Thermal characteristics of rheumatoid feet in remission: Baseline data

Objectives
Studies have shown conflicting characteristic thermographic patterns of the feet in patients with active rheumatoid arthritis (RA). However, to date no studies have compared thermographic patterns of patients with RA in remission and healthy controls. Thus this study aimed to investigate whether the thermal characteristics of the feet of RA patients, in clinical and radiological remission differ to those of healthy controls.

Methods
Using convenience sampling, RA patients were recruited upon confirmed absence of synovitis by clinical examination and musculoskeletal ultrasound. Thermal images of the feet were taken. Each foot was subdivided into medial, central, lateral, forefoot and heel regions. Subsequently, temperatures in the different regions were analyzed and compared to a cohort of healthy adults.

Results
Data from 32 RA patients were compared to that of 51 healthy controls. The Independent samples T-Test demonstrated a significant difference in temperatures in all the regions of the forefoot between RA participants versus healthy subjects (Table 1). Using the One-Way ANOVA test, no significant difference was found between all the forefoot regions (p = 0.189) of RA patients. Independent sample T-test found significant differences in all heel regions between the two groups (Table 2). One-Way ANOVA demonstrated no significant differences (p = 0.983) between the different foot regions (n = 192) of RA patients.

Conclusion
These findings suggest that RA patients in clinical and radiological remission exhibit significantly different feet thermographic patterns compared to healthy controls. This data will provide the basis for future studies to assess whether thermographic patterns change with disease activity.