Aetiology and therapy of community-acquired pneumonia: a hospital study in northern Italy

Objectives: The primary aim of this study was to determine whether the use of a therapeutic protocol in the treatment of community-acquired pneumonia (CAP) proved equally effective as the initial empirical anti-infective therapy usually employed. A secondary aim was to compare the cost of therapy and the incidence of the pathogens responsible for so-called “atypical” pneumonia in the study area. Methods: A comparison was made between 11 hospital departments agreeing to abide by the study protocol and 12 hospital departments, well matched for size and type, implementing their usual therapy. The protocol provided different anti-infective therapy options for the patients regarded as being at risk and not at risk, and, secondarily, for infections likely to be of the “typical bacterial” or so-called “atypical” type. The main outcome measures were need to change the initial anti-infective therapy owing to inefficacy, final clinical and radiological outcome, mean cost of pharmacological therapy per patient and result of the serological investigations of the pathogens responsible for “atypical” pneumonia. Results: A total of 345 patients with CAP were assessed. The initial therapy was changed in 8.6% of patients treated according to the protocol, and in 24.5% of patients treated with the usual anti-infective therapies. The cost of therapy for the protocol was almost half of that in the control group. Clinical and radiological outcome was similar in the two groups, with a very low mortality rate. The overall proportion of cases of “atypical” pneumonia amounted to 13%. Conclusions: The use of the therapeutic protocol gave an efficacy comparable to that achieved with routine therapy, but at a distinctly lower cost of antibiotic therapy. The use of microbiological investigations is very limited in day-to-day clinical practice, and the incidence of so-called “atypical” pneumonia was low in the study area, apart from specific outbreaks. Received: 28 May 1996 / Accepted in revised form: 21 August 1996