Objective and subjective measures of dalfampridine efficacy in clinical practice

The subjective minimal important change for the Six Spot Step Test in people with multiple sclerosis - The Danish MS Hospitals Rehabilitation study

INTRODUCTION

The Six Spot Step Test has shown good psychometric properties in terms of validity and reliability in people with multiple sclerosis. Yet, the responsiveness and minimal important change are unknown. The objective was to investigate the responsiveness of the Six Spot Step Test against the perceived change of walking limitations and establish estimates for the minimal important change in people with multiple sclerosis.

METHODS

The Six Spot Step Test was performed before and after four weeks of specialised multidisciplinary inpatient rehabilitation by 142 adults with mild to severe multiple sclerosis. Responsiveness was determined based on anchor- and distribution-based methods, using the Multiple Sclerosis Walking Scale-12 as external criterion. In a supplementary analysis, the Six-Minute Walking Test was used as an external criterion.

RESULTS

The correlation between the baseline (r = 0.56, p < 0.01) and discharge (r = 0.55, p < 0.01) Multiple Sclerosis Walking Scale-12 and Six Spot Step Test scores were acceptable. Furthermore, the change scores were weakly associated (r = 0.1, p = 0.27). This trend was similar for the Six-Minute Walking Test when used as anchor. The smallest detectable change was estimated to 1.7 seconds. An improvement in the Six Spot Step Test exceeding 2.1 (95% CI - 0.9 to 5.0) sec and 4.9 (95% CI 1.2-8.6) sec may be considered clinically important on a group level based on the Multiple Sclerosis Walking Scale-12 and the Six-Minute Walking Test, respectively.

CONCLUSION

In a sample of mild to severely disabled people with multiple sclerosis, the Six Spot Step Test showed fair responsiveness against a subjective and objective criterion, indicating a minimal important change between ≥ 2.1 and ≥ 4.9 seconds, respectively. However, a weak association between the change in the Six Spot Step Test and the subjective and objective external criterion calls for cautious interpretation. Hence, the results should be further verified against a valid external criterion.

Mobile-phone-based e-diary derived patient reported outcomes: Association with clinical disease activity, psychological status and quality of life of patients with multiple sclerosis

BACKGROUND

The applicability of mobile digital technology to promote clinical care of people with multiple sclerosis (pwMS) is gaining increased interest as part of the implementation of patient-centered approaches. We aimed at assessing adherence to a smartphone-based e-diary, which was designed to collect patient-reported outcomes (PROs). Secondary objectives were to evaluate the construct and predictive validity of e-diary derived PROs and to explore the various factors that were associated with changes in PROs over time.

MATERIALS AND METHODS

In this observational cohort study patients downloaded an MS tailored e-diary into their personal smartphones. Report of PROs was enquired once monthly for a period of one year through a smartphone-based application, using previously validated tools. An e-diary derived bodily function summary score (eBF) was defined as the sum of scores depicting vision, limbs function, pain, bowl/ bladder dysfunction, pseudobulbar affect and spasticity. Multiple linear regression and analysis of covariance were used to determine the association between PROs, clinician-reported outcomes (ClinROs) of disease activity and quality of life (QoL). Regression coefficient analysis was used to compare the slope of change in eBF before and after a relapse.

RESULTS

97 pwMS downloaded the e-diary [Female: 64 (66%), EDSS 3.4±2.1]. 76 patients (78%) completed the 12-month study period. 53 patients (55%) submitted ≥75% of requested surveys. Anxiety was negatively associated with adherence to periodic PROs assessments by the e-diary. E-diary derived PROs were significantly correlated with corresponding functional system scores (0.38< r <0.8, P<0.001). eBF score significantly predicted QoL (β = -0.36, P = 0.001) while EDSS did not. Change in eBF score over time was independently associated with the occurrence of an MS relapse (F = 4.4, P = 0.04), anxiety (F = 6.4, P = 0.01) and depression (F = 5.1, P = 0.03). Individual regression slopes of eBF scores were significantly higher pre-relapse than post-relapse (3.0±3.3 vs. -0.8±2.0, P = 0.007).

CONCLUSION

Adherence of pwMS to recording in an e-diary collecting PROs was high. Changes in e-diary derived PROs over time predict clinical MS relapses on the group level and thus carry the potential of usage in clinical research as well as for improved MS care in real world setting.