Abstract W MP103: Describing Clinimetric Properties of the Stroke Impact Scale
Background and purpose: The Stroke Impact Scale (SIS) is an eight domain (59 item) quality of life scale prevalent in the literature, a short form with physical function focus (SIS-16) is also described. These stroke specific scales may have utility but we should not assume favorable properties. We examined clinimetrics of SIS and SIS-16.
Methods: We used patient-level data contained in the Virtual International Stroke Trial Archive (VISTA). For all patients with SIS/SIS-16 we extracted and standardised corresponding clinical and demographic data. We described internal consistency (Cronbach’s alpha) of scales and component sub-domains. We compared SIS to SIS-16 and described correlations with other outcomes. We compared individual SIS domains to scales measuring similar constructs.
Results: Using SIS data, n=332 (mean age 65.7 [SD:11]; mean SIS:61 [SD:11]). Internal consistency of SIS was excellent α:0.93. SIS domains agreed with total SIS, poorest agreement was for emotion α:0.63. SIS correlated with BI (r=0.72, p<0.0001); EQ-5D (r=0.69, p<0.0001) and a visual analogue scale (r=0.58, p<0.0001); agreement with SIS-16: α:0.918. SIS domains correlated with some equivalent scales.(table, *data measured at 4 month post ictus) For SIS-16, n=4310, mean age:68.5 (SD:13); mean SIS-16:64 (SD:32); α:0.98; emotion domain had poorest agreement with total SIS-16 α:0.66. SIS-16 correlated with mRS (-0.87 (p<0.0001) and BI (0.89 (p<0.0001)).
Conclusions: SIS and SIS-16 show reasonable, but not perfect, construct and congruent validity. Internal consistency of emotion domain is problematic. High internal consistency, even for SIS-16, suggests redundancy and scope to further shorten SIS while maintaining clinimetric properties.
Author Disclosures: R.L. Fulton: None. M. Ali: None. C. English: None. H. Rodgers: None. K.R. Lees: None. T.J. Quinn: None.
- © 2015 by American Heart Association, Inc.