Hidden symptoms of multiple sclerosis increase with patient age

Background: Although many of the more obvious symptoms of multiple sclerosis (MS), such as weakness, ataxia, and bladder problems, are incorporated into the Kurtzke Expanded Disability Status Scale (EDSS), less information is available on the prevalence of "hidden" manifestations of this disease, such as fatigue, depression, pain, and anxiety. The recent completion of the NIH-funded PROMIS and Neuro-QoL initiatives allow comparison of less apparent symptoms with age-matched norms from a large, industrialized population.  The aim of the current study was to compare less apparent symptoms of MS as well as quality of life (QoL) indicators with population norms and to stratify changes in symptom burden with increasing age.

Methods: PROMIS short forms, based on US population norms, on 11 hidden symptoms (fatigue, depression, pain interference, anxiety, sleep disturbance, and wake disturbance) and quality of life indicators (cognitive concerns, executive functioning, physical function, global mental function, and social role) were completed by 1,543 individuals with MS in three cross-sectional surveys.  Scores for the overall sample were compared on Neuro-QoL cognitive function.  Results in 9 domains from age groups 18-34 (n=104), 35-44 (n=195), 45-54 (n=440), 55-64 (n=544), 65-74 (n=223) and older than 75 (n=37) were compared with PROMIS population norms.

Results: When comparing the whole sample to the US population, adults with MS reported significantly higher symptom burden on all 11 domains, (p<0.0001).  Depression showed the least difference and physical function the greatest difference. Comparisons to age group norms showed increasing symptom burden in older cohorts.  The 18-34 group reported significantly higher levels of fatigue, pain interference, sleep disturbance, and physical function than the corresponding age norm, (p<0.005).  Age groups 35-44 and 45-54 reported significantly higher burden on all domains except global mental function while age groups 55-64 and 65-74 reported higher burden on all 9 domains compared with PROMIS population norms (except age group 65-74 reported significantly less sleep disturbance), (p<0.005).

Conclusion:  Our findings indicate that most of these less-apparent symptoms increase with age. In particular, physical and mental function and satisfaction with social role decrease while fatigue increases most with age.  Older adults living with MS may require targeted health care strategies to optimize quality of life.