Results of mixed effects regression models with and without including the effect of publication year in the model
| Outcome | Model type | Effect for AS (95% CI) | Effect for nr-axSpA (reference: AS; 95% CI) | p Value (comparison) | Effect of publication year (per year, reference: 2008; 95% CI) | I2 (%) | Test for heterogeneity (p value) |
|---|---|---|---|---|---|---|---|
| Continuous outcome measures (SMD) | |||||||
| BASDAI (SMD) (n=23) | With diagnosis | 1.00 (0.86 to 1.13) | −0.30 (−0.58 to −0.02) | 0.03 | – | 49 | 0.007 |
| With diagnosis and publication year | 0.96 (0.83 to 1.09) | –0.14 (–0.44 to 0.16) | 0.35 | –0.038 (–0.072 to –0.004) | 40 | 0.04 | |
| BASFI (SMD) (n=24) | with diagnosis | 0.67 (0.58 to 0.76) | –0.22 (–0.41 to –0.04) | 0.02 | – | 0 | 0.44 |
| With diagnosis and publication year | 0.64 (0.55 to 0.73) | –0.08 (–0.30 to 0.13) | 0.44 | –0.028 (–0.051 to –0.005) | 0 | 0.73 | |
| Dichotomous outcome measure (OR) | |||||||
| ASAS40 response (OR) (n=19) | With diagnosis | 4.9 (3.9 to 6.3) | 0.73 (0.46 to 1.2) | 0.18 | – | 0 | 0.80 |
| With diagnosis and publication year | 4.7 (3.7 to 6.1) | 0.88 (0.51 to 1.5) | 0.66 | 0.96 (0.90 to 1.02) | 0 | 0.83 | |
AS, ankylosing spondylitis; BASDAI, Bath AS disease activity index; BASFI, Bath AS functional index; nr-axSpA, non-radiographic axial spondyloarthritis; SMD, standardised mean difference.