Validation of the Symptomscreen with Objective Clinical Outcome Measures

Background: People with multiple sclerosis (MS) commonly experience symptoms in multiple domains. Development of high-quality patient-reported outcomes (PROs) that accurately assess symptom severity in multiple domains rapidly and easily can aid healthcare providers in assessing and monitoring these symptoms, and may support remote monitoring of the disease. The recently developed “SymptoMScreen” PRO measure correlates strongly with other common PROs in MS including Performance Scales. However, the association between SymptoMScreen and objective or clinician-assessed outcomes is unknown.

Objectives: To validate SymptoMScreen against objective or clinician-assessed measures of overall disability, ambulation, dexterity, and visual function.

Methods: We conducted a validation study of the “SymptoMScreen” in a population of people with MS at a large tertiary care center. SymptoMScreen uses 7-point Likert scales to measure symptom severity in 12 domains: mobility, dexterity, body pain, sensation, bladder function, fatigue, vision, dizziness, cognition, depression, and anxiety. Participants completed a timed 25-foot walk, 9-hole peg test and low-contrast letter acuity assessment at clinic visits and were asked to complete an online version of the SymptoMScreen through an online survey following clinic visits. We assessed criterion and construct validity by calculating Spearman rank correlations between SymptoMScreen subscales and the respective clinical outcome measure. 

Results: To date, 126 people with MS (average age [standard deviation]: 48.7 [11.5] years; 78% female, mean disease duration: 16.0 [10.8] years) have completed SymptoMScreen and the objective clinical measures. SymptoMScreen ambulation scores correlated strongly with timed 25-foot walk scores (r=0.72; P<0.001). More modest correlations were observed for SymptoMScreen dexterity subscales and 9-hole peg-test scores (r=0.36; P=0.02) and for visual subscales with low-contrast letter acuity (r=0.29; P=0.04). Analyses assessing the association between the composite SymptoMScreen and global disability as measured using the Expanded Disability Status Scale are ongoing.

Conclusions: These preliminary analyses suggest the SymptoMScreen to be a practical PRO whose subscales may provide a valid assessment of corresponding objective clinical measures.