Pain Characteristics Do Not Have a Significant Effect on Sedentary Behavior in Rheumatoid Arthritis

Pain and rheumatoid arthritis (RA)-related factors do not have a significant influence on sedentary behavior in patients with RA, according to study results published in Arthritis Care & Research.

In a cross-sectional study of 72 patients (65% women) with RA, the investigators aimed to identify the association between sedentary behavior and clinical pain. Clinical assessment of pain and disability was performed using validated indices and questionnaires, including the Visual Analog Scale (VAS) pain scale (0-10 cm) and the Widespread Pain Index (WPI), which assessed pain at 19 body sites. Clinical Disease Activity Index (CDAI) was used to estimate disease activity, and an activity monitors were used for 7 days to measure physical activity.

Mean age of study participants was 61.5 years and the average time since diagnosis was 17.8 years. The average CDAI score was 11.2, indicating borderline mild to moderate disease activity; he mean VAS score was 4.9; and the activity monitor data indicated that participants spent an average of 8.9 hours per day (59.9% of waking hours) in sedentary behavior. Results showed a positive association between daily sedentary time and pain intensity (effect size [r]=0.31; P <.01), and the self-reported number of painful joints (r=0.24; P <.05). Daily sedentary time was also positively associated with self-reported depression (r=0.28; P <.05), anxiety (r=0.31; P <.01), and disease activity (r=0.24; P <.05). However, no association was found with nonarticular pain.

In multivariable analysis adjusting for demographic factors and disease activity, there was no significant association found between individual pain variables and daily sedentary time (≤5% increase in variance). However, significant associations were found between daily sedentary behavior and higher disease activity (β coefficient=0.24; P =.046), daily sedentary time (β coefficient=0.622; P <.001), and higher pain intensity. Mediation analysis (Sobel’s test) determined that pain intensity mediated the relationship between disease activity and total sedentary time (2.05; bootstrap 95% CI, 0.37-4.66; P =.041).

Limitations included the cross-sectional nature of the study that may have prevented the identification of causal directionality in associations, and the fact that the study was not adequately powered for multivariable analyses.

“We found that several pain characteristics correlated with daily sedentary time but these relationships were relatively small and not maintained when other factors were accounted for in multivariable models,” the researchers concluded. “These results indicate that other non-RA related factors beyond pain and clinical characteristics are likely to be important in determining [sedentary behavior].”

Reference

O’Leary H, Larkin L, Murphy GM, Quinn K. The relationship between pain and sedentary behavior in Rheumatoid Arthritis: a cross-sectional study [published online April 11, 2020]. Arthritis Care Res (Hoboken). doi:10.1002/acr.24207