Univariable and multivariable metaregression analysis of characteristics to explain heterogeneity of prevalence of extra-articular manifestations in patients with AS
| AAU | Psoriasis | IBD | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Univariable | Multivariable* | Univariable | Multivariable† | Univariable | Multivariable‡ | |||||||
| Variable | β (95% CI) | p Value | β (95% CI) | p Value | β (95% CI) | p Value | β (95% CI) | p Value | β (95% CI) | p Value | β (95% CI) | p Value |
| Clinical variables | ||||||||||||
| Disease duration, year | 0.06 (0.05 to 0.08) | <0.01 | 0.05 (0.03 to 0.06) | <0.01 | 0.02 (−0.01 to 0.04) | 0.14 | – | – | 0.02 (0.00 to 0.04) | 0.04 | – | – |
| % women | 0.01 (0.00 to 0.02) | 0.18 | – | – | −0.01 (−0.03 to 0.02) | 0.64 | – | – | 0.02 (0.01 to 0.03) | 0.02 | 0.02 (0.00 to 0.03) | 0.05 |
| % HLA-B27+patients | 0.01 (0.00 to 0.02) | 0.09 | – | – | 0.00 (−0.01 to 0.02) | 0.58 | – | – | −0.01 (−0.02 to 0.01) | 0.28 | – | – |
| Geographical area | ||||||||||||
| Europe | Reference | – | Reference | – | Reference | – | Reference | – | Reference | – | Reference | – |
| North America | 0.27 (−0.04 to 0.58) | 0.08 | 0.17 (−0.10 to 0.44) | 0.21 | −0.44 (−0.85 to −0.03) | 0.04 | −0.44 (−0.85 to −0.03) | 0.04 | 0.05 (−0.32 to 0.43) | 0.78 | 0.15 (−0.22 to 0.51) | 0.43 |
| Latin America | −0.51 (−0.85 to −0.15) | <0.01 | −0.65 (−1.00 to −0.30) | <0.01 | −0.06 (−1.33 to 1.21) | 0.93 | −0.06 (−1.33 to 1.21) | 0.93 | 0.32 (−0.32 to 0.96) | 0.33 | 0.40 (−0.23 to 1.03) | 0.21 |
| Asia | −0.42 (−0.64 to −0.19) | <0.01 | −0.22 (−0.45 to −0.00) | 0.05 | −1.33 (−2.09 to −0.57) | <0.01 | −1.33 (−2.09 to −0.57) | <0.01 | −0.96 (−1.44 to −0.49) | <0.01 | −0.80 (−1.29 to −0.32) | <0.01 |
| Middle East | −0.64 (−0.97 to −0.30) | <0.01 | −0.38 (−0.67 to −0.09) | 0.01 | −1.03 (−1.73 to −0.32) | <0.01 | −1.03 (−1.73 to −0.32) | <0.01 | −0.03 (−0.64 to 0.58) | 0.92 | −0.01 (−0.61 to 0.59) | 0.98 |
| Australia | −0.76 (−1.90 to 0.38) | 0.19 | –§ | – | – | – | – | – | – | – | – | – |
| Methodological variables | ||||||||||||
| Risk of bias criteria | ||||||||||||
| Sampling frame¶ | −0.22 (−0.47 to 0.03) | 0.09 | – | – | −0.37 (−0.80 to 0.05) | 0.08 | – | – | −0.21 (−0.64 to 0.23) | 0.35 | – | – |
| Case definition for AS¶ | −0.08 (−0.31 to 0.14) | 0.48 | – | – | −0.20 (−0.58 to 0.19) | 0.32 | – | – | 0.02 (−0.31 to 0.36) | 0.89 | – | – |
| Random selection¶ | −0.22 (−0.46 to 0.02) | 0.07 | −0.24 (−0.43 to −0.04) | 0.02 | −0.12 (−0.50 to 0.25) | 0.53 | – | – | 0.06 (−0.26 to 0.38) | 0.70 | – | – |
| Case definition for EAM¶ | 0.00 (−0.20 to 0.20) | 0.99 | – | – | −0.08 (−0.43 to 0.26) | 0.64 | – | – | −0.26 (−0.57 to 0.05) | 0.10 | – | – |
| Study design | ||||||||||||
| Cross-sectional | Reference | – | – | – | Reference | – | – | – | Reference | – | – | – |
| Prospective cohort | 0.27 (−0.12 to 0.66) | 0.11 | – | – | 0.27 (−0.31 to 0.85) | 0.37 | – | – | 0.25 (−0.23 to 0.72) | 0.31 | – | – |
| Retrospective cohort | −0.20 (−0.45 to 0.05) | 0.12 | – | – | 0.46 (0.02 to 0.90) | 0.04 | – | – | 0.18 (−0.23 to 0.59) | 0.11 | – | – |
| Case-control study | 0.75 (−0.35 to 1.86) | 0.19 | – | – | 0.02 (−0.81 to 0.84) | 0.96 | – | – | 0.36 (−0.42 to 1.14) | 0.37 | – | – |
| Intervention study | 0.20 (−0.10 to 0.49) | 0.19 | – | – | 0.48 (0.07 to 0.89) | 0.02 | – | – | 0.11 (−0.29 to 0.52) | 0.58 | – | – |
| Sample size | 0.00 (0.00 to 0.00) | 0.13 | – | – | 0.00 (0.00 to 0.00) | 0.48 | – | – | 0.00 (0.00 to 0.00) | 0.62 | – | – |
Parameters with a p value >0.30 in univariable analysis were entered in the multivariable model and removed in order of significance if p>0.05 (backward procedure).
*Multivariable model of AAU was based on 119 studies.
†Multivariable model of psoriasis was based on 56 studies.
‡Multivariable model of IBD was based on 65 studies.
§The study on prevalence of uveitis from Australia was excluded from multivariable analysis because data on disease duration were missing.
¶Low risk of bias versus possible or unknown risk of bias. The criterion on response rate was not considered because too many scores were not reported.
AAU, acute anterior uveitis; AS, ankylosing spondylitis; EAM, extra-articular manifestation; HLA-B27,Human Leukocyte Antigen-B27; IBD, inflammatory bowel disease.