Skljarevski 2010b.

Study characteristics
Methods	Design: parallel Duration: 12 weeks Assessment: baseline and post‐intervention Country: Germany, Netherlands, Poland, Russia, Spain and USA
Participants	Pain condition: low back pain Population: adults with chronic low back pain Minimum pain intensity: ≥ 4 on 0‐10 scale Inclusion criteria Outpatients with chronic low back pain as their primary painful condition present on most days for at least 6 months and a rating of ≥ 4 on BPI pain intensity item Exclusion criteria Low back surgery in previous year Major depressive disorder and other psychiatric disorders excluded Total participants randomised: 401 Age in years (mean): 54.1 Gender: 246/401 were female Pain duration in years (mean): 8.3
Interventions	Placebo n = 203 Inert Duloxetine 60 mg n = 198 SNRI Fixed dose
Outcomes	Pain intensity Sleep Mood Physical function Quality of life Moderate pain relief Substantial pain relief PGIC AEs SAEs Withdrawal
Missing data methods	ITT with LOCF, BOCF for sensitivity analyses of primary outcome
Funding source	Pharmaceutical: Eli Lilly and Company
Conflicts of interest	Drs Skljarevski and Desaiah, Ms Zhang, and Ms Alaka are employees of Eli Lilly and Company and hold company stocks. Drs Palacios, Miazgowski, and Patrick were study investigators and received funding from Eli Lilly and Company, Indianapolis, Indiana. These external authors had access to the data relevant to this manuscript.
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
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	States double‐blind but no information on study drug appearance or matched dosing
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Self‐reprorted outcomes from participants, but uncertain of blinding procedures
Incomplete outcome data (attrition bias) All outcomes	Low risk	Used ITT with LOCF but for primary outcome used BOCF and mBOCF for sensitivity analysis. Results using all methods of imputation were significant. Attrition Total: 98/401 (24.4%) Placebo: 47/203 (23.2%) Duloxetine 60 mg: 51/198 (25.8%)
Selective reporting (reporting bias)	Low risk	Published outcomes match protocol
Other bias	Unclear risk	In the trial registry they've registered 2 research sites in Brazil but have just not mentioned it anywhere after, no reason for excluding those centres stated