Estimating the relative contribution of comorbidities in predicting health-related quality of life of people with multiple sclerosis.

Background: Little is known about the relative contribution of comorbidities in predicting the health-related quality of life (HRQoL) of people with Multiple Sclerosis (PwMS).
Objective: To determine the associations between the number of and individual comorbidities and HRQoL and estimate the relative contribution of different comorbidities on HRQoL.
Methods: Cross-sectional analysis of data on self-reported presence of 30 comorbidities and HRQoL from the Australian MS Longitudinal Study (AMSLS) participants (n = 902). HRQoL was measured using the Assessment of Quality of Life-8 Dimensions (AQoL-8D). Linear regression and general dominance analysis were used.
Results: Higher number of comorbidities was associated with lower HRQoL (p trend p < 0.01). Comorbidities accounted for 18.1% of the variance in HRQoL. Mental health and musculoskeletal disorders were the strongest contributors to lower HRQoL. Of individual comorbidities, systemic lupus erythematosus (SLE) [β = - 0.16 (- 0.27, - 0.05)] and depression [β = - 0.15(- 0.18, - 0.13)] were most strongly associated with overall HRQoL, depression [β = - 0.14(- 0.16, - 0.11)] and anxiety [β = - 0.10 (- 0.13, - 0.07)] with psychosocial HRQoL, and SLE [β = - 0.18 (- 0.29, - 0.07)], rheumatoid arthritis [β = - 0.11 (- 0.19, - 0.02)] and hyperthyroidism [β = - 0.11 (- 0.19, - 0.03)) with physical HRQoL.
Conclusion: Comorbidities potentially make important contributions to HRQoL in PwMS. Our findings highlight groups of and individual comorbidities that could provide the largest benefits for the HRQoL of PwMS if they were targeted for prevention, early detection, and optimal treatment.