Open Access
Research
Mapping the 12-item multiple sclerosis walking scale to the EuroQol 5-dimension index measure in North American multiple sclerosis patients Matthew F Sidovar,1 Brendan L Limone,2,3 Soyon Lee,2,3 Craig I Coleman2,3
To cite: Sidovar MF, Limone BL, Lee S, et al. Mapping the 12-item multiple sclerosis walking scale to the EuroQol 5-dimension index measure in North American multiple sclerosis patients. BMJ Open 2013;3:e002798. doi:10.1136/bmjopen-2013002798 ▸ Prepublication history and additional material for this paper are available online. To view these files please visit the journal online (http://dx.doi.org/10.1136/ bmjopen-2013-002798). Received 26 February 2013 Revised 9 April 2013 Accepted 23 April 2013
This final article is available for use under the terms of the Creative Commons Attribution Non-Commercial 2.0 Licence; see http://bmjopen.bmj.com
1
Medical Affairs, Acorda Therapeutics, Ardsley, New York, USA 2 Evidence Based Research Center, Hartford Hospital, Hartford, Connecticut, USA 3 Department of Pharmacy Practice, School of Pharmacy, University of Connecticut, Storrs, Connecticut, USA Correspondence to Dr Craig I Coleman;
[email protected]
ABSTRACT Objective: To map the 12-item Multiple Sclerosis Walking Scale (MSWS-12) onto the EuroQol 5dimension (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 R2. 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
