title: Derivation and Validation of a Modified Short Form of the Stroke Impact Scale.
abstract: The Stroke Impact Scale (SIS) is a stroke-specific, quality of life measure recommended for research and clinical practice. Completion rates are suboptimal and could relate to test burden. We derived and validated a short form SIS (SF-SIS).
  
  
  
  We examined data from the Virtual International Stroke Trial Archive, generating derivation and validation populations. We derived an SF-SIS by selecting 1 item per domain of SIS, choosing items most highly correlated with total domain score. Our validation described agreement of SF-SIS with original SIS and the SIS-16 and correlation with Barthel Index, modified Rankin Scale, National Institutes of Health Stroke Scale, and Euro-QoL 5 dimensions visual analog scales. We assessed discriminative validity (associations between SF-SIS and factors known to influence outcome [age, physiological parameters, and comorbidity]). We assessed face validity and acceptability by sharing the SF-SIS with a focus group of stroke survivors and multidisciplinary stroke healthcare staff. From 5549 acute study patients (mean age 68.5 [SD 13] years, mean SIS 64 [SD 32]) and 332 rehabilitation patients (mean age 65.7 [SD 11] years, mean SIS 61 [SD 11]), we derived an 8-item SF-SIS that demonstrated good agreement with original SIS and good correlation with our chosen functional and quality of life measures (all ρ>0.70, P<0.0001). Significant associations were seen with our chosen predictors of stroke outcome in the acute group (P<0.0001). The focus group agreed with the choice of items for SF-SIS across 7 of 8 domains.
  
  
  
  Using multiple, complementary methods, we have derived an SF-SIS and demonstrated content, convergent, and discriminant validity. This shortened SIS should allow collection of robust quality of life data with less associated test burden.
authors.affiliation: Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK.
authors.forename: Rachael
authors.initials: R
authors.lastname: MacIsaac
authors.affiliation: Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK.
authors.forename: Myzoon
authors.initials: M
authors.lastname: Ali
authors.affiliation: Nuffield Department of Population Health, University of Oxford, UK.
authors.forename: Michele
authors.initials: M
authors.lastname: Peters
authors.affiliation: School of Health Sciences, University of Newcastle, Australia.
authors.forename: Coralie
authors.initials: C
authors.lastname: English
authors.affiliation: Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Helen
authors.initials: H
authors.lastname: Rodgers
authors.affiliation: Nuffield Department of Population Health, University of Oxford, UK.
authors.forename: Crispin
authors.initials: C
authors.lastname: Jenkinson
authors.affiliation: Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK.
authors.forename: Kennedy R
authors.initials: KR
authors.lastname: Lees
authors.affiliation: Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK terry.quinn@glasgow.ac.uk.
authors.forename: Terence J
authors.initials: TJ
authors.lastname: Quinn
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D015203:Reproducibility of Results; D020521:Stroke / Q000503:physiopathology* / Q000523:psychology; D000071939:Stroke Rehabilitation; D011795:Surveys and Questionnaires
keywords: Patient‐reported outcome measures; Stroke Impact Scale; quality of life; stroke; stroke scales