Transculturalization and validation of a Spanish translation of the specific lower limb osteoarthritis and quality of life questionnaire AMICAL: Arthrose des Membres Inférieurs et Qualité de vie AMIQUAL.

INTRODUCTION: Several generic questionnaires have been used to measure quality of life in patients with Osteoarthritis (OA) since few instruments have been developed specifically for OA and none was developed for Spanish speaking patients. The purpose of the study was to validate and adapt to Spanish the French questionnaire AMICAL to measure quality of life in patients with hip and knee OA.

METHODS: Transversal, analytical study. The validation process was performed in phases: translation from French to Spanish, translated version analysis by a multidisciplinary expert team, application of a pilot test to patients to evaluate grammatical and content equivalence, blind back translation, and analysis. The questionnaire was applied to hip and knee OA patients, together with the SF-36 questionnaire, as well as the WOMAC and the Lequesne indexes. The reproducibility was evaluated applying the questionnaire after 72hours. The clinimetric analysis was calculated with SPSS 16.0.

RESULTS: One hundred patients with hip OA and 100 patients with knee OA, radiological stages ii-iii, were included to evaluate homogeneity. Sixty-five patients with hip OA and 65 patients with knee OA were included to evaluate consistency. The final sample included 100 hip and 100 patients knee OA patients to estimate homogeneities and 65 patients were evaluated to estimate consistency. Mean (SD) age of patients with hip and knee OA, was 56.34 ± 13 and 60.1 ± 9.2, respectively. Sixty seven percent and 79.8% were female, respectively. Cronbach' alpha for AMICAL was 0.946 and 0.999, for hip OA and knee OA, respectively; and test-retest reliability using the intraclass correlation coefficients was 0.979 and 0.998, respectively. There was also a significant correlation with all the instruments (P<.05), except with the Lequesne index (r-0.383).

CONCLUSIONS: The Spanish version of AMICAL questionnaire keep the clinimetric properties, homogeneity, and consistency, and has a good correlation with other instruments. Consequently, it is reliable, self-applicable, and includes domains beyond the functional capacity that better evaluate the quality of life.