Working ability in individuals with different disease courses of multiple sclerosis: Factors beyond physical impairment.

BACKGROUND

Experiencing a decrease in working ability or even becoming unemployed is common in patients with multiple sclerosis (MS) and has a detrimental impact on the individual's quality of life, self-esteem, and on society's economic burden. Physical disability is still considered the most important predictor for patients' inability to work. This study aims to confirm and extend findings from prior studies indicating the additional importance of other demographical and clinical information accessible within a routine patient evaluation, placing particular emphasis on the inclusion of cognitive and neuropsychiatric measures, as well as on potential disease course differences.

METHODS

159 MS patients (84 with a relapsing disease course (RMS); 75 with a progressive disease course (PMS)) were examined with the Brief International Cognitive Assessment for MS (BICAMS) battery, mood and fatigue questionnaires, and screened for subjectively experienced cognitive problems as well as for various person- and disease-related information (age, sex, education, age at diagnosis, disease duration, immunotherapy, number and nature of comorbidities, smoking and alcohol intake, sleep disturbances). These measures, along with Expanded Disability Status Scale (EDSS) scores were compared between unemployed, part- and full-time working patients. Significant variables were further entered into hierarchical regression models predicting employment status (employed vs. unemployed) as well as weekly hours at work in each disease subtype, respectively.

RESULTS

In patients with RMS, unemployed patients had higher EDSS scores, reported a higher number of comorbidities, more frequent past depressive episodes, a higher level of fatigue, and performed worse on the Symbol-Digit Modalities Test (SDMT) and the Brief Visuospatial Memory Test revised (BVMT-R). Besides EDSS, unemployment was predicted by SDMT, while weekly hours at work were further determined by the number of comorbidities, BVMT-R, and disease duration. In patients with PMS, unemployed patients also had higher EDSS scores, were younger at diagnosis, and showed a decreased performance in SDMT and the Rey Verbal Learning and Memory Test German version (Verbaler Lern- und Merkfaehigkeitstest; VLMT). Employment status as well as weekly working hours were both predicted by VLMT, educational level, and disease duration beyond EDSS in patients with PMS, while depressive episodes additionally impacted on employment status.

CONCLUSIONS

Objectively assessed cognitive functions, neuropsychiatric symptoms (i.e. a history of depressive episodes, fatigue) as well as some specific clinical data (disease duration, comorbidities) add substantial value in the evaluation of working ability beyond physical disability. Since unemployment is associated with different major factors among disease courses, more comprehensive and customized assessments are needed to refine characterization of individual work ability and to adjust interventional strategies targeting employment maintenance.