title: Procalcitonin-guided antibiotic use versus a standard approach for acute respiratory tract infections in primary care: study protocol for a randomised controlled trial and baseline characteristics of participating general practitioners [ISRCTN73182671].
abstract: BACKGROUND
  Acute respiratory tract infections (ARTI) are among the most frequent reasons for consultations in primary care. Although predominantly viral in origin, ARTI often lead to the prescription of antibiotics for ambulatory patients, mainly because it is difficult to distinguish between viral and bacterial infections. Unnecessary antibiotic use, however, is associated with increased drug expenditure, side effects and antibiotic resistance. A novel approach is to guide antibiotic therapy by procalcitonin (ProCT), since serum levels of ProCT are elevated in bacterial infections but remain lower in viral infections and inflammatory diseases. The aim of this trial is to compare a ProCT-guided antibiotic therapy with a standard approach based on evidence-based guidelines for patients with ARTI in primary care.
  
  
  METHODS
  This is a randomised controlled trial in primary care with an open intervention. Adult patients judged by their general practitioner (GP) to need antibiotics for ARTI are randomised in equal numbers either to standard antibiotic therapy or to ProCT-guided antibiotic therapy. Patients are followed-up after 1 week by their GP and after 2 and 4 weeks by phone interviews carried out by medical students blinded to the goal of the trial. Exclusion criteria for patients are antibiotic use in the previous 28 days, psychiatric disorders or inability to give written informed consent, not being fluent in German, severe immunosuppression, intravenous drug use, cystic fibrosis, active tuberculosis, or need for immediate hospitalisation. The primary endpoint is days with restrictions from ARTI within 14 days after randomisation. Secondary outcomes are antibiotic use in terms of antibiotic prescription rate and duration of antibiotic treatment in days, days off work and days with side-effects from medication within 14 days, and relapse rate from the infection within 28 days after randomisation.
  
  
  CONCLUSIONS
  We aim to include 600 patients from 50 general practices in the Northwest of Switzerland. Data from the registry of the Swiss Medical Association suggests that our recruited GPs are representative of all eligible GPs with respect to age, proportion of female physicians, specialisation, years of postgraduate training and years in private practice.
authors.affiliation: Basel Institute for Clinical Epidemiology, University Hospital Basel, CH-4031 Basel, Switzerland. brielm@uhbs.ch
authors.forename: Matthias
authors.initials: M
authors.lastname: Briel
authors.forename: Mirjam
authors.initials: M
authors.lastname: Christ-Crain
authors.forename: Jim
authors.initials: J
authors.lastname: Young
authors.forename: Philipp
authors.initials: P
authors.lastname: Schuetz
authors.forename: Peter
authors.initials: P
authors.lastname: Huber
authors.forename: Pierre
authors.initials: P
authors.lastname: Périat
authors.forename: Heiner C
authors.initials: HC
authors.lastname: Bucher
authors.forename: Beat
authors.initials: B
authors.lastname: Müller
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D000906:Antibodies / Q000097:blood; D001424:Bacterial Infections / Q000175:diagnosis* / Q000188:drug therapy; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D002985:Clinical Protocols; D016903:Drug Monitoring; D017723:Drug Utilization Review / Q000706:statistics & numerical data*; D019317:Evidence-Based Medicine; D005194:Family Practice / Q000592:standards*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care / Q000592:standards*; D011498:Protein Precursors / Q000097:blood*; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D012107:Research Design; D012141:Respiratory Tract Infections / Q000175:diagnosis* / Q000188:drug therapy*; D013557:Switzerland; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D000906:Antibodies; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide