The usefulness of evaluative outcome measures in patients with multiple sclerosis

Abstract

To select the most useful evaluative outcome measures for early multiple sclerosis, we included 156 recently diagnosed patients in a 3-year follow-up study, and assessed them on 23 outcome measures in the domains of disease-specific outcomes, physical functioning, mental health, social functioning and general health. A global rating scale (GRS) and the Expanded Disability Status Scale (EDSS) were used as external criteria to determine the minimally important change (MIC) for each outcome measure. Subsequently, we determined whether the outcome measures could detect their MIC reliably. From these, per domain the outcome measure that was found to be most sensitive to changes (responsive) was identified. At group level, 11 outcomes of the domains of physical functioning, mental health, social functioning and general health could reliably detect the MIC. Of these 11, the most responsive measures per domain were the Medical Outcome Study 36 Short Form sub-scale physical functioning (SF36pf), the Disability and Impact Profile (DIP) sub-scale psychological, the Rehabilitation Activities Profile sub-scale occupation (RAPocc) and the SF36 sub-scale health, respectively. Overall, the most responsive measures were the SF36pf and the RAPocc. In individual patients, none of the measures could reliably detect the MIC. In sum, in the early stages of multiple sclerosis the most useful evaluative outcome measures for research are the SF36pf (physical functioning) and the RAPocc (social functioning).

A novel approach to estimate the minimally important difference for the fatigue impact scale in multiple sclerosis patients

“…The high degree of average impairment in HRQOL reflected in the SF-36 scores was consistent with the observation that roughly 50% of the sample had an EDSS score of 6 or higher. Furthermore, in our sample, patterns of compromised SF-36 scores in HRQOL domains and increasing neurologic disability appeared consistent with previous findings [49,57,58].…”

“…The clinician's perspective was captured by the EDSS that was used as the clinical anchor in the study. Despite the known shortcomings of the EDSS scale [48], it remains an important clinical indicator for MS disease severity [20,49]. In our sample, we found that EDSS scores had an approximately bimodal distribution, with only 21 (11.4%) patients receiving scores between 3.5 and 5.5.…”

Assessing walking disability in multiple sclerosis

“…35 Although one study found a MICD for deterioration (MICD det ) of -0.08 and -0.14 m/sec at normal speed and -0.19 and -0.11 m/sec at fastest speed on the 10MTW based on clinician and patient perception of change, respectively, 49 other studies were unable to define a reliable MICD det for this measure. 39,50 Another study found a 1 m/sec change in the 10MTW had good sensitivity and specificity for predicting limitations in activities and participation in ADLs. 37 The smallest reliable change in the 30MTW at forced walking speed was an increase of 40% or a decrease of 29% in time based on day-to-day variability.…”

Linking measurement error to minimal important change of patient-reported outcomes

“…Figure 1a and b show that an observed change can only be considered an important change if it is at least four times larger than the SEM and larger than the MIC. See also the work of de Groot et al for an example in patients with multiple sclerosis [16].…”