The MSOAC approach to developing performance outcomes to measure and monitor multiple sclerosis disability.

BACKGROUND: The Multiple Sclerosis Outcome Assessments Consortium (MSOAC) was formed by the National MS Society to develop improved measures of multiple sclerosis (MS)-related disability. OBJECTIVES: (1) To assess the current literature and available data on functional performance outcome measures (PerfOs) and (2) to determine suitability of using PerfOs to quantify MS disability in MS clinical trials. METHODS: (1) Identify disability dimensions common in MS; (2) conduct a comprehensive literature review of measures for those dimensions; (3) develop an MS Clinical Data Interchange Standards Consortium (CDISC) data standard; (4) create a database of standardized, pooled clinical trial data; (5) analyze the pooled data to assess psychometric properties of candidate measures; and (6) work with regulatory agencies to use the measures as primary or secondary outcomes in MS clinical trials. CONCLUSION: Considerable data exist supporting measures of the functional domains ambulation, manual dexterity, vision, and cognition. A CDISC standard for MS ( http://www.cdisc.org/therapeutic#MS ) was published, allowing pooling of clinical trial data. MSOAC member organizations contributed clinical data from 16 trials, including 14,370 subjects. Data from placebo-arm subjects are available to qualified researchers. This integrated, standardized dataset is being analyzed to support qualification of disability endpoints by regulatory agencies.

Estimating a minimal clinically important difference for the EuroQol 5-Dimension health status index in persons with multiple sclerosis.

BACKGROUND: Limited data define what constitutes a minimal clinically important difference (MCID) on the EuroQol 5-Dimension (EQ-5D) health status index in persons with multiple sclerosis (PwMS). We sought to estimate the MCID for the EQ-5D health index in North American PwMS. METHODS: PwMS completing the Patient Determined Disease Steps (PDDS) scale, 12-Item Multiple Sclerosis Walking Scale (MSWS-12) and EQ-5D as part of the North American Research Committee on Multiple Sclerosis (NARCOMS) registry's spring 2011 update and supplemental survey were included in this retrospective, cross-sectional study. Distribution-based (standard error of measurement [SEM], 0.50 standard deviation [SD] and 0.33 SD unit) approaches were used to estimate a range of MCIDs for the EQ-5D based upon disease severity groups determined by the PDDS and MSWS-12 tertiles. RESULTS: A total of 3,044 participants were included. Moderately strong correlations between the EQ-5D and the PDDS and MSWS-12 were observed (Spearman's r = -0.56 and -0.59, respectively, p < 0.0001 for both). MCID estimates based on PDDS score categories ranged from 0.065-0.158 (SEMs), 0.059-0.142 (0.50 SDs) and 0.039-0.095 (0.33 SDs). MCID estimates as measured by MSWS-12 tertile categories ranged from 0.068-0.098 (SEMs), 0.061-0.088 (0.50 SDs), and 0.041-0.059 (0.33 SDs). Across both the PDDS and tertiles of MSWS-12, MCID estimates tended to be larger as disease severity worsened. Mean weighted MCID estimates ranged from 0.05-0.084 for both the PDDS and MSWS-12 tertiles. CONCLUSION: MCID estimates for the EQ-5D in PwMS were within the range of estimates seen for other disease states and appeared to be larger in those reporting more severe disease.

Estimation of the effect of dalfampridine-ER on health utility by mapping the MSWS-12 to the EQ-5D in multiple sclerosis patients.

