[Cross cultural adaptation of a health related quality of life measurement: the Spanish version of the COOP/WONCA cartoons].

OBJECTIVES: Cross-cultural adaptation to Castilian Spanish of the original COOP/WONCA charts questionnaire and its validation for use in Spain.
DESIGN: Descriptive crossover study.
SETTING: Primary Care. PATIENTS: Pilot test with a consecutive sample of 63 patients from a medical list. The final version was administered to a random sample of 475 patients from five medical lists of two urban Health Centres.
MEASUREMENTS AND MAIN RESULTS: The adaptation was based on the method of translations and independent back-translations by bilingual persons, from the original version of the instrument and performance of the pilot test. The conceptual equivalence between the final version and the original questionnaire was satisfactory in 8 of the 9 items. Mean scores of the semantic and syntactic equivalences were high and equally satisfactory. Cronbach's alpha was above 0.7 for 6, 7 and 9 items. Spearman's correlation coefficients between two administrations of the questionnaire, separated by 15 days, scored between 0.52 and 0.72. The factorial analysis of 6, 7 and 9 items revealed a unifactorial structure. All the load values ranged between 0.5 and 0.8 except item 5.
CONCLUSIONS: The adaptation of the COOP/WONCA charts questionnaire finished with an instrument apparently equivalent to the original and with acceptable reliability and validity. However, other basic characteristics such as sensitivity to changes need to be explored, and aspects of construct validity examined more closely.