von Heymann 2013.

Methods	RCT, double‐blind, double‐dummy design Follow‐up time: 12 weeks. Outcome measurements: before treatment, after 3 days, between 7 and 9 days after treatment
Participants	Population: 101 participants randomised; 69 during initial 3‐arm phase, 32 during 2‐arm phase. N = 1: no treatment registered; N = 100 received treatment Setting: 5 outpatient orthopaedic or general practices in 4 different cities in Germany, between February 2003 and September 2008 (interim analysis June 2006) Inclusion criteria: people aged 18 to 55 years, presenting with acute (for < 48 hr before randomisation) LBP, and written informed consent Exclusion criteria: known intolerance to NSAID or paracetamol, occurrence of LBP or spinal manipulation for any cause within the last 3 months, known or suspected abuse of alcohol or drugs, metabolic, or malignant, or any serious organic or neurological disease, atopic diathesis, any structural disturbances of the spine (osteoporosis, scoliosis, disc herniation, spondylolisthesis, hip dysplasia, and others). Women with childbearing potential had to undertake effective contraception. For real sham manipulation, people with dysfunction of the sacroiliac joint (SIJ) were excluded (by functional and pain‐provocation tests).
Interventions	NSAID (i): Sham manipulation and Diclofenac 50 mg, t.i.d.; 7 to 9 days (N = 37) Reference treatment (ii): Spinal manipulation and diclofenac‐like placebo, t.i.d.; 7 to 9 days (N = 38) Reference treatment (iii): Sham manipulation and diclofenac‐like placebo t.i.d.; 7 to 9 days (N = 25); placebo‐arm was closed after an interim‐analysis with 69 subjects who completed the study
Outcomes	Mean change in disability (RMDQ, 0 to 24) from baseline to 7 to 9 days (SD): (i) 4.75 (4.93), (ii) 7.71 (4.88) Pain intensity 100‐mm VAS: data shown in graph. Comparison between both active treatments and placebo only, and comparison of diclofenac vs spinal manipulation Quality of life (SF‐12): data shown in graph Cumulative dose of and number of days of rescue medication taken: (i) 6.41 (10.67) and 1.92 (2.61); (ii) 2.22 (3.73) and 1.19 (1.77); no significant differences Off‐work time (days): (i) 1.80 (2.10), (ii) 1.24 (1.69); no significant differences Overall clinical impression by blinded investigator after 3 and 7 to 9 days (complete relief or improved): (i) 20/37 (54%) and 21/37 (57%); (ii) 30/35 (86%), 29/35 (83%) Adverse events: none were registered
Funding	Funding by the German Organization for Manual Medicin (Deutsche Gesellschaft fúr Manuelle Medizin, DGMM), and doctors seminar for manual spine‐ and extremities therapy (Aerzteseminar fúr Manuelle Wirbelsaeulen‐ und Extremitaetentherapie, MWE). The first author is a member of the board of DGMM. No other conflicts of interest regarding any medical measures tested.
Notes	An interim analysis was performed when 69 participants completed the study. Due to statistically significant superiority of active compared with placebo treatment, the placebo arm was closed. The trial continued with 2 active treatment groups.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	participants were randomised using a phone call to the involved and responsible Institute of Biometrics.
Allocation concealment (selection bias)	Low risk	Numbered folders and numbered boxes with the trial medication; both diclofenac and placebo prepared in an identical way. After a phone call to the biometric institute, the physician received the randomised number of the folder, allocating the subject to one of the trial arms.
Blinding of participants and personnel (performance bias) All outcomes ‐ participants	Low risk	Double‐dummy design, participants were blinded
Blinding of participants and personnel (performance bias) All outcomes ‐ careproviders	High risk	Sham manipulation could only be performed in single‐blind manner. Outcome assessment took place by another physician (blinded investigator).
Blinding of outcome assessment (detection bias) All outcomes ‐ outcome assessors	Low risk	Outcome assessment by a physician other than the one performing the spinal/sham manipulation.
Incomplete outcome data (attrition bias) All outcomes ‐ dropouts	High risk	> 20% dropouts in placebo group
Incomplete outcome data (attrition bias) All outcomes ‐ ITT analysis	Low risk	ITT analysis performed: "93 subjects were evaluable and formed the collective intention‐to‐treat (22 placebo, 36 diclofenac, 35 spinal manipulation)"
Selective reporting (reporting bias)	Low risk	Protocol is available on request in German
Similarity at baseline characteristics	Low risk	Baseline characteristics similar
Co‐interventions avoided or similar	Low risk	Paracetamol 500 mg, maximum 6 tablets a day, was used as rescue medication. No other concomitant analgesic medication, acupuncture, or homeopathy was allowed.
Compliance acceptable	Unclear risk	Protocol violation in 8/101 participants; and a lot of participants in the placebo group withdrew.
Timing outcome assessments similar	Low risk	Timing of outcome assessments similar
Other bias	Low risk	None