The Spanish version of the SRS-22 patient questionnaire for idiopathic scoliosis: transcultural adaptation and reliability analysis.

STUDY DESIGN: Validation of the transcultural adaptation of a questionnaire for measuring health-related quality of life.

OBJECTIVES: To translate and culturally adapt the SRS-22 questionnaire to Spanish. To determine the metric qualities (internal consistency and test-retest reproducibility) of this questionnaire.

SUMMARY OF BACKGROUND DATA: The SRS-22 Patient Questionnaire has proven to be a valid instrument for clinical assessment of patients with idiopathic scoliosis. The widespread use of the SRS-22 in non-English-speaking countries requires its transcultural adaptation.

METHODS: Transcultural adaptation of the SRS-22 was carried out according to the International Quality of Life Assessment Project guidelines and included two translations and two back-translations of the material. A committee of experts decided on the final version. The questionnaire was administered to 175 individuals (152 women and 23 men) with idiopathic scoliosis. The mean age of the participants at the time they received the questionnaire was 18.9 years, thoracic curve magnitude was 28.8 degrees, and lumbar curve magnitude was 28.1 degrees. At this time, 85 patients had been treated surgically, 45 had been treated with orthesis, and 45 were under observation. A subgroup of 30 patients completed the questionnaire a second time 1 week later. Internal consistency was determined with Cronbach's alpha coefficient and test-retest reliability with the intraclass correlation coefficient.

RESULTS: The overall alpha coefficient of the questionnaire was 0.89. Coefficients for individual domains were as follows: function/activity, 0.67; pain, 0.81; mental health, 0.83; self-image, 0.73; and satisfaction, 0.78. The questionnaire as a whole had an intraclass correlation coefficient of 0.96. Intraclass correlation coefficients for individual domains were as follows: pain, 0.93; function, 0.82; self-image, 0.94; mental health, 0.94; and satisfaction, 0.98.

CONCLUSIONS: The Spanish version of the SRS-22 Patient Questionnaire demonstrated adequate internal consistency for the majority of domains and excellent reproducibility. These results suggest that the process of adaptation has produced an instrument that is apparently equivalent to the original and suitable for clinical research.