Development and validation of the self-reported disability status scale (SRDSS) to estimate EDSS-categories

Marco Kaufmann; Anke Salmen; Laura Barin; Milo Alan Puhan; Pasquale Calabrese; Christian Philipp Kamm; Claudio Gobbi; Jens Kuhle; Zina-Mary Manjaly; Vladeta Ajdacic-Gross; Sandra Schafroth; Britta Bottignole; Sabin Ammann; Chiara Zecca; Marcus D'Souza; Viktor von Wyl; Swiss Multiple Sclerosis Registry (SMSR)

doi:10.1016/j.msard.2020.102148

Development and validation of the self-reported disability status scale (SRDSS) to estimate EDSS-categories

Mult Scler Relat Disord. 2020 Jul:42:102148. doi: 10.1016/j.msard.2020.102148. Epub 2020 Apr 28.

Authors

Marco Kaufmann¹, Anke Salmen², Laura Barin³, Milo Alan Puhan⁴, Pasquale Calabrese⁵, Christian Philipp Kamm⁶, Claudio Gobbi⁷, Jens Kuhle⁸, Zina-Mary Manjaly⁹, Vladeta Ajdacic-Gross¹⁰, Sandra Schafroth¹¹, Britta Bottignole¹², Sabin Ammann¹³, Chiara Zecca¹⁴, Marcus D'Souza¹⁵, Viktor von Wyl¹⁶; Swiss Multiple Sclerosis Registry (SMSR)

Affiliations

¹ Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland. Electronic address: marco.kaufmann@uzh.ch.
² Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland. Electronic address: anke.salmen@insel.ch.
³ Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; FBK-IRVAPP, Research Institute for the Evaluation of Public Policies, Bruno Kessler Foundation, Trento, Italy. Electronic address: laura.barin@gmail.com.
⁴ Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland. Electronic address: miloalan.puhan@uzh.ch.
⁵ Division of Molecular and Cognitive Neuroscience, University of Basel, Basel, Switzerland. Electronic address: pasquale.calabrese@unibas.ch.
⁶ Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland; Neurocentre, Luzerner Kantonsspital, Luzern, Switzerland. Electronic address: christian.kamm@luks.ch.
⁷ Faculty of biomedical Sciences, Università della Svizzera Italiana (USI), Lugano, Switzerland; Department of Neurology, Multiple Sclerosis Center (MSC), Neurocenter of Southern Switzerland, Lugano, Switzerland. Electronic address: Claudio.Gobbi@eoc.ch.
⁸ Neurologic Clinic and Policlinic, University Hospital and University of Basel, Departments of Medicine, Biomedicine and Clinical Research, Basel, Switzerland. Electronic address: Jens.Kuhle@usb.ch.
⁹ Department of Neurology, Schulthess Clinic, Zürich, Switzerland; Department of Health Sciences and Technology, ETH Zurich, Zürich, Switzerland. Electronic address: Zina-Mary.Manjaly@kws.ch.
¹⁰ Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland. Electronic address: vajdacic@dgsp.uzh.ch.
¹¹ Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland. Electronic address: sandra.schafroth2@uzh.ch.
¹² Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland. Electronic address: b.bottignole@neurozentrumbellevue.ch.
¹³ Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland. Electronic address: sabin.ammann@uzh.ch.
¹⁴ Faculty of biomedical Sciences, Università della Svizzera Italiana (USI), Lugano, Switzerland; Department of Neurology, Multiple Sclerosis Center (MSC), Neurocenter of Southern Switzerland, Lugano, Switzerland. Electronic address: Chiara.Zecca@eoc.ch.
¹⁵ Neurologic Clinic and Policlinic, University Hospital and University of Basel, Departments of Medicine, Biomedicine and Clinical Research, Basel, Switzerland. Electronic address: marcus.dsouza@usb.ch.
¹⁶ Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland. Electronic address: viktor.vonwyl@uzh.ch.

PMID: 32371376
DOI: 10.1016/j.msard.2020.102148

Abstract

Background: Clinician-assessed Expanded Disease Status Scale (EDSS) is gold standard in clinical investigations but normally unavailable in population-based, patient-centred MS-studies. Our objective was to develop a self-reported gait measure reflecting EDSS-categories.

Methods: We developed the self-reported disability status scale (SRDSS) with three categories (≤3.5, 4-6.5, ≥7) based on three mobility-related questions. The SRDSS was determined for 173 persons with MS and validated against clinical EDSS to calculate sensitivity and specificity.

Results: Accuracy was 88.4% (153 correctly classified) and weighted kappa 0.73 (0.62-0.84). Sensitivity/specificity-pairs were 94.5%/77.8%, 69.0%/94.7% and 100%/98.2% for SRDSS ≤3.5, 4-6.5 and ≥7, respectively.

Conclusions: Self-reported SRDSS approximates EDSS-categories well and fosters comparability between clinical and population-based studies.

Keywords: EDSS; Patient reported outcome; Proxy measure; Registries; Self-report.

Publication types

Validation Study

MeSH terms

Adult
Female
Gait* / physiology
Humans
Male
Middle Aged
Multiple Sclerosis / diagnosis*
Multiple Sclerosis / physiopathology
Prospective Studies
Psychometrics / standards*
Reproducibility of Results
Self Report / standards*
Sensitivity and Specificity
Severity of Illness Index*