BACKGROUND: Trials have not assessed the effect of dalfampridine-extended release (dalfampridine-ER) on health utility. We sought to evaluate the effect of dalfampridine-ER tablets (prolonged-release fampridine in Europe) on health utility in patients with multiple sclerosis (MS) by mapping subjects' individual item scores from the 12-Item Multiple Sclerosis Walking Scale (MSWS-12) onto the Euroqol 5-Dimension (EQ-5D) health utility index. METHODS: Data from study MS-F203, a randomized trial of dalfampridine-ER tablets, 10 mg twice daily, in patients with MS, were used to calculate the health utility scores with two MSWS-12 to EQ-5D mapping equations (one derived in a North American [NA] registry, the other a United Kingdom [UK] registry). MS-F203 participants were categorized as dalfampridine-ER 20%-responders (achieving ≥20% improvement on the Timed 25-Foot Walk), dalfampridine-ER 20%-nonresponders (<20% improvement), or placebo patients. Mean change in health utility scores from baseline to each double-blind treatment evaluation (visits 3-6 occurring at post-randomization weeks 2, 6, 10, and 14) and each off-drug follow-up evaluation (visits 7-8 occurring at weeks 16 and 18) were calculated and reported as effect sizes (ESs). RESULTS: Using the NA-derived equation, dalfampridine-ER 20%-responders demonstrated improvement in health utility vs. placebo; starting at week 6 (mean difference in ES = 0.44, p = 0.002) and maintained at weeks 10 (ES = 0.41, p = 0.01) and 14 (ES = 0.71, p < 0.001). These improvements were no longer evident after dalfampridine-ER was discontinued (p > 0.05 at weeks 16 and 18). Dalfampridine-ER 20%-nonresponders did not show improvement vs. placebo at any visit (p > 0.05 for all). When using the UK-derived equation, improvement was seen in dalfampridine-ER 20%-responders vs. placebo at weeks 2, 6, 10, and 14 (ESs = 0.49, 0.55, 0.59, and 0.99; p < 0.03 for all), but not when dalfampridine-ER was discontinued (weeks 16 and 18; p > 0.05 for both). Dalfampridine-ER 20%-nonresponders showed no improvement at any visit (p > 0.05 for all). CONCLUSION: Regardless of the equation used, dalfampridine-ER response was associated with an improvement in health utility.

Mapping of Multiple Sclerosis Walking Scale (MSWS-12) to five-dimension EuroQol (EQ-5D) health outcomes: an independent validation in a randomized control cohort.

BACKGROUND: Mapping of patient-reported outcomes to the five-dimension EuroQol (EQ-5D) health index is increasingly being used for understanding the relationship of outcomes to health states and for predicting utilities that have application in economic evaluations. The 12-item Multiple Sclerosis Walking Scale (MSWS-12) is a patient-reported outcome that assesses the impact of walking impairment in people with MS. An equation for mapping the MSWS-12 to the EQ-5D was previously developed and validated using a North American Research Committee on MS (NARCOMS) registry cohort. MATERIALS AND METHODS: This analysis retested the validity of the equation mapping the MSWS-12 to the three-level EQ-5D (EQ-5D-3L) by using an independent cohort of patients with MS enrolled in a randomized controlled trial. Mapping was evaluated at two separate time points (baseline and week 4) during the clinical trial. The mapping equation's performance was subsequently assessed with mean absolute error (MAE) and root-mean-square error (RMSE) by comparing equation-based estimates to values elicited in the trial using the actual EQ-5D-3L questionnaire. RESULTS: The mapping equation predicted EQ-5D-3L values in this external cohort with reasonable precision at both time points (MAE 0.116 and RMSE 0.155 at baseline; MAE 0.105 and RMSE 0.138 at week 4), and was similar to that reported in the original NARCOMS cohort (MAE 0.109 and RMSE 0.145). Also as observed in the original NARCOMS cohort, the mapping equation performed best in patients with EQ-5D-3L values between 0.50 and 0.75, and poorly in patients with values <0.50. CONCLUSION: The mapping equation performed similarly in this external cohort as in the original derivation cohort, including a poorer performance in MS patients with more severe health-state severity.

Prescriber utilization of dalfampridine extended release tablets in multiple sclerosis: a retrospective pharmacy and medical claims analysis.

