Multiple sclerosis (MS) is a chronic, progressive autoimmune disease of the central nervous system. Fatigue, disability, and depression are some of the clinical symptoms of MS that can be debilitating and have a major impact on quality of life (QOL).
To conduct a systematic review of evidence related to the relationship of fatigue, disability, and depression with QOL in people with MS (pwMS) over time.
Medline, EMBASE, PsycINFO, EBMR, and CINHAL were searched for articles published from database inception up to 23 March 2020. The search was restricted to peer-reviewed English-language articles that assessed the impact of at least one of the three symptoms on QOL in pwMS, using validated measurement tools and longitudinal study designs. Two independent reviewers independently identified studies, extracted the data, and rated study quality using Covidence and the ROBINS-E tool. Final studies included were agreed by consensus.
Of 1,880 studies assessed, 12 studies met the inclusion criteria; these were analysed using a descriptive approach due to large heterogeneity in exposure and outcome measures. Only two studies were identified as low risk of bias, while the remaining studies were of serious and moderate risk of bias. Fatigue at baseline was found to have consistent negative associations with QOL, particularly physical QOL. The associations of disability at baseline were most apparent with physical QOL, specifically physical functioning, role, and vitality subdomains. Depression at baseline was found to be predictive of both physical and mental health QOL.
Baseline fatigue, disability, and depression have an overall negative effect on QOL; each symptom affects different subdomains and composites of QOL over time. These symptoms should be carefully screened at initial stages to maintain QOL in pwMS. Future studies with larger sample sizes and longer follow-up periods are needed for a more comprehensive review. Additional research should also consider whether the associations differ across sex, age group, and MS type.