Table 2

Quality aspects related to the selection of the study population and the assignment of intervention

Epidemiologist/biostatistician
Yes % (n=178)No % (n=289)Crude OR (95% CI)Adjusted2-150 OR (95% CI)
Pre-study sample size estimation
  Yes51.139.51.6 (1.1, 2.3)1.5 (1.0, 2.3)
Inclusion/exclusion criteria
  Yes95.592.71.7 (0.7, 3.8)1.8 (0.7, 4.3)
Number of subjects asked for participation
  Yes36.532.21.2 (0.8, 1.8)1.1 (0.7, 1.7)
Number of subjects who agreed participation
  Yes25.828.00.9 (0.6, 1.4)0.8 (0.5, 1.3)
Randomisation
  Yes98.398.60.8 (0.2, 3.3)0.6 (0.1, 3.0)
Blind randomisation
  Yes/not applicable34.832.21.1 (0.8, 1.7)1.0 (0.7, 1.6)
Assessment of baseline comparability of study groups
  Yes90.685.51.6 (0.9, 3.0)1.7 (0.9, 3.3)
  • 2-150 Adjusted for number of participating centres, reporting of the source of funding, and study sample size.