PURPOSE: This study aimed to characterize the prescribing of dalfampridine extended release (D-ER) 10 mg tablet treatment in people with multiple sclerosis (MS). METHODS: A retrospective cohort study was performed using Medco pharmacy and medical claims. Medical claims were used to identify MS patients with more than one prescription for D-ER with 1 year of prior continuous enrollment (n=704). These patients were matched 2:1 on age, sex, and health insurance source with a comparison group of MS patients who were treatment naïve for D-ER (n=1,403). Categorical data were analyzed by χ (2) test; ordinal data by Wilcoxon rank sum test; and continuous data by Student's t-test. RESULTS: Most patients were women aged 45-64 years. In the year preceding D-ER initiation, the prevalence of seizure and renal impairment was numerically lower in the D-ER cohort relative to those who were D-ER naïve (seizure: 3.1% versus 4.7%, respectively; renal impairment: 4.3% versus 5.1%, respectively); however, prescriptions for antiepileptic drugs in the two cohorts were comparable. In the year preceding treatment initiation, 62% of the D-ER cohort was prescribed MS-specific disease-modifying therapies relative to 45% who were D-ER naïve. CONCLUSION: Seizure and renal impairment rates among D-ER-naïve patients were consistent with published literature, yet rates among those prescribed D-ER during the year preceding treatment initiation were slightly lower than rates among D-ER-naïve patients. Given that D-ER is contraindicated in patients with history of seizure or moderate or severe renal impairment, lower rates may indicate that risk-minimization strategies contributed to the lower prevalence.

Walking speed and health-related quality of life in multiple sclerosis.

OBJECTIVE: The aim of this study was to evaluate the association between slower walking and health-related quality of life (HRQoL) in multiple sclerosis (MS) patients. METHODS: We used North American Research Committee on Multiple Sclerosis data to conduct a study of participants completing both the regular semiannual and supplemental spring 2010 surveys. Question 10 of the 12-item Multiple Sclerosis Walking Scale ("How much has your MS slowed down your walking?") was used to assess patient-perceived impact of walking speed on HRQoL.HRQoL assessments included the Short Form-12 (SF-12),EuroQoL-5 Dimension (EQ-5D), Short Form-6 Dimension(SF-6D), and a visual analog scale (VAS). RESULTS: A total of 3,670 registrants completed both surveys and were included. Unadjusted analyses showed that compared with those classifying the impact of MS on walking speed as "not at all" (n = 661), participants stating MS impacted their walking speed "a little" (n = 722), "moderately" (n = 486), "quite a bit" (n = 714), and "extremely" (n = 1,087) reported poorerSF-12 physical component scale (PCS) (r = -0.69,p\0.001), mental component scale (MCS) (r = -0.16,p\0.001), and health status index scores (r = -0.50 to-0.51 for the EQ-VAS, EQ-5D and SF-6D, p\0.001 for all). After adjustment for demographics and additional MS related disability and symptoms, the impact of walking speed remained significant, although less profound for the PCS (reductions of 3.59 ­12.31 across walking speed classifications)and index scores (reductions ranging from 1.98 to 14.06, 0.04 to 0.13, and 0.02 to 0.07 for the EQ-VAS,EQ-5D, and SF-6D). Reduction in walking speed was no longer associated with a worse MCS (p[0.05 all classifications of walking speed). CONCLUSION: Incremental decrements in HRQoL were observed as patients perceived greater levels of reduction in their walking speed.

Mobility, walking and physical activity in persons with multiple sclerosis.

OBJECTIVE: The effect of differing levels of mobility and walking disability on level of physical activity (PA) performed in persons with multiple sclerosis (PwMS) is unknown. We aimed to quantify the association between mobility and walking impairment and PA levels in PwMS. METHODS: We assessed mobility and walking impairment in >3000 North American Research Committee on Multiple Sclerosis registrants using the Patient Determined Disease Steps scale (score of 0-2 = no, 3-6 = moderate, ≥7 = severe impairment) and 12-Item Multiple Sclerosis Walking Scale (MSWS-12) score (divided into quartiles, score of 0-25 = least walking impairment, 76-100 = most). Level of PA performance (metabolic equivalent [MET] minutes/week) was estimated using the Godin Leisure-Time Exercise Questionnaire. Multivariable regression and general linear models were used to assess the impact of walking and mobility impairment on PA levels. RESULTS: Moderate and severe mobility impairment was associated with performance of 183 and 319 fewer MET minutes/week and a 65% and 90% reduced odds of performing ≥500 MET minutes/week of PA compared to no impairment (mean ± SD: 447 ± 413 MET minutes/week) (p < 0.05 for all). Compared to the first quartile of MSWS-12 score (mean ± SD: 475 ± 401), the second, third and fourth quartiles were associated with performance of 127, 216 and 268 fewer MET minutes/week and 51%, 71% and 77% reduced odds of achieving ≥ 500 MET minutes/week of PA (p < 0.05 for each). Limitations of our study include possible recall bias, use of a patient-reported rather than objective outcome and assumptions made when calculating MET minutes. CONCLUSION: Mobility and walking impairment are associated with less physical activity in PwMS.

