A comparison of thermographic characteristics of the hands and wrists of rheumatoid arthritis patients and healthy controls

Thermal imaging has been applied to detect possible temperature variations in various rheumatic disorders. This study sought to determine whether rheumatoid arthritis (RA) patients without active synovitis in their hands exhibit different baseline thermographic patterns of the fingers and palms when compared to healthy individuals. Data from 31 RA patients were compared to that of 51 healthy controls. The RA patients were recruited upon confirmed absence of synovitis by clinical examination and musculoskeletal ultrasound. Participants underwent medical infrared imaging of the regions of interest (ROIs). Significant differences were found between the mean temperatures of the palm regions (29.37 °C (SD2.2); n = 306) and fingers (27.16 °C (SD3.2); n = 510) of the healthy participants when compared to the palm regions (31.4(SD1.84)°C; n = 186) and fingers (30.22 °C (SD2.4); n = 299) of their RA counterparts (p = 0.001), with the latter group exhibiting higher temperatures in all ROIs. Logistic regression models confirm that both palm and finger temperature increase significantly in RA without active inflammation. These innovative findings provide evidence that baseline thermal data in RA differs significantly from healthy individuals. Thermal imaging may have the potential to become an adjunct assessment method of disease activity in patients with RA.