Inflammation correlates with PROs in early RA

In the early phases inflammatory variables directly correlate with the PGA across different disease activity states

Rheumatoid arthritis is a chronic inflammatory disease that affects a person’s joints, and may cause pain and disability. Rheumatoid arthritis can affect people of all ages, but it most often starts between the ages of 40 and 60. Rheumatoid arthritis is more common in women than men.

Patient-reported outcomes (often shortened to PROs) explore a person’s perspective about their disease, and offer unique information on an individual’s symptoms and disease impact. PROs such as the Patient Global Assessment (PGA) are included in the definition of disease activity and remission for people with rheumatoid arthritis, and are included in measures to guide treatment decisions. However, challenges exist when trying to include PROs in everyday clinical practice. For example, it is not understood how well PROs align with inflammation and other measures of health. Some studies in people who have had their rheumatoid arthritis for a long time have suggested that PROs are mainly driven by emotional and personal factors rather than by disease activity, and are therefore unlikely to change with immunosuppressive therapy. In contrast, in the early stages of rheumatoid arthritis before people develop chronic pain or functional limitations, it is thought that PROs might be more directly affected by a person’s underlying levels of inflammation.

The authors wanted to explore how inflammation affects people’s PGA results in different stages of the disease (early compared to established rheumatoid arthritis), and in different groups of people, such as those with certain autoantibodies including rheumatoid factor or anti-citrullinated protein antibodies (also called RF and ACPA).

The study looked at 1,412 people with rheumatoid arthritis at different stages of the disease. This included 801 people with new-onset disease, and 611 people who had been diagnosed with rheumatoid arthritis for at least 5 years.

The study used data from three groups of people. The first was the early disease group, which included people who were referred to an early arthritis clinic, and followed for 2 years. The second and third groups were people with longer disease duration, from two different clinics in Italy.

The authors used the information collected to calculate the correlation or alignment of PGA scores with
measures of a person’s underlying inflammation, such as the number of swollen joints.

The results indicate that the significance of the PGA score in people with rheumatoid arthritis varies in relation to the duration of the disease and a person’s autoantibody status. In established disease the PGA score is mainly driven by chronic pain and functional disability. However, in the early stages of arthritis a person’s perception is also significantly influenced by their inflammation.

The authors also found that the inflammatory correlates of the PGA are more pronounced and persistent
in autoantibody-positive patients. In contrast, in people with autoantibody-negative disease, the PGA loses its association with inflammation soon after disease onset.

Yes. To the best of the authors’ knowledge, this study is the first to analyse the inflammatory correlates of PGA in people with early rheumatoid arthritis. For the first time, it has been shown that the significance of PGA can vary in relation to disease duration and autoantibody status.

There are some limitations. PGA is usually assessed using a visual scale, but the wording on these varies widely, and it is possible that different formulations and scales might affect the results. Also, the study did not record variables such as fatigue, anxiety, depression, and other comorbidities, which prevents assessment of all possible associations.

This study confirms that PGA is influenced by a number of factors that may vary over time and in relation to certain disease characteristics. There is some disagreement between rheumatologists about the inclusion of PGA in the definition of remission, as well as around the thresholds in the scores that guarantee good functional and structural outcomes. The authors are now investigating whether there are different thresholds of the PGA that are capable of identifying sustained suppression of inflammation and function in people with early rheumatoid arthritis.

If you have rheumatoid arthritis, your healthcare provider may have asked you to rate the activity of your disease on a scale of 0 to 100, considering 0 as disease in excellent control and 100 as disease at maximum activity. The value you give is then entered into a tool with other disease activity variables that together define the disease state and possibly the need to increase immunosuppressive therapy. Each individual person’s perception of the disease can be challenging to interpret, and may depend on different factors. The data from this study confirm the importance of the PGA in assessing disease activity and guiding treatment choices, particularly in the early stages of the disease and in those with disease-specific antibodies. In the future, it is possible that the importance of PGA in defining disease activity will vary on a case-by-case and individual basis.

If you have any concerns about your disease or its treatment, you should talk to your doctor.

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Date prepared: August 2022
Summary based on research article published on: 27 May 2022
From: Bugatti S, et al. Inflammatory correlates of the Patient Global Assessment of Disease Activity vary in relation to disease duration and autoantibody status in patients with rheumatoid arthritis. Ann Rheum Dis 2022;81:x–x. doi:10.1136/annrheumdis-2022-222436

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