Impact of sex, age, body mass index and handedness on finger joint space width in patients with prolonged rheumatoid arthritis using computer-aided joint space analysis

To evaluate the associations between sex, age, body mass index (BMI) and handedness regarding the radiogeometric detectable joint space distances of the finger articulations in patients suffering from a prolonged course of rheumatoid arthritis (RA). The joint space widths were measured by a new available Computer-aided joint space analysis (CAJSA); 128 patients with RA underwent computerized semi-automated joint space analysis of joint space distances at the metacarpal–phalangeal articulation (JSD–MCP II–V), proximal–interphalangeal joint (JSD–PIP II–V) and distal–interphalangeal joint (JSD–DIP II–V) based on digitally performed radiographs of the hand (Radiogrammetry Kit, Version 1.3.6; Sectra; Sweden). The joint space distance (JSD) of each articulation was expressed as JSD total in millimeter. The patient cohort was differentiated for gender, age, handedness and BMI (BMI < 20; BMI 20–25, BMI > 25). JSD revealed a significant age-related narrowing of 24.8% (JSD–MCP), 22.6% (JSD–PIP) and 28.7% (JSD–DIP) between the ages of 20 and 79. Additionally, males showed a significantly wider JSD compared to the female cohort for all age groups. All JSD-distances were varied between the right and left hand. The JSD–MCP demonstrated significant differences regarding the BMI groups. In contrast to JSD–MCP an effect of the BMI on measurements of JSD–PIP and JSD–DIP could not be observed. These influences must be differentiated from disease-related alterations caused by RA.