Translation and Validation of 'Foot Health Status Questionnaire' in Dutch.

The aim of our study was to develop a Dutch version of the Foot Health Status Questionnaire (FHSQ-NL) and evaluate its measurement properties according to the COSMIN definition (COnsensus-based Standards for the selection of health Measurement INstruments). After translation of the FSHQ, a group of 119 randomly selected patient who visited the outpatient clinic for conditions affecting the foot and ankle were asked to participate, of which103 patients were included in the analysis. The FHSQ-NL, a validated Dutch FAOS and a visual analogue scale (VAS) for pain and function were used in this study as outcomes measures. Reliability was assessed by calculating intraclass correlation coefficient (ICC), internal consistency by Cronbach's alpha, and the smallest detectable change (SDC). Construct validity was evaluated by use of a priori hypotheses concerning Spearman's correlation coefficient between FHSQ subscales and FAOS and VAS. All domains of the FHSQ-NL, besides 'General health,' indicated good internal consistency with a Cronbach's alpha ranging from 0.61 to 0.91. Test-retest reliability of all FHSQ domains was poor with an ICC ranging from 0.47 to 0.77. At individual level, the SDC ranged from 35.1 to 60.6 and at a group level (n = 50) from 5.0 to 8.6. Construct validity was supported by confirmation of 75% of all a priori hypotheses. The FHSQ-NL has good internal consistency and smallest detectable change (SDC) at group level. However, reliability and SDC on individual level show suboptimal results. Therefore, the questionnaire is more suitable for evaluating foot complaints at group level instead of individual level.