Professional life plays a crucial role in patients’ overall quality of life. Herein, we demonstrate that demographic, clinical, and psychosocial factors contribute to SSc-WD. To our knowledge, this is the first report on impact of SSc on the employment status in the United States. Moreover, it is the first longitudinal study examining the predictors of WD in patients with early SSc.
In addition to comprehensive demographic and clinical data, we also investigated the cross sectional and longitudinal influence of social support (ISEL), learned helplessness (AHI), coping skills (IBQ), and other previously reported psychometric correlates of WD in SSc (fatigue, HAQ and SF-36) (7
). We hypothesized that demographic, clinical, patient-reported outcomes, and psychosocial factors determine the occupational status in an individual with SSc.
Confirming previous studies (7
), we showed a high prevalence of WD in early SSc. However, the observed prevalence was higher than reports from the well-characterized Canadian Scleroderma Registry Group (46% versus 21%) (7
). This discrepancy could be explained by differences in the investigated study populations. Our patients had a higher frequency of diffuse cutaneous involvement (57% versus 48%). Furthermore, GENISOS was an incident cohort with mean disease duration of 2.5 years at enrollment, which is more likely to include patients with severe disease than a prevalent cohort. Moreover, the majority of the study population was Caucasian (90%) in the Canadian Scleroderma Registry whereas GENISOS included 53 % Non-Caucasian patients; Non-Caucasians had a higher mortality rate (3
) and were more likely to be disabled (). On the other hand, the prevalence of WD in GENISOS was lower than another study of 72 SSc patients in France (8
). Same group later reported a WD prevalence of 41% among patients with digital ulcers (9
). Differing health care policies of the investigated countries might also contribute to the observed variations in prevalence rate of WD (16
). Nevertheless, the prevalence of work disability in SSc is substantially higher than other common rheumatic conditions (10
In agreement with previous studies, demographic variables, specifically lower educational level (7
), lung involvement (9
), fatigue severity (7
), and social support were independent correlates of WD at the cross sectional level in our study. Patients with lower educational level are more likely to hold occupations that are physically demanding. Therefore, its correlation with WD is not surprising. Similar demographic variables were correlates of WD in patients with early RA (42
) and SLE (43
). Fatigue also correlated with WD in previous studies of patients with SSc (21
Confirming a recent report by Sandqvist et al.
, social support was an independent correlate of WD in the GENISOS cohort (21
). Previous studies have shown the impact of social support on disease activity, self-perceived quality of life, and occupational status in the patients with SLE (17
). Furthermore, a national longitudinal study of the overall population in the United States demonstrated that social support is an independent predictor of overall functional health (46
). These further emphasize on the pivotal role of high quality social relationships with family and friends on the patient’s work ability. Because of its modifiable nature, the independent correlation between social support and WD suggests the necessity of multifaceted psychosocial interventions to enhance the working abilities among the patients with SSc.
After follow up of 4.4 years, almost one in four patients working at enrollment (Group A) became work disabled. Using Cox proportional hazards regression model, non-Caucasian ethnicity, lung involvement (DLCO % predicted), and higher score on Fatigue Severity Scale at baseline were the independent predictors of WD in the longitudinal study.
We have previously shown that non-Caucasian patients have higher mortality in the GENISOS cohort (3
), indicating an overall less favorable prognosis (3
). The predictive significance of non-Caucasian ethnicity for development of WD might be secondary to unmeasured demographic, clinical, and psychosocial factors. Health care factors leading to disparities in access to care might also be important (49
). Non-Caucasian ethnicity was also predictive of WD development in other rheumatic diseases like SLE (50
Scleroderma pulmonary involvement, including both interstitial lung disease and pulmonary arterial hypertension, is the primary cause of SSc- related death (51
). Confirming previous results, we have shown that pulmonary involvement is also a predictor of mortality in the GENISOS cohort (3
). Therefore, it is not surprising that pulmonary involvement was associated with WD at baseline and longitudinally in the current study.
In the Scleroderma Lung Study, treatment with oral cyclophosphamide led to improvement in health-related quality of life measures along with better pulmonary function (52
). In the current study, treatment with cyclophosphamide had no significant relationship to WD. However, differences in baseline characteristics between treated and untreated groups might have blunted the treatment effect. Randomized controlled studies with long-term follow up are more appropriate to determine the effect of various medications on WD.
Fatigue is one of the most common and overlooked complaints in patients with SSc (53
). Our results confirm previous cross-sectional studies indicating that fatigue is an important contributor to WD (21
). In our study, fatigue was not only correlate (cross-sectional) but also a predictor (longitudinal) of WD. Fatigue might be partially a mediator of the effects of demographic and clinical and factors on WD. However, our analysis with successive conceptual blocks demonstrates that psychosocial factors including fatigue contribute independently to WD and are not merely mediators of demographic or clinical factors. Our findings further underscore the need for future studies focusing on pathophysiology and treatment of fatigue in SSc.
In agreement with a previous study (21
), small joint contracture was associated with WD at the univariate level. However, it was neither an independent correlate nor predictor of WD in the multivariate model. It is possible that a dichotomized variable as defined in our cohort does not capture the true severity of small joint contracture.
The GENISOS cohort includes a large number of early SSc patients from different ethnic backgrounds. The current study demonstrates the first assessment of prevalence, correlates, and predictors of WD in SSc that includes a sizable Hispanic and African American population. This enhances the generalizability of our findings. Furthermore, the comprehensive array of demographic, clinical, and psychosocial variables decreases the likelihood of missing important correlates or predictors.
However, the current study had some limitations. The majority of study subjects were recruited from tertiary medical centers, which can introduce referral bias (toward more severe cases). Detailed information on job descriptions and demands was not available in the GENISOS cohort. Therefore, we could not evaluate the impact of job demands on WD. Moreover, we could not examine change in the professional level i.e. downgrading to another job due to SSc in the current study. We did not use a validated psychometric instrument to assess depression in the GENISOS cohort. However, other psychometric instruments for assessment of mental health such as SF-36 MCS were utilized in the current study.
In conclusion, work disability is a prominent problem in patients with SSc. More than 40% of patients were already work disabled at early stages of the disease. After 4.4 years, more than one forth of those working at enrollment eventually became work disabled. Work disability is a function of demographic background, clinical and psychosocial factors, cross-sectionally and longitudinally. These findings underscore the need for a multi-disciplinary approach to treatment of SSc patients.