Mas‐Dalmau 2021.

Study characteristics
Methods	Randomised controlled trial
Participants	436 children aged 2 to 14 years with uncomplicated respiratory infections (pharyngitis, rhinosinusitis, acute bronchitis, acute otitis media) who attended, with their parent(s), 39 primary care paediatrician's offices in Spain 146 children were randomised to delayed antibiotics, 148 to immediate antibiotics and 142 to no antibiotics Age: the mean age of participants in the delayed antibiotic group was 6.4 years (SD 3.2), in the immediate antibiotic group was 6.4 years (SD 3.1) and in the no antibiotic group was 6.1 years (SD 6.1) Sex:delayed antibiotic group: 78 males, 68 females; immediate antibiotic group: 69 males, 79 females; no antibiotic group: 63 males, 79 females Exclusion criteria: acute otitis media: otoscopy with isolated tympanum erythema plus isolated crying, history of fever (low likelihood of otitis diagnosis); history suggestive of serous otitis or chronic suppurative otitis media; serious chronic disease, such as cystic fibrosis or valve heart disease; high fever with crying and severe earache; bilateral involvement; purulent otorrhoea (ear discharge); previous complications (septic complications, hearing disturbances); antibiotic intake in the previous 2 weeks; symptoms lasting ≥ 4 days; and poor general health status (high fever, hypotonic, somnolence, no response to antipyretic). Rhinosinusitis: clinical presentation for < 1 week, antibiotic intake in the previous 2 weeks and using C‐reactive protein quick tests during the visits Pharyngitis: other causes of sore throat such as ulcers, aphthous ulcer or thrush; no presence or presence of 1 or 4 Centor criteria, antibiotic intake in the previous 2 weeks, a history of rheumatic fever, a history of peritonsillar abscess, recurrent pharyngotonsillitis (> 5 episodes in the previous year), and using quick antigenic techniques during the visit. Acute bronchitis: children < 3 years old; suspected pneumonia (crepitant, tubular breath sound, unilateral asymmetric hypophonesis, tachypnoea, vomiting, severe diarrhoea); high fever (axillary temperature > 38.5 °C); vomiting and/or severe diarrhoea; bronchial asthma; other acute or chronic lung diseases including cystic fibrosis; active heart disease; psychiatric diagnoses; antibiotic intake in the previous 2 weeks; and using C‐reactive protein quick tests during the visit.
Interventions	Delayed antibiotic prescription, immediate antibiotic prescription, no antibiotic prescription
Outcomes	Primary outcome: severity and duration of acute respiratory tract infection (pharyngitis, rhinosinusitis, acute bronchitis or acute otitis media) symptoms over 30 days Secondary outcomes: antibiotic use over 30 days, parental satisfaction and beliefs regarding antibiotic efficacy, and additional unscheduled visits to primary care over 30 days
Notes	The study was funded by the Instituto de Salud Carlos III
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation was stratified by pathology and in blocks. The nature of the blocks was not described.
Allocation concealment (selection bias)	High risk	Children, parents and health professionals were not blinded
Blinding (performance bias and detection bias) All outcomes	High risk	Children, parents and health professionals were not blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	436 participants were recruited and included in the analysis. Intention‐to‐treat guided all analyses.
Selective reporting (reporting bias)	Low risk	No evidence of selective reporting
Other bias	Low risk	Funded by government body