Was the assignment of patients to treatment randomized? And, was the randomization list concealed?
Randomisation helps ensure that patients in treatment groups are identical at the study onset in their risk of the event we are hoping to prevent. It balances groups for prognostic factors (good or bad) that if they were unequally distributed amongst the groups, could increase, decrease or nullify the effect of the therapy.
We need to check if the randomisation list has been concealed from the clinicians who entered patients into the trial. This is done so that the clinicians won't be aware of which treatment the next patient would receive.
The study that we found was randomised (which is one of the inclusion criteria for a therapy article in Best Evidence). From the original article we can see that the randomisation list was concealed and details on the randomisation process were also provided.
- Was the assignment of patients to treatment randomized? And, was the randomization list concealed?
- Was follow-up of patients sufficiently long and complete?
Were all patients analyzed in the groups to which they were randomized?
And some less important points:
- Were patients and clinicians kept blind to treatment?
- Were groups treated equally, apart from the experimental therapy?
- Were the groups similar at the start of the trial?