Session Information
Date: Sunday, November 8, 2015
Session Type: ACR Poster Session A
Session Time: 9:00AM-11:00AM
Background/Purpose:
In RA, previous studies observed inequalities across countries as well as individual level socio-economic factors, and unequal uptake of biologic DMARDs (bDMARDs) played an important role in these inequalities. It is not known whether the same pattern is present for patients with spondyloarthritis (SpA). Our objectives were to assess (1) independent associations of country level and individual socio-economic determinants of health in patients with SpA and (2) if confirmed, whether this relation is mediated by uptake of bDMARDs.
Methods:
Data from the cross-sectional multinational (22 countries) study Comorbidities in Spondyloarthritis (COMOSPA) was used. ASDAS-CRP and BASFI were the outcomes. First, the contribution of individual socio-economic factors (age, gender, and education) was explored, adjusting for BMI, comorbidities, presence of extra-articular manifestations and axial SpA. Next, country of residence (separate variable for each country) or country’s welfare was added to the model. Country’s welfare was defined as Gross Domestic product (GDP) per capita (low, medium or high). Multivariable linear regression models were used. Interactions between (1)education (2)age and (3)gender with GDP were tested. The mediating role of uptake of bDMARDs in the relationship between education and ASDAS or GDP and ASDAS was explored by testing indirect effects.
Results:
3984 patients from 22 countries worldwide (41 to 337 subjects/country) were included. Mean age was 44 yrs. (SD14), 65% males, 13% had primary and 45% secondary education, 83% axial SpA. Mean ASDAS and BASFI were 2.4 (SD1.1) and 3.0 (SD2.7), respectively. Five to 68% of patients were currently treated with bDMARDs. Females (vs. males) had higher BASFI (β=0.70 [95%CI 0.54;0.86]) while gender was not relevant for ASDAS and effect of age was negligible for both outcomes. Lower educated individuals had higher ASDAS and BASFI (β=0.21 [0.09;0.33] and β=0.60 [0.37;0.85], respectively) (Table). Large country differences were observed after adjusting for individual confounders. Low GDP (vs. high GDP) was associated with higher ASDAS (β=0.70 [0.60;0.79]) but lower BASFI (β=-0.21 [-0.42;-0.01] (Table). No interactions were detected. Current uptake of bDMARDs did not mediate relationship between education or GDP with ASDAS.
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Table. Association between individual and country level (GDP) factors with ASDAS and BASFI. Results of multivariable linear regression model (β [95%CI]). |
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ASDAS |
BASFI |
|
|
Age, years |
-0.01 [-0.01;-0.00] |
0.02 [0.01;0.02] |
|
Gender (female vs male) |
0.04 [-0.04;0.12] |
0.70 [0.54;0.86] |
|
Education Low education vs. University diploma |
0.21 [0.09;0.33] |
0.60 [0.37;0.85] |
|
Secondary education vs. University diploma |
0.11 [0.04;0.19] |
0.60 [0.44;0.75] |
|
Rheumatic diseases comorbidity index (RDCI, 0-9) |
0.13 [0.09;0.17] |
0.50 [0.42;0.57] |
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Disease duration, years |
Not included |
0.01 [0.00;0.02] |
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Body-mass index (BMI ) Underweight vs normal |
0.23 [0.00;0.46] |
-0.09 [-0.54;0.37] |
|
Overweight vs normal |
0.11 [0.02;0.19] |
0.23 [0.06;0.40] |
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Obesity vs normal |
0.28 [0.18;0.39] |
0.59 [0.38;0.80] |
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Presence of axial SpA (yes vs no) |
0.16 [0.06;0.26] |
1.12 [1.05;1.19] |
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GDP Middle vs High GDP |
0.10 [0.01;0.20] |
-0.27 [-0.47;-0.08] |
|
Low vs High GDP |
0.70 [0.60;0.79] |
-0.21 [-0.42;-0.01] |
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GDP – Gross Domestic Product in int.$ ASDAS – Ankylosing Spondylitis Disease Activity Score; BASFI – Bath Ankylosing Spondylitis Function Indices |
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Conclusion:
Lower education was associated with worse disease activity and function in SpA. In addition, even after adjusting for individual factors, substantial differences in these outcomes remained between countries. Interestingly, low GDP societies had higher objectively measured disease activity (ASDAS), but appeared to score slightly better on the more subjective assessment of physical function (BASFI). Relationship between low socio-economic status (individual or country level) and higher disease activity could not be attributed to lower uptake of biologic DMARDs.
To cite this abstract in AMA style:
Putrik P, Ramiro S, Keszei A, Dougados M, Moltó A, van der Heijde D, Landewé RBM, Boonen A. Are Individual or Country Level Socio-Economic Determinants Related to Disease Activity and Self-Reported Physical Function in Patients with Spondyloarthritis – Results from Multi-National Cross-Sectional Study Comospa [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/are-individual-or-country-level-socio-economic-determinants-related-to-disease-activity-and-self-reported-physical-function-in-patients-with-spondyloarthritis-results-from-multi-national-cross-secti/. Accessed .« Back to 2015 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/are-individual-or-country-level-socio-economic-determinants-related-to-disease-activity-and-self-reported-physical-function-in-patients-with-spondyloarthritis-results-from-multi-national-cross-secti/