The aim of this study was to investigate work status and associated factors in patients with early rheumatoid arthritis (RA), with the emphasis on shoulder function, work-related mechanical exposure, and activity limitations related to the shoulder-arm-hand.
Patients with early RA were provided with self-report questionnaires quantifying work-related mechanical exposure and activity limitations. Shoulder function (i.e. isometric muscle strength, shoulder-arm movement, and shoulder pain), hand-grip force, and number of tender and swollen joints were assessed.
The study comprised 135 patients (103 women and 32 men), with a mean age of 48 (SD 9.6) years, a mean disease duration of 21 (SD 9.6) months, and a mean Disease Activity Score using 28 joint counts (DAS28) of 3.7 (SD 1.4). The majority (75.6%) were working full- or part-time. Work hours correlated with work-related mechanical exposure (rs = -0.34, p < 0.001) and with physical work load (rs = 0.26, p = 0.0036). Work hours also correlated with shoulder function, that is shoulder-arm movement (rs = 0.34, p < 0.0001), shoulder strength (rs = 0.25, p = 0.0032), and activity-induced shoulder pain (rs = -0.45, p < 0.0001). Significant correlations were found between work hours and hand-grip force (rs = 0.45, p < 0.0001), activity limitations related to the shoulder-arm-hand (using the Disabilities of the Arm, Shoulder and Hand Questionnaire, DASH) (rs = -0.61, p < 0.0001), and DAS28 (rs = -0.43, p < 0.0001). DASH was found to be the only significant (p < 0.001) variable to independently explain the ability of working full-time [odds ratio (OR) 0.40, 95% confidence interval (CI) 0.29-0.55 per 10 increments, area under the receiver operating characteristic (ROC) curve (AUC) 0.81, 95% CI 0.74-0.89].
Work status in early RA is associated with shoulder function and activity limitations related to the shoulder-arm-hand accentuated by work-related mechanical exposure.