Nachemson 1995.

Methods	Multicentre multinational prospective cohort trial. 8 centres enrolled; included only physicians who firmly believed in effectiveness of bracing or who firmly believed that bracing was ineffective. Each physician consecutively enrolled all participants who met the inclusion criteria and prescribed only 1 treatment
Participants	240 girls with AIS; mean age 12.7 years; Cobb angle 30‐35°: 42% in the observation group and 65% in the brace group; Cobb angle 20‐29°: 58% in the observation group and 35% in the brace group; menarche at baseline: 57% in the observation group and 41% in the brace group; imbalance: 46% in the observational group and 25% in the brace group
Interventions	Experimental: plastic brace worn for at least 16 hours per day (111 girls) Control: observation only (who received the electrical stimulation referred to in the text) (129 girls)
Outcomes	Failure of treatment as measured by an increase of the curve of ≥ 6°, noted on 2 consecutive roentgenograms performed every 4 months before menarche and every 6 months after menarche
Notes	Length of follow‐up: 16 years after maturity
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Prospective cohort study
Allocation concealment (selection bias)	High risk	Prospective cohort study
Blinding of participants and personnel (performance bias) subjective outcomes	High risk	Blinding of participants not possible for the type of interventions compared (brace vs. no treatment)
Blinding of participants and personnel (performance bias) objective outcomes	Low risk	Blinding of participants not possible for the type of interventions compared (brace vs. no treatment) but outcomes unlikely to be influenced by lack of blinding
Blinding of outcome assessment (detection bias) subjective outcomes	Unclear risk	No subjective outcomes measured
Blinding of outcome assessment (detection bias) objective outcomes	Low risk	Roentgenograms read by providers, but objective outcomes unlikely to be influenced by lack of blinding
Incomplete outcome data (attrition bias) were drop‐out reported and equal between groups?	High risk	7% lost at follow‐up in the control group; 21% lost at follow‐up in the experimental group Comment: percentage unbalanced between groups, but worst‐case analysis performed
Incomplete outcome data (attrition bias) were all randomized participants analyzed in the group to which they were allocated?	High risk	Quote: "the patients lost at follow‐up were included in the survivorship analysis for the time they were in the study" Quote: "the 23 patients who dropped out from the brace group were analysed in the worst‐case analysis and considered as treatment failure" Comment: only the participants who dropped out from the experimental group were included in the worst‐case analysis
Selective reporting (reporting bias)	Low risk	Results from all pre‐specified outcomes have been adequately reported
Groups similar at baseline	High risk	Comparability of cohorts on the basis of the design or analysis: more participants with severe scoliosis (30‐35° in the brace group (65% with brace vs. 42% with observation); fewer participants with imbalance in the brace group (25% with brace vs. 46% with observation); menarche at baseline: 41% with brace vs. 57% with observation No adjustment for most important confounding factors Comment: differences at the baseline were in favour of the control group
Co‐interventions	Unclear risk	Not reported
Compliance with intervention	Unclear risk	Not reported
Similar outcome timing	Low risk	All participants received a roentgenogram every 4 months before menarche and every 6 months after menarche
Representativeness of the exposed cohort	Low risk	Truly representative of the average adolescents with scoliosis
Selection of the non‐exposed cohort	High risk	Drawn from a different source
Ascertainment of exposure	Low risk	Secure record (e.g. clinical records)