Correlation analyses for related PRO endpoints of interest at week 16
| Endpoint 1 | Endpoint 2 | N1 | Correlation coefficient value* | |
| Tofacitinib 5 mg twice daily (N=133) | Total back pain | SF-36v2, bodily pain | 129 | –0.76 |
| Nocturnal spinal pain | SF-36v2, bodily pain | 129 | –0.69 | |
| FACIT-F total score | BASDAI fatigue | 128 | –0.66 | |
| SF-36v2, physical functioning | BASFI | 129 | –0.76 | |
| SF-36v2, mental health | EQ-5D-3L anxiety/depression | 129 | –0.69 | |
| Placebo (N=136) | Total back pain | SF-36v2, bodily pain | 131 | –0.66 |
| Nocturnal spinal pain | SF-36v2, bodily pain | 131 | –0.65 | |
| FACIT-F total score | BASDAI fatigue | 130 | –0.60 | |
| SF-36v2, physical functioning | BASFI | 131 | −0.71 | |
| SF-36v2, mental health | EQ-5D-3L anxiety/depression | 131 | −0.64 |
Data are from the week 16 analysis: data cut-off 19 December 2019; data snapshot 29 January 2020.
For SF-36v2 domains, norm-based scores were used.
*All correlations were ***p<0.001, based on Student’s t distribution (N1–2 degree of freedom) to test the null hypothesis of no correlation. Correlation coefficient values of ≤0.3, >0.30–≤0.60 and >0.60 were regarded as weakly, moderately and highly correlated, respectively.
BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; EQ-5D-3L, EuroQol-Five Dimension-Three Level Health Questionnaire; FACIT-F, Functional Assessment of Chronic Illness Therapy-Fatigue; N, number of patients in full analysis set; N1, number of patients with observation in both PRO endpoints for calculating the correlation; PRO, patient-reported outcome; SF-36v2, Short Form-36 Health Survey Version 2.