Videman 1984.

Methods	RCT, double‐blind
Participants	28 outpatients, 11 women, 17 men; mean age 45 years Inclusion: chronic severe low back pain, age 25 to 76 years Exclusion: pregnant or nursing women, compensation claims, haematological, renal or hepatic disease, pre‐existing radiological evidence of peptic ulcer, intolerance to indomethacin
Interventions	NSAID (i): piroxicam 20 mg/day, 6 weeks (N = 14) NSAID (ii): indometacin 75 mg/day, 6 weeks (N = 14)
Outcomes	Change of pain from baseline until 6 weeks: (i) 8.1 (ii) 9.4; no significant difference between groups. Adverse events: (i) 8 participants (ii) 10 participants
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not mentioned
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Blinding (performance bias and detection bias): All outcomes ‐ Patients All outcomes	Low risk	Patients were blinded
Blinding (performance bias and detection bias): All outcomes ‐ Care providers All outcomes	Low risk	Care providers were blinded
Blinding (performance bias and detection bias): All outcomes ‐ Outcome assessors All outcomes	Low risk	Outcome assessors were blinded
Incomplete outcome data (attrition bias): All outcomes ‐ Drop‐outs All outcomes	Low risk	Two out of 14 participants in one group were lost to follow‐up.
Incomplete outcome data (attrition bias): All outcomes ‐ ITT analysis All outcomes	High risk	Complete case analysis
Selective reporting (reporting bias)	Unclear risk	No study protocol
Similarity of baseline characteristics	Unclear risk	No baseline characteristics shown
Co‐interventions avoided or similar	Low risk	Only paracetamol as co‐intervention up to 3000 mg
Compliance acceptable	Unclear risk	Compliance not mentioned
Timing outcome assessments similar	Unclear risk	Timing was unclear