Work status in patients with early rheumatoid arthritis: emphasis on shoulder function and mechanical exposure

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.