Cardiopulmonary fitness is related to disease severity in multiple sclerosis

Background: In persons with MS (pwMS), a lower cardiopulmonary fitness has been associated with a higher risk for secondary disorders, decreased functional capacity, symptom worsening and reduced health-related quality of life.

Objective: To investigate the association between disease severity and cardiopulmonary fitness.

Methods: Data from cardiopulmonary exercise tests, previously conducted in three different countries, were pooled. The association between disease severity (Expanded Disability Status Scale (EDSS)) and cardiopulmonary fitness (peak oxygen uptake (VO2peak)) was adjusted for age, sex and the country of origin.

Results: The combined sample comprised 116 ambulant pwMS having a mean (± SD) EDSS score of 2.7 ± 1.3. There was a significant correlation (r = -0.418, p < .01) between VO2peak and EDSS. A multiple regression model (R(2) = 0.520, p < .01) was constructed to describe VO2peak (mL∙kg(-1)∙min(-1)); VO2peak = 36.622 - 5.433 (Sex (1=men)) - 0.124 (Age) - 2.082 (EDSS) + 2.737 (Belgium) + 8.674 (Denmark).

Conclusion: There was a significant association between disease severity and cardiopulmonary fitness. The close relation between cardiopulmonary fitness and chronic conditions associated with physical inactivity, suggest a progressive increase in risk of secondary health conditions in pwMS.