Table 1

Comparison of the characteristics of the studies by Gilvarry and colleagues11 and McColl and colleagues12 with those of the OCAY13 and ORCHID14 studies

Studies by Gilvarry and colleagues11 and McColl and colleagues12OCAY13 and ORCHID14 studies
Single centreMulticentre
Not generalisableGeneralisable
Peptic ulcers found in 14% at follow upPeptic ulcers found in 2% at follow up
Baseline observation period: 3 and 6 monthsBaseline observation period: 7 days
Symptom scores locally validatedFew patients in individual centres
Symptom questionnaires not validated in each centre
Symptom assessments more difficult in multinational studies