Exploratory Factor Analysis of a Patient-Reported Outcome Measure in a Multiple Sclerosis Population Cohort at a Large Academic Center

Objective: To determine the discriminant validity of the Neuro-QoL Short Form scales in a real world multiple sclerosis clinic population Background: Measures of patient-reported outcomes (PROs) have been shown to be effective for tracking treatment outcomes in multiple sclerosis (MS). However, collecting PROS during clinical standard of care can be time-consuming. Factor analysis allows for the reduction of dimensionality in questionnaires with numerous items and elucidates the items accounting for the most variance within a dimension. Design/Methods: The Quality of Life in Neurological Disorders (Neuro-QoL) Measures is a validated series of self-report questionnaires for assessing physical function and symptoms, emotional and cognitive health, and social abilities in clinical populations. A cohort of 902 patients with MS completed the Neuro-QoL. Principal axis factoring (PAF) with Quartimax rotation was performed. Results: Sample demographics include mean age=48.6±2.3, 75% female, mean disease duration= 11±8.2 years, and 75% Caucasian. Results from the PAF were consistent with the Neuro-QoL’s original reported dimensionality in the number of factors, presenting 12 domains (only 12/13 were examined; stigma was not assessed). However, not all original items sufficiently loaded onto factors. For example, only 3 of 8 items loaded for the Sleep Disturbance scale, with values ranging from 0.42 to 0.55 and a total Eigenvalue of 1.33. Only 3 of 5 Communication items loaded, with values ranging from 0.49 to 0.54 and a total Eigenvalue of 1.15. Executive Function as a factor separate from General Cognitive Concerns was not supported. Cognition, Lower and Upper Extremity Function, and Positive Affect were the strongest factors, accounting for 58% of the variance for all measure items. Conclusions: These findings support the utility of the Neuro-QoL in evaluating patient-reported outcomes in multiple sclerosis. However, not all original measure items accounted for sufficient variance in the factor analysis. Critical items for each factor are discussed. Disclosure: Dr. Medina has nothing to disclose. Dr. Valdez has nothing to disclose. Dr. Alvarez has received personal compensation from Teva Neuroscience, Biogen, Genzyme, Genentech, and Novartis. Dr. Alvarez has received research support from Biogen, Teva, and Novartis. Dr. Nair has received personal compensation for activities with Astellas. Dr. Nair has received research support from Novartis, Biogen, Gilead Sciences, and Genentech.