Characteristics of included cohort studies (n=5)
| Author, year of study, location | Study population, sample size | Demographics and disease characteristics | BMI measure | Disease activity measure(s) | Covariates adjusted for |
|---|---|---|---|---|---|
| Ottaviani40 2012 France | AS N=155 | Age: 43.1 (35.0–51.8) years Male: 63.3% HLA-B27: 64.9% Disease duration: 8.0 (3.0–12.0) Biological use: All started on infliximab | Categorical BMI Normal: <25 kg/m2 Overweight: 25–30 kg/m2 Obese: >30 kg/m2 | Baseline: BASDAI TNFi treatment response: BASDAI50 Follow-up: 6 months | Age and gender |
| Micheroli41 2017 Switzerland | axSpA N=624 | Age: 39.4±11.6 years Male: 62.2% HLA-B27: 78.1% Disease duration: 13.0±10.9 years Biological use: All started on TNFi | Categorical BMI Normal: 18.5–25 kg/m2 Overweight: 25–30 kg/m2 Obese: >30 kg/m2 | Baseline: ASDAS BASDAI TNFi treatment response: ASAS40 BASDAI50 ASAS-PR ASDAS-CII ASDAS<2.1 ASDAS<1.3 ASDAS-MI Follow-up: 1 year ±6 months | Age, gender, BASDAI, BASMI, HLA-B27 status, nr-axSpA, elevated CRP, exercise, smoking |
| Rosas42 2017 Spain | AS N=57 | Age: 47±10 years Male: 65% HLA-B27: 77% Disease duration: NA Biological use: All started on adalimumab | Categorical BMI Normal: <25 kg/m2 Overweight: 25–30 kg/m2 Obese: >30 kg/m2 | Baseline: ASDAS BASDAI TNFi treatment response: ASDAS ≤2.1 BASDAI ≤4 Follow-up: at least 3 months | NA |
| Al-Osami43 2018 Iraq | AS N=170 | Age: 36.1±9 years Male: 92.9% HLA-B27: 40% Disease duration: NA Biological use: All starting infliximab | Categorical BMI Normal: 20–25 kg/m2 Overweight: 25–30 kg/m2 Obese: >30 kg/m2 | Baseline: BASDAI TNFi treatment response: BASDAI50 | NA |
| Ancuta44 2018 Romania | AS N=190 | Age: NA Male: NA HLA-B27: NA Disease duration: NA Biological use: All starting TNFi | Categorical BMI Normal: 18.5–25 kg/m2 Overweight: 25–30 kg/m2 Obese: >30 kg/m2 | Baseline: ASDAS (values NA) BASDAI (values NA) TNFi treatment response: ASDAS>1.2 improvement BASDAI>1.2 improvement Low disease activity (BASDAI<3, ASDAS<1.2) Remission (BASDAI<1, ASDAS<1.3) Follow-up: 1 year | Age, gender, disease activity at baseline, disability at baseline, high CRP, smoking |
ASAS, Assessment in SpondyloArthritis International Society; ASAS-PR, ASAS criteria for partial remission; ASAS40, 40% improvement in ASAS criteria; ASDAS, Ankylosing Spondylitis Disease Activity Score; ASDAS-CII, clinically important improvement in ASDAS (change of ≥1.1 between baseline and follow-up); ASDAS<2.1, proportion of patients achieving an ASDAS <2.1 (reflecting moderate disease activity); ASDAS<1.3, proportion of patients achieving an ASDAS <1.3 (corresponding to inactive disease); ASDAS-MI, major improvement in ASDAS (change of ≥2.0); BASMI, Bath Ankylosing Spondylitis Metrology Index; BASDAI-50, 50% improvement in BASDAI; BMI, body mass index; CRP, C reactive protein; TNFi, tumour necrosis factor inhibitor.