Translating Differing Disease Activity Scores Into a Universal Score for Rheumatologists

Measuring disease activity is a key aspect of rheumatologic care, but the creation of tools designed specifically for disease areas of interest has resulted in fragmentation and multiple disease activity scores, sometimes even just for a single disease. In an abstract presented at the European Congress of Rheumatology of the European League Against Rheumatism, researchers from France attempted to standardize activity scores of inflammatory diseases.

Not only are rheumatologists treating patients with a variety of diseases, but the different activity scores all have different maximum values. For instance, the maximum is 9 for the rheumatoid arthritis Disease Activity Score from the National Rheumatoid Arthritis Society, but the maximum score is 40 for the Polymyalgia Rheumatica Disease Activity Score.

“Normalization of these scores seems to be necessary to facilitate daily clinical practice,” the authors wrote.

In an attempt to create a universal activity score, the researchers conducted a literature review, after which they selected disease activity scores with cut off values in 4 classes: remission and low, moderate, and high disease activity. Next, they mapped the disease activity scores to a new score they developed, and finally, they created a smartphone application that would automatically convert scores from various tools to their universal score.

For the AS135 universal score that the authors created, they set the threshold values for low, moderate, and high activity states at 1, 3, and 5, respectively. By associating these thresholds with the thresholds of existing scores, it was possible to “compare the activity scores defined on different domains from different parameters by converting these scores into the AS1235 score,” they explained.

The authors analyzed a total of 1068 articles, although 599 were eventually selected and ultimately 12 scores were implemented into the app. In a situation where 2 patients have rheumatoid arthritis, but patient 1 had a score of 6.7 based on Disease Activity Score-28 and patient 2 had a score of 25 based on the Simple Disease Activity Index, the AS135 could compute that patient 1 had a universal score of 6.92 and patient 2 had a score of 4.8. Based on the thresholds, patient 1 has high disease activity and patient 2 has moderate activity.

“We have created a mobile application that allows any user to obtain in a simple way the level of disease activity, whatever the criterion used to describe it, since the application returns, in addition to the value of the activity criterion calculated from data returned by the physician, the transformation of this value into AS135 criterion and its interpretation in terms of level of activity of the pathology,” the authors concluded.

Reference

Foulquier N, Chevet B, Carvajal Alegria G, et al. Towards a universal definition of disease activity scores thresholds. Presented at: EULAR 2020; June 3-6, 2020; Abstract THU0617-HPR. https://ard.bmj.com/content/79/Suppl_1/551.1