Impact of mobility impairment on indirect costs and health-related quality of life in multiple sclerosis.

This study was conducted to estimate the indirect costs and health-related quality of life (HRQoL) (utilities) of multiple sclerosis (MS) patients in the United States (US), and to determine the impact of worsening mobility on these parameters. In collaboration with the North American Research Committee on Multiple Sclerosis (NARCOMS) registry we conducted a cross-sectional study of participants who completed the biannual update and supplemental spring 2010 survey. Demographic, employment status, income, mobility impairment, and health utility data were collected from a sample of registry participants who met the study criteria and agreed to participate in the supplemental Mobility Study. Mean annual indirect costs per participant in 2011US$ and mean utilities for the population and for cohorts reporting different levels of mobility impairment were estimated. Analyses included 3,484 to 3,611 participants, based on survey completeness. Thirty-seven percent of registrants were not working or attending school and 46.7% of these reported retiring early. Indirect costs per participant per year, not including informal caregiver cost, were estimated at $30,601±31,184. The largest relative increase in indirect costs occurred at earlier mobility impairment stages, regardless of the measure used. Participants' mean utility score (0.73±0.18) was lower than that of a similarly aged sample from the general US population (0.87). As with indirect costs, larger decrements in utility were seen at earlier mobility impairment stages. These results suggest that mobility impairment may contribute to increases in indirect costs and declines in HRQoL in MS patients.

Mapping the 12-item multiple sclerosis walking scale to the EuroQol 5-dimension index measure in North American multiple sclerosis patients.

OBJECTIVE: To map the 12-item Multiple Sclerosis Walking Scale (MSWS-12) onto the EuroQol 5-dimension (EQ-5D) health-utility index in multiple sclerosis (MS) patients participating in the North American Research Committee on Multiple Sclerosis (NARCOMS) registry. DESIGN: Cross-sectional MSWS-12 to EQ-5D cross-walking analysis. SETTING: NARCOMS registry spring 2010 biannual update and supplemental survey. PARTICIPANTS: North American patients completing both the MSWS-12 and the EQ-5D randomly split into derivation and validation cohorts. OUTCOME MEASURES: Ordinary least squares regression was performed within the derivation cohort, with participants' EQ-5D as the dependent variable. Results of the MSWS-12 were input as independent variable(s) into six regression models. Model goodness-of-fit was subsequently assessed in the validation cohort using the mean absolute error (MAE), root mean square error (RMSE) and the adjusted R(2). The best performing model was refined in the entire cohort and utilised for additional analyses. RESULTS: A total of 3505 NARCOMS participants were included. Their mean±SD EQ-5D and MSWS-12 scores were 0.74±0.18 and 50.8±33.5, respectively, and these assessments were found to be moderately correlated (r=-0.553, p<0.001). The model using all individual MSWS-12 item scores as independent variables was found to have the best fit (MAE=0.109±0.096, RMSE=0.145, adjusted R(2)=0.329). The percentage of EQ-5D estimates within 0.05 and 0.10 of the actual value were 30% and 61%, respectively. This mapping equation was more precise in patients with moderate mobility impairment (MAE=0.087±0.061 at patient-determined disease step (PDDS) of 3-6) and less precise in patients with no (MAE=0.141±0.128 at PDDS of 0-2) or severe mobility impairment (MAE=0.121±0.049 at PDDS ≥7). CONCLUSIONS: The EQ-5D scores can be predicted using the MSWS-12 item scores with reasonable precision in North American patients with MS. Prediction estimates were more precise in patients with moderate mobility impairment.