Patient reported outcomes in NMOSD reflect a high disease burden and do not correlate with the EDSS.

BACKGROUND

The Expanded Disability Status Scale (EDSS) is routinely used to evaluate disability in Neuromyelitis Optica Spectrum Disorder (NMOSD), although it has only been validated in multiple sclerosis (MS) and may not capture important aspects of the patient experience in NMOSD.

OBJECTIVE

To evaluate the relationship between Patient-Reported Outcomes (PROs), including for pain, fatigue, anxiety, and depression, and EDSS scores in NMOSD.

METHODS

This cross-sectional study used baseline visit data from participants with aquaporin-4 antibody positive NMOSD who were enrolled in the multi-centre Canadian NMOSD cohort study CANOPTICS and had consented to the PROs substudy. Participants completed the following PROs: the short-form McGill Pain Questionnaire (sf-MPQ), Modified Fatigue Impact Scale (MFIS), Generalized Anxiety Disorder Assessment 7-item scale (GAD-7), and Beck Depression Inventory II (BDI-II). We evaluated PRO scores overall and stratified by demographic factors including sex, age, and ethnicity. We assessed the correlation among PROs and between each PRO and the EDSS. Multivariable linear regression models were used to identify the association between demographic and clinical characteristics (including EDSS) and two key symptom domains, pain and fatigue, given their high prevalence and impact in NMOSD.

RESULTS

Out of 69 included participants, 57 (82.6%) were female and median (IQR) age was 50 years (40-61). Median (IQR) scores were: sf-MPQ 7 (1-16), MFIS 39 (22-50), GAD-7 5 (2-8), BDI-II 11 (4-19), and EDSS 3.0 (1.5-4.0). Depression and fatigue (r=0.71), fatigue and pain (r=0.62), and depression and anxiety (r=0.69) were correlated, but correlations between EDSS and PROs were weak (r<0.25). No significant differences in PROs were observed by sex, age and ethnicity, although female sex was associated with a higher fatigue score in multivariable models (beta = 12.69, 95% CI 0.33-25.04).

CONCLUSIONS

There was a substantial burden of fatigue, pain, and mood disorders in this NMOSD cohort; however, these outcomes were weakly correlated with EDSS scores, suggesting that the EDSS may not capture important aspects of the patient experience in NMOSD.