RESUMO
The aim in this study was to translate and cross-culturally adapt the Genetic Counseling Outcome Scale (GCOS-24) for use in Spain and to carry out a preliminary psychometric validation in a sample of Spanish patients. With oversight by an expert panel, forward and backward translations were conducted to create the draft Spanish GCOS-24. Fourteen patients were recruited from a clinical genetics service in Madrid, Spain, to participate in cognitive interviews designed to explore readability and interpretability of the draft. Following qualitative analysis of interview transcripts, a final version of the Spanish GCOS-24 was agreed with the expert panel. No significant cross-cultural differences were identified. The Spanish GCOS-24 was then completed prior to and 2-4 weeks after genetic counseling by 59 patients attending the service, and data were analysed using analysis of variance. Preliminary psychometric validation of the Spanish GCOS-24 showed significantly higher GCOS-24 scores after genetic counseling (p < 0.0001), with good internal consistency (α = 0.84) and sensitivity to change over time, with a medium-to-large size effect (Cohen's d = 0.70). This compares well with the original English language GCOS-24. Findings demonstrate that the Spanish GCOS-24 has potential for use in evaluating clinical genetics services in Spain, but would benefit from assessment of test-retest reliability as well as structural and construct validity.