Table 4 Problems identified in randomized controlled trials confirmed to be at high risk of bias and methodological adjustments with no or minor cost applied
Domains | Type of problem in original trial report | N = 121 No. (%) | Methodological adjustment | Cost |
|---|---|---|---|---|
Generation of randomization sequence | Inappropriate randomization methods including sequence generated by some rule based on date/day of admission or on hospital or clinic record number | 5 (4) | Referring to a random number table; Using a computer random-number generator Coin tossing Shuffling cards or envelopes Throwing dice Drawing of lots | No cost |
Allocation concealment | No explicitly unconcealed procedure or unsealed or nonopaque or not sequentially numbered envelopes | 10 (8) | Central allocation (including telephone, web-based and pharmacy-controlled randomization) or sequentially numbered, opaque, sealed envelopes | Minor |
Incomplete outcome data | Exclusion of patients from the analysis | 14 (11) | Intention-to-treat analysis | No cost |
Intention-to-treat analysis but inadequate missing data imputation | 2 (1) | Intention-to-treat analysis with a multiple imputation method | Minor |