Clinimetric instruments to assess functional health status in patients with haemophilia: a literature review.

The World Federation of Hemophilia scoring system (WFH-1) evaluates primarily body functions and structures, whereas assessment of the whole area of functional health status is considered nowadays to be a better measure. In addition, the WFH-1 lacks psychometric properties (reliability, validity and sensitivity to change). This study aimed to gain insight into the clinimetric assessment of functional health status in patients with haemophilia by way of a systematic literature search. A standardized literature search and selection was performed on the databases of CINAHL (1982-2001), Medline (1966-2001), and PubMed (January-July 2001). Clinimetric instruments applied in the selected articles were classified based on the international classification of functioning, disability, and health (ICF) and analysed for their psychometric properties. In 19 articles published between 1979 and 2001, 34 clinimetric instruments were used to assess functional health status. Instruments were classified as measuring the ICF components body structure and function (n = 17), activities (12) and participation (4). Reliability was measured in four articles on three different instruments, the validity (construct) of the instruments for patients with haemophilia was reported in six articles on five instruments, and sensitivity to change in three articles on three instruments. The populations under study varied in number (7-9 35), mean age (21.6-50.8 years), and in the distribution of haemophilia severity. Reports on the evaluation of functional health status in patients with haemophilia are increasing. Further research on the psychometric properties of the instruments is warranted in more groups of patients with haemophilia. Development of the new core set of clinimetric instruments, the WFH-2, might benefit from this strategy.