Chen 2010.

Methods	Randomised, placebo‐controlled, double‐blind trial
Participants	57 participants aged ≥ 5 years who fulfilled international classification criteria for SMA types II or III and with a homozygous deletion of the SMN1 gene Inclusion criteria: having type 2 or 3 SMA, aged ≥ 5 years; and with a confirmed genetic diagnosis owing to a homozygously deleted SMN1 gene Disease severity was categorised according to the International Classification for SMA, which is based on age at disease onset and maximum function. Exclusion criteria: evidence of impaired renal, hepatic or haematopoietic function history of severe antenatal asphyxia congenital anomalies other than SMA intermittent (≥ 16 hours per day) or continuous requirement for mechanical ventilation prior major surgery or any procedure needing generalised anaesthesia during the past 6 months participation in any other clinical trial or administration of any agents that potentially benefit SMA within the past 6 months
Interventions	Oral hydroxyurea in escalating dose from 10 mg/kg to 20 mg/kg over 8 weeks (5 mg/kg increase per 4 weeks) or placebo in increasing dose over 8 weeks Duration of treatment: 18 months Follow‐up: 6 months post‐treatment
Outcomes	Change in functional score (GMFM), change in functional score in non‐ambulatory patients (HFMS), change in muscle strength (MMT), change in pulmonary function (FVC), adverse events
Funding	Quote: "Supported by Department of Health, Executive Yuan, Taiwan (DOH96‐TD‐I‐111‐TM013) and in part by Sun's KMU‐SMA fund."
Conflicts of interest	Most authors reported research support from Department of Health, Executive Yuan, Taiwan and Sun's KMU‐SMA fund. 2 authors reported patents regarding hydroxyurea treatment for SMA and method for diagnosis of SMA.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomly assigned. No methods of randomisation described.
Allocation concealment (selection bias)	Unclear risk	No details of randomisation given.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Participants, families, investigators, study co‐ordinators, evaluators and statisticians were blinded. Randomisation unit and study pharmacist were not blinded.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Participants, families, investigators, study co‐ordinators, evaluators and statisticians were blinded. Randomisation unit and study pharmacist were not blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data.
Selective reporting (reporting bias)	High risk	Data on muscle strength dichotomised post hoc.
Other bias	Low risk	None identified.