Critical appraisal:Henderson MA, Burmeister BH, Ainslie J, Fisher R, Di Iulio J, Smithers BM, et al 2015 6

Risk of bias assessment: Randomised Controlled Trial (Cochrane risk of bias tool)

Random sequence generation

Describe the method used to generate the allocation sequence in sufficient detail to allow an assessment of whether it should produce comparable groups.

Telephone call to the trial centre by minimisation with a random component.

What was the risk of bias from the random sequence generation?

Low

Allocation concealment

Describe the method used to conceal the allocation sequence in sufficient detail to determine whether intervention allocations could have been foreseen in advance of or during, enrolment.

Telephone call to the trial centre (central allocation)

What was the risk of bias from the allocation concealment?

Low

Blinding

Describe all measures used, if any, to blind outcome assessors from knowledge of which intervention a participant received. Provide any information relating to whether the intended blinding was effective.

Patients and those assessing outcomes were not masked to treatment allocation, however the identity of the assigned treatment groups were unknown to anyone until assignment, and outcomes were not likely to be influenced by blinding.

What was the risk of bias from the blinding of participants and personnel and outcome assessors?

Unclear

Incomplete outcome data

Describe the completeness of outcome data for each main outcome, including attrition and exlusions from the analysis. State whether attrition and exclusions were reported, the numbers in each intervention group (compared with total randomized participants), reasons for attrition/exclusions where reported, and any re-inclusions in analyses performed by the review authors.

No response

What was the risk of bias from incomplete outcome data?

Low