Background and purpose: In view of the growing therapeutic options in stroke, measurement of quality of life has become increasingly relevant as an outcome parameters. The Sickness Impact Profile (SIP) is one of the most widely used measures to assess quality of life. To overcome the major disadvantage of the SIP, its length, we constructed a short stroke adapted 30-item SIP version (SA-SIP30).
Methods: Data on the original SIP version were collected for 319 communicative patients at 6 months after stroke. The 12 subscales and the 136 items of the original SIP were reduced to 8 subscales with 30 items in a three step procedure, on the basis of relevancy and homogeneity. Reliability of the SA-SIP30 was evaluated by means of an analysis of homogeneity (Cronbach's alpha coefficient). Different types of validity were assessed: construct, clinical, and external validities.
Results: Homogeneity of the SA-SIP30 was demonstrated by a high Cronbach's alpha (0.85). Principal component analyses revealed the same two dimensions as in the original SIP (a physical and a psychosocial dimension). The SA-SIP30 could explain 91% of the variation in scores of the original SIP in the same cohort of patients, and 89% in a different cohort. Furthermore, the SA-SIP30 was related to other functional health measures similar to how the original SIP was. We could demonstrate that the SA-SIP30 was able to distinguish patients with lacunar infarctions from patients with cortical or subcortical lesions.
Conclusions: We conclude that the SA-SIP30 is a feasible and clinimetrically sound measure to assess quality of life after stroke.