Purpose: The purpose of this paper was to translate and validate into the Korea language and setting the Sarcopenia Quality of Life (SarQoL®) questionnaire.
Methods: The participants consisted of 450 individuals in Namgaram-2 cohort who were followed up in 2019-2020. The study participants were divided into four groups: (1) SARC-F < 4, (2) SARC-F ≥ 4 and robust grip strength, (3) SARC-F ≥ 4, low grip strength, robust muscle mass, (4) SARC-F ≥ 4, low grip strength, and low muscle mass. To assess construct validity, population with sarcopenia-associated symptoms (SARC-F ≥ 4) apart from the Korean SarQoL (SarQoL-K®) completed the Korean versions of two generic questionnaires, the Short Form-36 and the EuroQoL 5-dimension. To validate the Korean SarQoL®, we assessed its validity (discriminative power, construct validity), reliability (internal consistency, test-retest reliability), and floor/ceiling effects.
Results: The SarQoL-K® questionnaire was translated without major difficulties. The mean SarQoL-K scores were 72.9 (95%, CI; 71.2-74.6) in SARC-F < 4, 54.6 (95%, CI; 50.7-58.3) in SARC-F ≥ 4 and robust grip strength, 47.0 (95%, CI; 43.8-50.1) in SARC-F ≥ 4, low grip strength, robust muscle mass, 46.6 (95%, CI; 43.0-50.1) in SARC-F ≥ 4, low grip strength, and low muscle mass. The results indicated good discriminative power across each four groups (p < 0.001), high internal consistency (Cronbach's alpha of 0.866), and excellent test-retest reliability (ICC = 0.977, 95% CI 0.975-0.979). No floor- or ceiling-effects were observed.
Conclusions: This is the first study to confirm the reliability and validity of the Korean version of the SarQoL®. We demonstrated that the population with sarcopenia-associated symptoms (determined using the SARC-F questionnaire) has a lower quality of life.
Keywords: Cross cultural adaptation; Korea; Quality of life; Sarcopenia.