Cognitive function predicts work disability among multiple sclerosis patients

In multiple sclerosis various aspects of cognitive function can be detrimentally affected. More than that, patients′ employment and social functioning is likely to be impacted. To determine whether work disability among multiple sclerosis patients could be predicted by the symbol digit modalities test. A register-based cohort study was conducted. Individual data on work disability, operationalised as annual net days of sickness absence and/or disability pension were retrieved at baseline, when the symbol digit modalities test was performed, after one-year and 3-year follow-up for 903 multiple sclerosis patients. The incidence rate ratios for work disability were calculated with general estimating equations using a negative binomial distribution and were adjusted for gender, age, educational level, family composition, type of living area and physical disability. After one year of follow-up, the patients in the lowest symbol digit modalities test quartile were estimated to have a 73% higher rate of work disability when compared to the patients in the highest symbol digit modalities test quartile (incidence rate ratio 1.73, 95% confidence interval 1.42？2.10). This estimate after 3-year follow-up was similar (incidence rate ratio 1.68, 95% confidence interval 1.40？2.02). Cognitive function is to a high extent associated with multiple sclerosis patients’ future work disability, even after adjusting for other factors