Stratz 1990.

Methods	RCT; single‐blind, multicentre study. Randomization procedure not described. Article in German. Follow‐up time: 3‐5 days (baseline and final measurements; maximum follow‐up time 2 days after the last IM injection).
Participants	Population: 96 participants with acute LBP, 49 women, 47 men; mean age 50.8 years, aged between 16 and 78 years Setting: participants visiting four participating physicians, conducted in Germany Inclusion criteria: first episode of acute lumbago, or acute onset after a long symptom‐free period Exclusion criteria: age < 14 years, pregnancy or lactation, allergy, current use of corticosteroid or anti‐rheumatic treatment with half‐life > 24 hours, other NSAIDs or anticoagulant treatment
Interventions	NSAID (i): diclofenac‐natrium IM 3 mL (= 75mg), 1 to 3 injections (with a minimum of 16 hours between injections), 1 to 3 days (N = 47) NSAID (ii): etofenamat (Rheumon®) IM 2 mL (= 1000 mg), 1 to 3 injections (with a minimum of 16 hours between injections), 1 to 3 days (N = 49)
Outcomes	Similar amount of IM injections was needed in both groups, no significant differences. Mean pain score (11‐point NRS), at baseline and after 3 to 5 days: (i) 5.3, 2.7, (ii) 5.3, 2.4 No. of participants recovered after 3 to 5 days (therapeutic success: 'good' or 'very good'): (i) 27/47, (ii) 34/49. Not significant Adverse events: (i) 2 (none withdrew), (ii) 0 (none withdrew)
Funding	Not mentioned
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation procedure not described
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Blinding of participants and personnel (performance bias) All outcomes ‐ participants	Low risk	participants were blinded; procedure not described
Blinding of participants and personnel (performance bias) All outcomes ‐ careproviders	High risk	Careproviders were not blinded
Blinding of outcome assessment (detection bias) All outcomes ‐ outcome assessors	Unclear risk	Not mentioned
Incomplete outcome data (attrition bias) All outcomes ‐ dropouts	Low risk	Low dropout rate: 1/96 = 1%
Incomplete outcome data (attrition bias) All outcomes ‐ ITT analysis	Unclear risk	Not mentioned
Selective reporting (reporting bias)	Unclear risk	No study protocol
Similarity at baseline characteristics	Unclear risk	Baseline characteristics similar according to text, but no Table 1 available.
Co‐interventions avoided or similar	Low risk	No use of anti‐rheumatica, anti‐flogisti or analgesic medication other than study drug. No use of corticosteroids. If further treatment with oral or topical NSAIDs was necessary after injections, this was recorded. This was the case in (i) 28/47 (60%) and (ii) 23/49 (47%) of the participants.
Compliance acceptable	Low risk	1 person in group (i) (diclofenac IM) withdrew after the first injection, because of no benefit. All the others seemed to have complied to the treatment and follow‐up program.
Timing outcome assessments similar	High risk	Timing not similar; final measurements 2 days after last injection, this could be either after the first, second, or third injection.
Other bias	Low risk	None