Individual- and country-level health inequalities exist in people with SpA

After taking other factors into account, women and people with lower levels of education have worse disease activity.

Spondyloarthritis (often shortened to SpA) is an umbrella term for several conditions that share many features and symptoms. Thesec onditions include ankylosing spondylitis, psoriatic arthritis and reactive arthritis. Spondyloarthritis can be classified as axial or non axial (peripheral), according to which joints in their body are affected. Axial disease affects the spine. Peripheral disease affects other joints in the body, such as the hands, shoulders, knees or feet. Ankylosing spondylitis (often shortened to AS) is the most common type of axial spondyloarthritis. Ankylosing spondylitis mainly affects the spine and the sacroiliac joints (in the back part of the pelvis), causing back pain and stiffness. In advanced stages of the disease, new bone formation can cause parts of the joints to fuse in a fixed immobile position.

Health is influenced by a number of factors. These include a person’s individual characteristics, genetics and behaviour, as well as their socioeconomic status and physical environment. Previous studies in other rheumatic diseases have shown that socioeconomic status at both an individual- and country level can have a strong impact on disease outcomes.

What did the authors hope to find?
The authors hoped to find out whether there are links between a person’s socioeconomic status (at both an individual and country level) and their disease activity and physical function. They also hoped to find out if the use of certain types of medicine called bDMARDs (also called biologics) have any impact on the relationship.

Who was studied?
The study included 3,370 people with spondyloarthritis from 22 countries. The average age was 43 years, and two-thirds of the people taking part were men. Primary education was the highest level of educational achievement for 12% of the people in the study, 44% had a secondary education diploma, and 43% were university graduates. Information about education history was missing for 1% of the people taking part.

How was the study conducted?
This was a cross-sectional observational study. This means that there was no medical intervention. Instead, people with spondyloarthritis and their rheumatologist filled in a questionnaire, and information about medical history and lifestyle was collected in a database. This information allowed researchers to investigate certain links or risks.

What were the main findings of the study?
The study found that there are inequalities among people with spondyloarthritis, both at an individual- and a country-level. Overall, women and people with a lower level of education had worse disease activity and worse physical function than men or people with higher levels of education. People in less socioeconomically developed countries had higher disease activity, but they reported similar physical function to people in more developed countries. The use of bDMARDS did not have an effect on the relationship between lower socioeconomic status and higher disease activity.

Are these findings new?
Yes. While we knew this for some other rheumatic diseases, it hasn’t been shown before for people with spondyloarthritis. In comparison to the study with people with RA, the absolute differences seem smaller. Also, in that study the use of bDMARDs did suggest a possible pathway linking lower social economic status to higher disease activity.

What are the limitations of the study?
In cross-sectional studies like the one here we have to be careful how we draw conclusions about cause and effect. Additionally, defining countries by their HDI and GDP is quite arbitrary and only allows very general patterns to be seen. The authors think it would be useful to have information about certain cultural aspects such as expectations, stress, and family support, or information about access to and quality of care in different countries. Additional information like this would help to explain the inequalities more.

What do the authors plan on doing with this information?
This study is one of several exploring how socioeconomic differences affect disease outcomes in people with rheumatic diseases. The information collected will help to raise awareness and argue for more equality in care and heath.

What does this mean for me?
If you have spondyloarthritis or another rheumatic disease, there are many different factors which can affect your disease and the care that you receive. Some of these apply to you as an individual, and some are because of the country or region you live in.

Although there are many elements that may be outside your control, there are also things you can do to help understand and manage your disease – for example, by maintaining a healthy lifestyle. If you would like to know more about staying fit and well, please talk to your doctor.

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Date prepared: July 2019
Summary based on research article published on: 23 January 2019
From: Putrik P. et al. Individual-level and country-level socioeconomic determinants of disease outcomes in SpA: multinational, cross-sectional study (ASAS-COMOSPA). Ann Rheum Dis 2019;78:466–493. doi:10.1136/annrheumdis-2018-214259

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