Infecções do trato respiratório inferior são empiricamente tratadas com antibióticos mesmo sem evidências clínicas de etiologia bacteriana. Sabe-se que alguns precursores séricos da calcitonina, dentre eles a procalcitonina, se elevam em presença de atividade bacteriana. Artigo publicado no periódico The Lancet buscou avaliar se os níveis desta substância constituem bom critério para se determinar a etiologia e guiar o tratamento farmacológico das infecções do trato respiratório inferior. Após ensaio envolvendo 243 pacientes, os autores, afiliados de hospitais universitários da Suíça, observaram significativa redução do emprego desnecessário de antibioticoterapia em quadros infecciosos autolimitados.
Mirjam Christ-Crain, Daiana Jaccard-Stolz, Roland Bingisser, Mikael M Gencay, Peter R Huber, Michael Tamm, Beat Müller
Department of Internal Medicine (M Christ-Crain MD, R Bingisser MD, B Müller MD), Division of Pneumology (D Jaccard-Stolz MD, Prof M Tamm MD), Division of Endocrinology (M Christ-Crain, B Müller), Department of Research (M M Gencay PhD, Prof M Tamm, B Müller MD), and Department of Clinical Chemistry (Prof P R Huber PhD), University Hospitals, Petersgraben 4, CH-4031 Basel, Switzerland
Correspondence to: Dr Beat Müller (e-mail:happymiller@bluewin.ch)
Background Lower respiratory tract infections are often treated with antibiotics without evidence of clinically relevant bacterial disease. Serum calcitonin precursor concentrations, including procalcitonin, are raised in bacterial infections. We aimed to assess a procalcitonin-based therapeutic strategy to reduce antibiotic use in lower respiratory tract infections with a new rapid and sensitive assay.
Methods 243 patients admitted with suspected lower respiratory tract infections were randomly assigned standard care (standard group; n=119) or procalcitonin-guided treatment (procalcitonin group; n=124). On the basis of serum procalcitonin concentrations, use of antibiotics was more or less discouraged (<0·1 µg/L or <0·25 µg/L) or encouraged (
0·5 µg/L or
0·25 µg/L), respectively. Re-evaluation was possible after 6-24 h in both groups. Primary endpoint was use of antibiotics and analysis was by intention to treat.
Findings Final diagnoses were pneumonia (n=87; 36%), acute exacerbation of chronic obstructive pulmonary disease (60; 25%), acute bronchitis (59; 24%), asthma (13; 5%), and other respiratory affections (24; 10%). Serological evidence of viral infection was recorded in 141 of 175 tested patients (81%). Bacterial cultures were positive from sputum in 51 (21%) and from blood in 16 (7%). In the procalcitonin group, the adjusted relative risk of antibiotic exposure was 0·49 (95% CI 0·44-0·55; p<0·0001) compared with the standard group. Antibiotic use was significantly reduced in all diagnostic subgroups. Clinical and laboratory outcome was similar in both groups and favourable in 235 (97%).
Interpretation Procalcitonin guidance substantially reduced antibiotic use in lower respiratory tract infections. Withholding antimicrobial treatment did not compromise outcome. In view of the current overuse of antimicrobial therapy in often self-limiting acute respiratory tract infections, treatment based on procalcitonin measurement could have important clinical and financial implications.
Lancet 2004;
363: 600-07.
