Disease steps in multiple sclerosis: a longitudinal study comparing Disease Steps and EDSS to evaluate disease progression

Abstract

Clinical assessment of outcome in multiple sclerosis (MS) patients is problematic since the disease can affect different aspects of the central nervous system and follow a variable course. Recently, we developed Disease Steps, a simple approach for evaluating disease progression. Previously, we found that Disease Steps was easy to use, had uniformly distributed scores and low inter-rater variability. Our current objective was to test the long-term use of Disease Steps together with the most widely utilized clinical outcome measure in MS, the Expanded Disability Status Scale (EDSS) in assessing clinical progression. Over 4 years, 804 patients were classified using both EDSS and Disease Steps. Each patient was assessed at least twice. Follow-up results included annual status and time-to-event analysis examining median staying times within a level of Disease Steps or EDSS. We found that the two scales behaved similarly and correlated strongly with each other. For both Disease Steps and EDSS, patients with milder levels of disability and relapsing-remitting disease demonstrated a higher likelihood of changing scores over time and shorter median staying times compared to more disabled, chronic progressive patients. These findings have important implications for patient selection in clinical trials and for the design of future measurements of clinical outcome in MS. Furthermore, Disease Steps may serve as a simple, practical tool for the nonspecialty neurologist to follow patients over time and serve as a guide in therapeutic decision making. Our findings further document the general progressive nature of MS when a large cohort is followed in an MS specialty clinic over time.

VHA Multiple Sclerosis Surveillance Registry and its similarities to other contemporary multiple sclerosis cohorts

“…§ § Closest approximation with Performance Scale was Cognitive Disability domain. ¶ ¶ Patient Determined Disease Steps (PDDS) [19]. MSSR = MS Surveillance Registry, SD = standard deviation, w/o = without.…”

“…Disability was assessed using the Patient Determined Disease Steps (PDDS) [19] across cohorts except for the NYMSC, which did not report disability. Overall, patient-reported disability levels were similar across cohorts, although the Veteran groups (MSSR and Veteran NARCOMS) tended have a smaller proportion reporting "no or mild" disability and a slightly greater proportion that required ambulatory assistance than non-Veteran NARCOMS and SLIFKA.…”

Prediction of oxygen uptake during walking in ambulatory persons with multiple sclerosis

“…The total MSWS-12 score is between 0 and 100 and is calculated by first adding the individual item scores, subtracting 12 (the minimum possible score), dividing by 48 (the maximal score), and then multiplying the result by 100. The PDDS is an inexpensive surrogate for the Expanded Disability Status Scale for evaluating disability status and disease progression in persons with MS and has strong validity evidence [19][20]25]. The PDDS consists of a single item for assessing self-reported disability status on an ordinal scale, ranging from 0 (normal) through 8 (bedridden).…”

“…The MSWS-12 includes 12 patient-rated items that assess the multifactorial effect of MS on walking [18]. The PDDS consists of a single item for measuring self-reported functional impairment, with particular focus on ambulation [19][20]. MSWS-12 and PDDS scores have been positively associated with the energetic cost of walking in persons with MS [21][22].…”

Core muscle characteristics during walking of patients with multiple sclerosis

“…Patients with MS were assessed for disability levels using the Patient Determined Disease Steps (PDDS), which has been validated and shows a high correlation to the Expanded Disability Status Scale [19][20][21][22][23]. Measurements of height, weight, leg spasticity (using the MASS), comfortable walking speed, and muscle strength preceded 15 min of treadmill walking.…”