Explanatory power does not equal clinical importance: study of the use of the Brief ICF Core Sets for Spinal Cord Injury with a purely statistical approach

Study design: Psychometric study analyzing the data of a cross-sectional, multicentric study with 1048 persons with spinal cord injury (SCI). Objective: To shed light on how to apply the Brief Core Sets for SCI of the International Classification of Functioning, Disability and Health (ICF) by determining whether the ICF categories contained in the Core Sets capture differences in overall health. Methods: Lasso regression was applied using overall health, rated by the patients and health professionals, as dependent variables and the ICF categories of the Comprehensive ICF Core Sets for SCI as independent variables. Results: The ICF categories that best capture differences in overall health refer to areas of life such as self-care, relationships, economic self-sufficiency and community life. Only about 25% of the ICF categories of the Brief ICF Core Sets for the early post-acute and for long-term contexts were selected in the Lasso regression and differentiate, therefore, among levels of overall health. Conclusion: ICF categories such as d570 Looking after one's health, d870 Economic self-sufficiency, d620 Acquisition of goods and services and d910 Community life, which capture changes in overall health in patients with SCI, should be considered in addition to those of the Brief ICF Core Sets in clinical and epidemiological studies in persons with SCI. Spinal Cord (2012) 50, 734-739; doi:10.1038/sc.2012.40; published online 24 April 2012