Summary of data items to be extracted from the included studies
| Study and participants characteristics | Reference, year, country, design of study, age, gender, sample size (used in the analysis), type of intervention (including but not limited to casting, traditional growing rods, magnetic growing rods, VEPTR (Vertical Expansile Prosthetic Titanium Rib), Shilla, Tether), diagnostic subgroups of participants (congenital/idiopathic/syndromic/neuromuscular), curve severity and curve pattern |
| Outcome measure | Name of outcome measure, version of outcome measure, means of scores, mode of administration, recall period, subscale, numbers of items, response option, response rate, missing items, setting, target population, scoring, original language, available translation |
| Measurement properties | Validity : Type of validity, descriptive statistics, missing value, comparator outcome or predictor outcome, hypothesis, statistics methods (including IRT/CTT), CI, validation results, sample size |
| Reliability : Type of reliability, descriptive statistic, time interval, reliability coefficient, measurement error, sample size, number of repeated measurements | |
| Responsiveness: Method of testing : hypothesis testing versus distribution based (ES, SRM and MDC) vs anchor-based (MIC or MCIC or MID), time to follow-up, curve severity at baseline and follow-up, curve aetiology, treatment modality | |
| Interpretability : Distribution of score in the study population, percentage of missing items, floor and ceiling effects, scores and change scores available for relevant (sub)groups, information on response shift | |
| Feasibility : Patient’s comprehensibility, clinician’s comprehensibility, type and ease of administration, length of instrument, completion time, patient’s required mental and physical ability level, ease of standardisation, ease of score calculation, cost of instrument, required equipment, availability in different settings, regulatory agency’s requirement for approval |
CTT, classical test theory; ES, effects size; IRT, item-response theory; MCIC, minimal clinically important change; MDC, minimal detectable change; MIC, minimal important change; MID, minimal important difference; SRM, standardised response mean.