Employment in multiple sclerosis: Use of survival analyses to examine loss of employment in the NARCOMS sample

Individuals with multiple sclerosis (MS) have been shown to have high rates of unemployment, especially as their disease progresses. This loss of employment has significant personal and economic consequences for these individuals. We used survival analysis to examine predictors of loss of employment events in the NARCOMS registry, a large national registry of individuals with MS.

The NARCOMS dataset contained all available semi-annual survey data from 2004-2008 along with original enrollment survey data for individuals in the 2004-2008 dataset. Individuals were considered employed if they answered yes to the question, “Are you currently employed.” 2,782 individuals had complete data and had at least one survey after an employed visit. The average time from first employed visit was 3.7 years. Variables considered in the model included age, sex, education, duration of MS, mobility, SF12 mental, SF12 physical, fatigue, cognition, pain, missed work, and bladder and bowel issues. Baseline and time dependant (TD) variables were both considered.

The results of the analysis found that higher age, longer duration of disease, lower SF12 physical (TD), lower SF12 mental (TD), more cognitive difficulties (TD), worse mobility (TD), and worse fatigue (TD) were all significant predictors of loss of employment. In the final model, the proportional hazards assumption and model fit were tenable.

Further research with finer grained analysis may allow identification of individual risk factors for unemployment amenable to intervention.