Friedmann 2011.

Methods	Randomised controlled trial 2‐arm parallel group design Trial duration: 14 weeks Multicentre trial with 61 centres Power calculation reported
Participants	Participants with moderate‐to‐severe osteoarthritis pain using NSAIDs or opioids were eligible 412 participants were randomised 412 participants with knee or hip osteoarthritis were reported at baseline Affected joints: 323 knees and 89 hips Number of females: 288 of 412 (70%) Mean age: 58 years
Interventions	Experimental intervention Oral extended‐release oxycodone (Remoxy), 5‐20 mg twice daily Control intervention Placebo, twice daily Treatment duration: 12 weeks Unclear whether analgesics other than study drugs allowed
Outcomes	Extracted pain outcome: global pain after 14 weeks No function outcome reported Primary outcome: change in pain intensity score
Notes	Sponsor: Pain Therapeutics, King, Pfizer
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method used to generate random sequence of allocation was not reported, so the risk of selection bias was unclear
Allocation concealment (selection bias)	Unclear risk	Method used to conceal the random sequence of allocation was not reported, so the risk of selection bias was unclear
Described as double‐blind?	Low risk	Quote: "...a double‐blind, multicenter, placebo‐controlled trial..."
Blinding of patients?	Unclear risk	It was unclear if method used to blind participants was appropriate
Blinding of physicians?	Unclear risk	Physicians were not explicitly described as blinded, so the risk of performance bias was unclear
Blinding of outcome assessors?	Unclear risk	Because outcomes were self reported, and because it was unclear whether participants were properly blinded, it was unclear whether outcome assessors were blinded
Interventions reported as indistinguishable?	High risk	Interventions were not reported as indistinguishable
Double‐dummy technique used?	Unclear risk	Description of intervention is not detailed enough to assess whether double‐dummy technique was used
Intention‐to‐treat analysis performed? Pain	High risk	2 of 205 participants excluded in experimental group, 0 of 207 participants excluded in control group
Intention‐to‐treat analysis performed? Function	Unclear risk	Not applicable, no function outcome reported