Brief Report: To squeeze or not to squeeze, that is the question! Optimizing the Disease Activity Score in 28 joints by adding the squeeze test of metatarsophalangeal joints in early rheumatoid arthritis

Abstract

Objective. To optimize use of the Disease Activity Score in 28 joints (DAS28) in early rheumatoid arthritis (RA) by adding the "squeeze test" of forefeet.Methods. The squeeze test is used to examine bilateral compression pain (BCP) across the metatarsophalangeal (MTP) joints. For this study, data for patients participating in the Treatment in the Rotterdam Early Arthritis Cohort study, an ongoing clinical trial that evaluates different induction therapies in patients with early RA, were randomly divided into 2 subsets. In subset 1 (149 patients and 819 disease activity assessments), the mathematical function of the DAS28-squeeze was constructed using a linear regression model with the DAS as the dependent variable and the DAS28 and squeeze test as the independent variables. A DAS28-BCP disease state was also constructed, in which DAS28 disease state categorizations were upgraded one state if the result of the squeeze test was positive. In subset 2 (153 patients and 754 assessments), concordance in disease states between the DAS28, DAS28-squeeze, and DAS28-BCP disease states was compared, using both the DAS and Boolean-defined remission criteria as reference.Results. Agreement between the DAS and the DAS28-squeeze (82%) was significantly higher than agreement between the DAS and the DAS28 (76%). When we assessed the group of patients who had arthritis of the forefeet only (22 patients and 46 assessments), overall agreement between the DAS and the DAS28 was 40%, while agreement between the DAS and the DAS28-squeeze was 59% and that between the DAS and the DAS28-BCP disease state was 65%. Furthermore, the specificities of the DAS28-squeeze and the DAS28-BCP (80% and 81%, respectively) were higher than that of the DAS28 (76%), while the sensitivities of the DAS28, DAS28-squeeze, and DAS28-BCP to identify true remission according to the Boolean criteria were 88%, 87%, and 81%, respectively.Conclusion. Adding the squeeze test of forefeet to the DAS28 has value for dependably classifying the disease state in patients with early RA.

The rheumatoid forefoot

“…Interestingly, this does not include the foot in its assessment. De Jong et al performed a study where they added a squeeze test across the MTPJs in their assessment using the DAS 28 [13]. They found that this had greater sensitivity for the assessment of disease severity in patients presenting with early RA.…”

Diagnostic values of DAS28 and DAS28-squeeze in evaluating Rheumatoid Arthritis disease

“…Recently, rheumatologists adopted the "treat to target" therapeutical protocol for treating early RA. [1][2][3][4] The main strategy of the therapy is assessing disease activity on a regular basis to achieve a certain target. In daily practice disease activity assessment is usually done with Disease Activity Score 28 (DAS28) because it is clinically applicable.…”

“…In daily practice disease activity assessment is usually done with Disease Activity Score 28 (DAS28) because it is clinically applicable. [1][2][3] DAS28 has been developed and validated using data from clinical research. Unfortunately, a valid instrument developed from a set of clinical research data is not neccesary became a valid instrument in daily practice.…”

“…This could lead to a false negative misclassification, where an active disease activity classified as in a remission state. 1,5,6 Literatures stated that up to 40% patients classified as remission by DAS28 still have feet complaints (swollen and/or tender on at least one metatarsophalangeal [MTP] joint). 1,8,10,11 Further, remission patients, according to DAS28, were also found to have a significant swollen joint counts.…”

“…1,5,6 Literatures stated that up to 40% patients classified as remission by DAS28 still have feet complaints (swollen and/or tender on at least one metatarsophalangeal [MTP] joint). 1,8,10,11 Further, remission patients, according to DAS28, were also found to have a significant swollen joint counts. 1,8,10,11 Feet complaints as an initial symptoms has been found in 60% of RA patients, and after 2 years the feet involvement prevalence decreases to 36%.…”