is remarkable but their yield is of little effect. Patients with CAP candidates for ambulatory therapy can receive empiric antibiotic therapy with roxithromycin. In this series, roxithromycin had a high clinical effectiveness and was well tolerated.