Skljarevski 2010a.

Study characteristics
Methods	Design: parallel Duration: 13 weeks Assessment: baseline and post‐intervention Country: Brazil, France, Germany, Mexico, and Netherlands
Participants	Pain condition: low back pain Population: adults with chronic low back pain Minimum pain intensity: ≥ 4 on 0‐10 scale Inclusion criteria Chronic low back pain as the primary painful condition; pain must have been present in lower back (T‐6 or below) for most days for the past 6 months or longer with a weekly mean of 24‐hour average pain score of ≥ 4 out of 10 at baseline Exclusion criteria Any other pain condition, current depression, psychiatric conditions Total participants randomised: 236 Age in years (mean): 51.5 Gender: 144/236 were female Pain duration in years (mean): 9.2
Interventions	Placebo n = 121 Inert Sham matched dosing using same criteria as duloxetine arm Duloxetine 60‐120 mg n = 115 SNRI Participants who did not meet reponse criteria (30% pain relief) had their doses uptitrated blindly.
Outcomes	Pain intensity Mood Physical function Quality of life Sleep PGIC Moderate pain relief Substantial pain relief AEs SAEs Withdrawal
Missing data methods	ITT with LOCF
Funding source	Pharmaceutical: Eli Lilly and Company
Conflicts of interest	Drs Skljarevski, Desaiah, Liu‐Seifert, Zhang, Chappell, and Iyengar are employees and stockholders of Eli Lilly and Company. Dr Detke was a full‐time employee and a major stock holder of Eli Lilly andCompany until March 2009 and is currently a full‐time employee and a major stock holder of Medavante Corporation. Dr Atkinson serves on Lilly Pain Advisory Board. Dr Backonja serves on Lilly Pain Advisory Board and in addition performed clinical trials and received research funding from Allergan, Astellas, Johnson and Johnson, Lilly,Merck, NeurogesX, and Pfizer Corporate/Industry and Foundation funds were received in support of this work. One or more of the author(s) has/have received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this manuscript: e.g., honoraria, gifts, consultancies, royalties, stocks, stock options, decision‐making position.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation methods not specified
Allocation concealment (selection bias)	Unclear risk	Allocation procedures not specified; only mention voice centralised system for allocating participants to higher dose, not when randomising and allocating all sample
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	States double blind, matched dosing but no information on study drug appearance
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Self‐reported outcomes from participants, but uncertain of blinding procedures
Incomplete outcome data (attrition bias) All outcomes	High risk	ITT with LOCF. Some data are not the same in the protocol and the paper: more AEs reported on clinicaltrials.gov than in the paper. Participants did have significant differences as to why they have missing data: duloxetine group had significantly more withdrawals due to AEs. Attrition Total: 54/236 (22.9%) Placebo: 23/121 (19.0%) Duloxetine 60‐120 mg: 31/115 (27.0%)
Selective reporting (reporting bias)	Low risk	All outcomes match those registered on clinicaltrials.gov
Other bias	Low risk	No other sources of bias identified