Medical statistics

Question 1

Classes of recommendations

Answer 1

Class I: evidence or general consensus that treatment is beneficial

Class II: conflicting evidence or divergence of opinion on benefits of intervention

a: weight of evidence overall is in favour of treatment
b: usefulness of intervention is less well-established

Class III: evidence or general agreement that intervention is not beneficial and possibly harmful

Question 2

Class 1 recommendation

Answer 2

Class 1: evidence or general consensus that treatment is beneficial

Therefore, recommendation is usually that treatment is indicated

Question 3

Class 2 recommendation

Answer 3

Class II: conflicting evidence or divergence of opinion on benefits of intervention

a: weight of evidence overall is in favour of treatment
- therefore, a recommendation is that treatment SHOULD be considered

b: usefulness of intervention is less well-established
- therefore, a recommendation is that treatment MAY be considered

Question 4

Class 3 recommendation

Answer 4

Class III: evidence or general agreement that intervention is not beneficial and possibly harmful

Therefore, treatment is NOT recommended

Question 5

LEVELS of evidence

Answer 5

Level A: data from multiple RCTs

Level B: data from single RCT

Level C: data from small studies, retrospective studies, registries or expert consensus