OBJECTIVE: To create a reference table of disability outcomes in multiple sclerosis (MS) that would enable MSers to rank their disability relative to others’ with similar disease duration and to develop a cost-effective research tool for comparing MS severity across MSer populations and time periods.
METHODS: The North American Research Committee on Multiple Sclerosis (NARCOMS) Registry collects disability data from MSers on a validated, 9-point Patient-Determined Disease Steps (PDDS) scale. The investigators’ compiled the Disability Expectancy Table, which displays cumulative frequencies of PDDS scores for each year of disease duration, from 0 to 45 years. They also tabulated disease duration-adjusted mean ranks of PDDS scores, referred to as Patient-derived MS Severity Scores (P-MSSS).
RESULTS: The cohort consisted of 27,918 NARCOMS enrollees, 72.7% of whom were female and 90.1% of whom were white. Mean age at symptom onset was 30.1 ± 10.1 years, and age at enrollment was 47.1 ± 11.0 years. The Disability Expectancy Table and P-MSSS afford a detailed overview of disability outcomes in a large MS cohort over a 45-year period. In the first year of disease, 15% of MSers reported need of ambulatory aid, and 4% needed bilateral assistance or worse; after 45 years of disease, 76% of MSers required ambulatory aid, and 52% bilateral assistance or worse. Proportion of MSers who reported minimal or no interference in daily activities (PDDS ≤ 1) declined from 63% in the first year to 8% after 45 years of disease.
CONCLUSION: The Disability Expectancy Table allows individual patients to determine how their disability ranks relative to NARCOMS enrollees with the same disease duration. P-MSSS may be used to compare disability across MSer populations and to track disease progression in MSer cohorts. P-MSSS does not require a formal neurologic examination and may therefore find wide applicability as a practical and cost-effective outcome measure in epidemiologic studies.
“The concept in this study has already been done with the EDSS and is called the MS Severity Scale (MSSS). The advantage of this scale is that it will potentially allow MSers to work-out their own level of disability using a patient-related outcome (PRO) or outcome measure (PROM) and to compare it the course of a population is similar MSers. This will tell you if you disease rapid your disability is progressing. Knowing if you have benign or malignant disease will allow you to make better informed treatment decisions; particularly in relation to more risky treatments. What do you think?”