RRR constant | ARR constant | Mixed model | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Placebo event rate(%) | RRR = 50% | RRR = 75% | ARR = 15% | ARR = 25% | Intervention event rate = 5% | ||||||
Patient group | 2 sided | 1 sided | 2 sided | 1 sided | 2 sided | 1 sided | 2 sided | 1 sided | 2 sided | 1 sided | |
Early RA, disease duration <2 years; late RA: disease duration ⩾2 years; RRR, relative risk reduction = (1−(negative event rate intervention group – negative event rate placebo group)×100); ARR, attributive risk reduction = (negative event rate placebo group – negative event rate intervention group); event rate, percentage of patients with progression of joint damage larger than smallest detectable change (SDC) based on the chronological Sharp/van der Heijde change-score. | |||||||||||
*ARR 25% not feasible owing to a placebo event rate <25%, estimated sample size based on the maximal ARR (18%). | |||||||||||
Early RA | |||||||||||
Regardless of baseline damage | 18 | 227 | 179 | 84 | 66 | 60 | 48 | 37* | 29* | 94 | 74 |
Medium + high baseline damage, score ⩾4 | 35 | 97 | 76 | 36 | 28 | 135 | 106 | 24 | 19 | 25 | 20 |
High baseline damage, score ⩾21 | 64 | 34 | 27 | 13 | 10 | 168 | 132 | 40 | 32 | 7 | 5 |
Late RA | |||||||||||
Regardless of baseline damage | 36 | 92 | 73 | 34 | 27 | 138 | 109 | 25 | 20 | 23 | 18 |
Medium + high baseline damage, score⩾4 | 42 | 73 | 58 | 27 | 21 | 154 | 122 | 31 | 24 | 17 | 14 |
High baseline damage, score ⩾21 | 52 | 52 | 41 | 19 | 15 | 169 | 133 | 37 | 29 | 11 | 9 |