VALIDATION DATA

All studies of the psychometric properties of the FIHOA have been done in patients with hand OA.

Cronbach’s α was 0.85 in the original study. Other studies in patients with hand OA found a Cronbach’s α ranging from 0.88 to 0.91

Test-retest reliability in several studies of patients with hand OA was good to excellent (0.74-0.96) 

Patients and rheumatologists were involved in development of the questionnaire. In a survey among 33 patients with hand OA from four countries (Belgium, the Netherlands, Spain, and the United Kingdom), 70% of patients said they thought the questionnaire adequately reflected their symptoms of physical function of the hands. However, 21% suggested some changes to the questionnaire, and a small proportion of patients (9%) even expressed that the questionnaire did not match the domain physical function and should not be used. Important problems for patients were that they felt that some important questions were missing, other items were old-fashioned, and some items were culturally challenging and (unnecessarily) sex specific.

In patients with hand OA, reported correlations of the FIHOA with other self-reported hand function instruments were at least moderate; reported correlation coefficients were 0.78 to 0.88 with the AUSCAN function, 0.52 to 0.73 with the HAQ), 0.87 to 0.89 with the CHFS, 0.80 with the AIMS2 physical, and 0.86 with the Michigan Hand Outcomes Questionnaire (MHQ). One study reported a correlation of the FIHOA with grip strength of 0.50. Correlation coefficients of the FIHOA with performance-based hand function tests were generally weaker than those with self-reported instruments; reported correlations were 0.39 with the JTHFT, 0.55 to 0.59 with the MPUT, 0.46 to 0.57 with the AHFT, and 0.53 with the HF