Determinants of Work Disability in Patients with Systemic Sclerosis: A Longitudinal Study of the GENISOS Cohort

Objectives: To determine the prevalence, correlates, and predictors of work disability (WD) in the Genetics versus ENvironment In Scleroderma Outcome Study (GENISOS). We hypothesized that WD in systemic sclerosis (SSc) is a function of demographic, clinical, and psychosocial factors. Methods: Patients enrolled in the GENISOS cohort were subdivided in 3 groups: work disabled, working, and retired or homemakers. The latter group (n = 29) was excluded from further analysis. We used logistic regression analysis with a forward hierarchical variable selection strategy to investigate the independent correlates of WD at enrollment. Cox regression proportional Hazard's model with a similar variable selection strategy was utilized to determine the predictors of WD in those working at enrollment. Results: Overall, 284 patients with a mean age of 48.7 years and disease duration of 2.5 (1.6) years were enrolled into the GENISOS cohort, consisting of 83.5% female, 46.8% white, 28.9% Hispanic, and 20.4% African American. Patients were longitudinally followed in 1438 study visits. At enrollment, 124 patients (43.7%) were work disabled, whereas 131 (46.1%) were working. Lower level of education (P < 0.001), higher Medsger Lung Severity Index (P = 0.012), higher Fatigue Severity Score (P = 0.008), and less social support (P < 0.001) correlated independently with WD. Of those working at baseline, 35 (26.7%) eventually developed WD. Non-white ethnicity (P = 0.038), lower DLCO % predicted value (P = 0.038), and higher Fatigue Severity Score (P = 0.009) at enrollment independently predicted WD on follow-up visits. Conclusions: WD is a major problem among SSc patients and its prevalence is substantially higher than other rheumatic conditions. Demographic, clinical, and psychosocial factors correlate with WD cross-sectionally and predict WD longitudinally in these patients.