Requirements for applying a case-control study model and clinical significance of changes in the visual analogue scale score in abdominal pain

The framework of the study is a comparison of two groups of patient: one group formed of people affected by the pathological condition (cases) and the other constituted by people with the same features as the cases but free from the pathological condition to be analysed (controls). The crucial aspect of the design of a case–control study is that the cases are correctly selected, since the reliability of the study itself depends on this.