Table A7. Risk of Bias Among Randomized Controlled Trials for Comparison of Oral Vitamin B12 and Parenteral Vitamin B12.
| Author, Year | Allocation Concealment | Blinding | Complete Accounting of Patients and Outcome Events | Selective Reporting Bias | Other Limitations |
|---|---|---|---|---|---|
| Castelli et al, 2011 (71) | No limitations | Limitationsa | No limitations | No limitations | Limitationsb |
| Bolaman et al, 2003 (69) | No limitations | Limitationsa | Limitationsc | Limitationsd | No limitations |
| Kuzminski et al, 1998 (68) | Limitationse | Limitationsa | Limitationsc | No limitations | No limitations |
a
It is impossible to blind this randomized controlled trial because participants were randomized to oral or injected vitamin B12; thus it is impossible to disguise or hide the intervention.
b
This study was funded and conducted by the manufacturer of the oral vitamin B12 supplement.
c
An intent-to-treat analysis was not reported.
d
The primary end point was reported to be signs and symptoms of anemia; however, no detail was given to describe the signs and symptoms of anemia in the results.
e
The randomization process was not described.