Methodological considerations in cross-sectional studies validating the International Classification of Functioning,...

To describe and analyze the methodological characteristics and quality of cross-sectional studies that have validated an ICF-CS.

A systematic review was conducted to identify empirical studies published in English that validated any ICF-CS using a cross-sectional design. Databases searched included Web of Science, Scopus, CINAHL, PubMed, Embase, and PsycINFO. The search was conducted in November 2022 with an update in October 2023. Two independent reviewers coded studies that met the inclusion criteria and assessed their methodological quality and risk of bias using the AXIS tool. Synthesis was performed by calculating frequencies and percentages.

87 articles validating 24 ICF-CSs were analyzed. Most articles showed strengths in consistency between study objectives and the outcome variables measured. However, a large majority did not report sample size calculation (up to 94.2% in Delphi studies), and few validation studies were conducted in the WHO regions of Africa and the Eastern Mediterranean.

The quality of cross-sectional studies validating ICF-CSs was satisfactory, although several articles did not describe aspects such as sample size calculation. Validity evidence for ICF-CS studies could be improved by conducting more multicenter studies, replicating ICF-CS validation studies in different WHO regions, and through synthesis of existing research.