Razazian 2014.

Study characteristics
Methods	Design: parallel Duration: 4 weeks Assessment: baseline, 2 days, 7 days, 14 days, 1 week post‐intervention Country: Iran
Participants	Pain condition: diabetic polyneuropathy Population: adults with diabetic polyneuropathy referred to diabetic clinic Minimum pain intensity: ≥ 40 on 0‐100 scale Inclusion criteria Diagnosis of metabolically stable type 1 or 2 diabetes with diabetic polyneuropathy according to the Boulton 2005 criteria History of neuropathic pain for at least 3 months Pain intensity of ≥ 40 on 0‐100 scale Exclusion criteria Any other pain condition, severe medical conditions including severe depression and psychotic disorders Total participants randomised: 257 Age in years (mean, SD): 56.3 (10.4) Gender: 156/257 were female Pain duration in months (mean, SD): 23.5 (2.5)
Interventions	Carbamazepine 400 mg n = 85 Anticonvulsant Fixed dose Pregabalin 150 mg n = 86 Anticonvulsant Fixed dose Venlafaxine 150 mg n = 86 SNRI Fixed dose
Outcomes	Moderate pain relief Substantial pain relief Sleep Mood AEs SAEs Withdrawal
Missing data methods	NR
Funding source	Non‐pharmaceutical: Kermanshah Univesity Of Medical Science
Conflicts of interest	NR
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were randomised via a computer‐generated randomisation schedule
Allocation concealment (selection bias)	Low risk	Investigators and participants were blinded to the treatments by preprinted medication code labels.
Blinding of participants and personnel (performance bias) All outcomes	High risk	States double‐blind but drugs not identical and dosage schedule differs between participants: venlafaxine taken as tablet twice daily, pregabalin as capsule once daily and carbamazepine twice daily as tablet
Blinding of outcome assessment (detection bias) All outcomes	High risk	Self‐reported outcomes from participants, but not strict blinding procedures
Incomplete outcome data (attrition bias) All outcomes	High risk	No methods for dealing with missing data specified, think they present completer analysis. Attrition Total: 33/257 (12.8%) Carbamazepine 400 mg: 7/85 (8.2%) Pregabalin 150 mg: 9/86 (10.5%) Venlafaxine 150 mg: 17/86 (19.8%)
Selective reporting (reporting bias)	High risk	Protocol not very clear, mention reporting 30th day as outcome time point but in article it's the 35th day. Did not mention work interference as outcome but have included it in paper, mention primary outcome will be measured with "PPI" and VAS but seems that PPI NR in article. Protocol registered on IRCT while recruiting participants, only 2 outcomes specified.
Other bias	High risk	Significant difference in VAS pain between groups at baseline