Predel 2019.

Methods	RCT; randomised, double‐blind, multicentre, multicountry, parallel‐group design (3 groups). Randomisation using an interactive‐response technology, with a randomisation list in blocks (5 per block; 2:2:1 ratio). Follow‐up: 8 to 10 days. Outcome assessments at day 2, 4, 6, and 8 to 10 days
Participants	Population and setting: 635 participants with acute back or neck pain presenting to 19 sites in Germany or Russia Inclusion criteria: aged 18 or above, acute back or neck pain (duration > 24 hours but < 21 days) resulting in pain on movement (POM) score of 5 or higher (0 to 10 NRS) for at least one of five standardized POM procedures Exclusion criteria: history of three or more episodes of back or neck pain in the last 6 months, or if they had chronic back or neck pain (defined as pain for three weeks or longer), if they had pain due to an identifiable cause, back or neck surgery, or rehabilitation in the last 12 months, use of prohibited medication (including any anti‐inflammatory drugs, hepinaroids, or muscle relaxants) within 3 days prior to study entry
Interventions	NSAID (i): ibuprofen (400 mg) and caffeine (100 mg; oral), 3 times daily for 5 days NSAID (ii): ibuprofen (400 mg; oral), 3 times daily for 5 days Reference treatment (iii): placebo (oral), 3 times daily for 5 days
Outcomes	Pain on movement (NRS) between baseline and the morning of day 2. Safety and tolerability measures. Global assessment of efficacy. Pain at rest (NRS). Disability (ODI)
Notes	1. Mixed population of participants with neck and back pain. The group of back pain participants for the relevant comparison of NSAID (NSAID (ii); N = 140) versus placebo (reference treatment (iii); N = 67) was N = 207. The results of these two groups were not compared separately for the subgroup of back pain (only NSAID (i) vs NSAID (ii), and NSAID (i) vs reference treatment (iii) 2. We contacted the corresponding author to ask for detailed results of the subgroup analysis of back pain participants in this group (22 January 2020)