Worrall 2007a.

Study characteristics
Methods	Clinical setting: family doctors’ offices Single‐ or multicentre study: multicentre Country of study: Canada Unit of allocation: clusters Inclusion criteria: patients aged 19 years or older who presented with acute sore throat as their primary symptom Exclusion criteria: not reported Follow‐up: not reported
Participants	Number of clusters (n): 37 Number of participants (n): 533 Participant characteristics: age (distribution): not reported; female participants (%): not reported; clinical severity distribution of Centor/McIsaac score: not reported.
Interventions	Management in intervention group(s): RADT alone (“RADT arm”); RADT in combination with clinical examination/scoring system (“STDR and RADT arm“: score of ≤ 1, no need for antibiotics; 3 or 4, antibiotics are required; doctors were asked to use the rapid test only when the score was 2). Type of RADT system used: enzyme immunoassay Commercial name and brand of the RADT: Clearview Exact Strep A dipstick (Wampole Laboratories) Management in control group(s): clinical grounds without a scoring system (“Control arm”); clinical grounds with a scoring system (“STDR arm”: score of ≤ 1, no need for antibiotics; 3 or 4, antibiotics are required; 2, antibiotics might or might not be beneficial).
Outcomes	Primary outcome(s): rate of antibiotic prescribing Secondary outcome(s): types of antibiotics prescribed
Notes	Type of report: journal article Source(s) of funding: not reported RCT registration number: not reported The trial had 4 arms: 1. Usual practice (“Control arm”), 2. Decision rule only (“STDR arm”), 3. Rapid antigen test only (“RADT arm”), 4. Decision rule and antigen test combined (“STDR and RADT arm“). The clinical scoring system used was a slightly modified Centor score. There is no report of participant characteristics. The authors explain that they ”did not ask doctors to record clinical or demographic characteristics of the patients” because they “wanted the doctors to do as little extra work as possible”.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"The 40 physicians who agreed to take part in the study were randomly allocated to 1 of 4 trial arms [...]." No description exists on the generation of the allocation sequence.
Allocation concealment (selection bias)	Unclear risk	No description exists of any concealment of allocation.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding is impossible in this context, and this lack of blinding is likely to influence the outcome.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Blinding is impossible in this context, and this lack of blinding is likely to influence the outcome.
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants entered into the study appear to have been assessed for antibiotic prescription. There is no mentioning of handling, or existence, of incomplete outcome data (exclusion, attrition, etc.), but the risk of bias is considered low.
Selective reporting (reporting bias)	Low risk	Unclear description of what outcomes are included in study; despite this, relevant outcomes are reported in the Results. There is no protocol to be used for comparison regarding outcomes mentioned.
Other bias	Low risk	None

GABHS: group A beta‐haemolytic streptococcus
RADT: rapid antigen detection test
RCT: randomised controlled trial
SD: standard deviation
STDR: sore throat decision rule