Impact of comorbidity on fatigue management intervention outcomes among people with multiple sclerosis: an exploratory investigation.

This exploratory secondary analysis examined whether the presence of six chronic health conditions moderated the effectiveness of a teleconference-delivered fatigue self-management education program for people with multiple sclerosis (MS). The longitudinal data used were from a randomized controlled trial involving 181 community-dwelling adults with MS. The primary outcome was fatigue impact, as measured by the Fatigue Impact Scale (FIS). Mixed-effects analysis of variance (ANOVA) models were used to determine the best-fitting model. Just under 65% (n = 112) of participants had at least one comorbid condition. Only diabetes and arthritis moderated all three FIS subscales over time. People with diabetes were slower to show improvement after intervention than people without diabetes. People with arthritis made much more dramatic initial gains compared with people without arthritis but had difficulty maintaining those gains over time. The results point to the need for greater attention to the impact of comorbidities on rehabilitation interventions. These exploratory findings suggest that fatigue self-management education protocols may need to be customized to people who are trying to incorporate MS fatigue self-management behaviors while simultaneously managing diabetes or arthritis.