Cumulative impact of comorbidity on quality of life in MS

BACKGROUND: Little is known about the impact of comorbidity on health-related quality of life (HRQOL) in multiple sclerosis (MS). We investigated the association of comorbidity and health-related HRQOL among participants in the North American Research Committee on Multiple Sclerosis (NARCOMS). MATERIALS AND METHODS: In 2006, we queried NARCOMS participants regarding physical and mental comorbidities and HRQOL, using the Short-Form 12. We summarized physical HRQOL using the aggregate Physical Component Scale (PCS-12) score and mental HRQOL using the aggregate Mental Component Scale (MCS-12) score. We assessed multivariable associations between comorbidity and HRQOL using a general linear model, adjusting for potential confounders. RESULTS: Among 8983 respondents, the mean (SD) PCS-12 was 36.9 (11.8) and MCS-12 was 45.6 (11.6). After adjustment for sociodemographic and clinical factors, participants with any physical comorbidity had a lower PCS-12 (37.2; 95% CI: 36.4-38.1) than those without any physical comorbidity (40.1; 95% CI: 39.0-41.1). As the number of physical comorbidities increased, PCS-12 scores decreased (r = -0.25; 95% CI: -0.23 to -0.27) indicating lower reported HRQOL. Participants with any mental comorbidity had a lower MCS-12 (40.7; 95% CI: 39.8-41.6) than those without any mental comorbidity (48.5; 95% CI: 47.7-49.4). CONCLUSIONS: Comorbidity is associated with reduced HRQOL in MS. Further research should evaluate whether more aggressive treatment of comorbidities improves the HRQOL of MS patients.