Spanish translation, cultural adaptation and validation of the SarQoL®: a specific health-related quality of life questionnaire for sarcopenia.

Background: In 2015, a specific health-related quality of life questionnaire for sarcopenia, SarQoL®, was developed and validated in French. Since then, SarQoL® has been adapted and validated in different languages. We prepared a translation, cultural adaptation and validation of the psychometric properties of the SarQoL® into Spanish.

Methods: A cross-sectional study with 86 participants. The translation and adaptation followed international guidelines with two direct translations, a synthesized version of the direct translations, two reverse translations, consensus by an expert committee of a pre-final version, pre-test by end users and final version. The discriminative power (logistic regression analyses), construct validity (Pearson and Spearman´s correlation), internal consistency (Cronbach´s alpha coefficient), test-retest reliability (intraclass correlation coefficient) and ceiling and floor effects were analyzed.

Results: The Spanish version showed good construct validity (high correlation with comparable domains of the SF-36), high internal consistency (Cronbach's alpha coefficient: 0.84) and excellent test-retest reliability (ICC: 0.967, 95%, CI 0.917 - 0.989). However, it had no discriminative power between sarcopenic and non-sarcopenic participants defined with the EWGSOP and FNIH diagnostic criteria of sarcopenia. It did show discriminative power between patients with decreased vs normal muscle strength (54.9 vs. 62.6, p 0.009) and low vs. normal physical performance (57.3 vs. 70.2; p 0.005). No ceiling or floor effect was found.

Conclusions: The Spanish version of SarQoL® has similar psychometric properties to those of the original version of the instrument. It did not discriminate between sarcopenic and non-sarcopenic patients diagnosed according to the EWGSOP or FNIH criteria, but it did with those with low muscle strength and low physical performance.