Arnold 2016.

Methods	Allocation: randomised Blinding: double‐blind Controlled: placebo Centre: multi Arm: 2 arms, parallel groups Imputation: BOCF Study dates: 55‐month trial (May 2010 to December 2014)
Participants	Inclusion criteria: adolescents with fibromyalgia, Yunus and Masi diagnostic criteria, mean daily pain rating NRS score of ≥ 4 (0 to 10). Exclusion criteria: pain due to other conditions, systemic inflammatory MSK disorders, rheumatic diseases other than fibromyalgia, serious active infections, untreated endocrine disorders, prior participation in a clinical trial of pregabalin, history of failed treatment with pregabalin, mental health conditions, active malignancy, immunocompromised, or history of drug abuse. Baseline characteristics N = 107 Age: 12 to 17 years Gender: male (15); female (92) Number randomised: intervention (54); placebo (53) Number completed: intervention (44); placebo (36) Setting and location: 36 centres in the USA (28), India (5), Taiwan (2), and Czech Republic (1)
Interventions	Intervention group (N = 54): flexible‐dose pregabalin 75 to 450 mg/day Control group (N = 53): flexible‐dose placebo 75 to 450 mg/day Study duration: 15 weeks' duration including 4 phases: doses were optimised over 3 weeks based on efficacy and tolerability to 75, 150, 300, 450 mg/day. Remaining at that dose for 12 weeks.
Outcomes	Primary outcomes Mean pain score (NRS 0 to 10) Secondary outcomes Change in pain score by week Change in pain score at week 15 PGIC (Patient Global Impression of Change)
Notes	Sources of funding: sponsored by Pfizer. Medical writing support was provided. Trial registrations: NCT01020474; NCT01020526.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Subjects were randomized 1:1 to receive pregabalin or matched placebo according to a computer‐generated pseudo‐random code using the method of random permuted blocks."
Allocation concealment (selection bias)	Unclear risk	Comment: no information provided.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "this was a double‐blind study", "pregabalin or matched placebo was administered twice daily"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "Under this approach, a blinded assessment of the change in mean pain score of the 95 subjects who had been randomized at that point was conducted"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: all participants were accounted for.
Selective reporting (reporting bias)	Low risk	Comment: all planned outcomes listed in the methods were reported in the results.
Size	High risk	Comment: total participants > 50 per treatment arm randomised. Participants < 50 per treatment arm completed.
Other bias	Unclear risk	Comment: see notes above for details on Pfizer funding.