Pirbudak 2003.

Study characteristics
Methods	Design: parallel Duration: 9 months Assessment: baseline, 2 weeks, 6 weeks, 3 months, 6 months, post‐intervention Country: Turkey
Participants	Pain condition: low back pain Population: people aged > 35 years with chronic low back pain Minimum pain intensity: no Inclusion criteria Chronic low back pain of at least 3 months' duration not responding to other modalities of conservative management Exclusion criteria Severe clinical ailments such as cardiac disease and chronic renil failure Total participants randomised: 92 Age in years (mean, SD): 49.1 Gender: 62/92 were female Pain duration in months (median, range): 16.5 (6‐48)
Interventions	Epidural injection + placebo n = 46 Inert placebo Epidural injection consisted of 10 mL of betamethasone dipropionate (10 mg) + betamethasone sodium phosphate (4 mg) + bupivacaine (0.25%). Injections were repeated at the end of the 2nd week if the improvement was partial and at the end of the 6th week if there was still incomplete recovery from pain. Participants took placebo tablets for 9 months in addition to the injection. Epidural injection + amitriptyline (10‐50 mg) n = 46 TCA Amitriptyline flexibly dosed between 10 and 50 mg/day depending upon tolerance Epidural injection consisted of 10 mL of betamethasone dipropionate (10 mg) + betamethasone sodium phosphate (4 mg) + bupivacaine (0.25%). Injections were repeated at the end of the 2nd week if the improvement was partial and at the end of the 6th week if there was still incomplete recovery from pain. Participants took amitriptyline tablets for 9 months in addition to the injection.
Outcomes	Pain intensity Physical function
Missing data methods	Unclear
Funding source	NR
Conflicts of interest	NR
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	Says double‐blinded, but doesn't specify information about the medication
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Self‐reported outcomes from participants, but unsure of blinding procedures
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No missing data methods and no withdrawal data reported, seems like all participants completed but unclear
Selective reporting (reporting bias)	Unclear risk	No protocol or trial registration found
Other bias	Low risk	No other sources of bias were identified.