Cross-cultural adaptation and validation of Sarcopenia and Quality of Life (SarQoL) in Brazil

ABSTRACT BACKGROUND: Sarcopenia is defined as a slow, progressive, and apparently inevitable process of involuntary loss of muscle mass, strength, and quality, which occurs with advancing age. It is widely accepted that sarcopenia can directly affect quality of life. OBJECTIVE: Translate, adapt and validate the “Sarcopenia and Quality of Life” instrument (SarQoL) to the Brazilian context. DESIGN AND SETTINGS: Translation, cross-cultural adaptation, and validation study carried out at the Federal University of São Carlos, São Carlos, São Paulo, Brazil. METHODS: The population consisted of 221 older adult participants. The steps recommended by the guidelines from the authors of the original instrument were followed sequentially: initial translation, synthesis of translations, backward translation, evaluation by a panel of judges, pre-test, and analysis of psychometric properties. The translation and adaptation process was conducted as recommended. RESULTS: Two hundred and twenty-one participants took part in the step analysis of the psychometric properties of SarQoL, in which 55 presented sarcopenia. Cronbach's alpha coefficient of the total SarQoL questionnaire was 0.976, indicating excellent internal consistency. Excellent agreements between the test and retest with an Interclass Correlation Coefficient (ICC) of 0.983 (95% confidence interval: 0.901–0.996) were observed in the SarQoL domains. The domains of Short-Form 36 and EuroQoL 5-dimension showed significant correlation, from moderate to strong magnitude, with SarQoL total score, indicating convergent validity. CONCLUSION: The Brazilian version of SarQoL presented evidence of reliability and validity.


INTRODUCTION
The elderly population in Brazil is rapidly increasing and is currently ranked sixth largest in the world, with more than 23 million citizens over 60 years of age, accounting for 12.6% of the Brazilian population. 1 Due to this accelerated growth, there is a considerable increase in chronic conditions related to age, such as sarcopenia, attracting the attention of many researchers in this field. 2 Sarcopenia is defined as a slow, progressive, and seemingly inevitable process of involuntary loss of muscle mass, strength, and quality, which occurs with advanced age. 3,4 To diagnose sarcopenia, according to the 2 nd European Working Group on Sarcopenia in Older People (EWGSOP2), if low muscle strength is detected, confirm sarcopenia through the amount of muscle mass and to classify it as severe sarcopenia, check physical performance. 5 Skeletal muscle dysfunction is a debilitating condition that leads to daily limitations. 6 Muscle mass, strength, and physical performance are particularly determinant of independent function in human life. [6][7][8] In a meta-analysis, sarcopenia was found to be an independent risk factor for several adverse outcomes, including dependence for instrumental and basic activities of daily living, osteoporosis, hospitalization, and death. 8 It is therefore widely accepted that sarcopenia can directly impair quality of life. [6][7][8][9] To evaluate the quality of life, specifically of people with sarcopenia, Sarcopenia and Quality of Life (SarQoL) was developed and validated in Belgium. 9,10 It consists of seven domains: physical and mental health, locomotion, body composition, functionality, activities of daily living, leisure activities, and fears. 9 Currently, SarQoL has been translated into 26 other languages including Lithuanian versions have already been validated. 11 A systematic review and meta-analysis on the prevalence of sarcopenia in Brazilian older adults returned 31 completed studies with more than nine thousand older adult patients. Results showed that 17% of older adult patients present sarcopenia, 2 meaning that instruments for assessing the specific quality of life of this group are necessary.

OBJECTIVE
To translate, culturally adapt and validate the "SarQoL" instrument in the Brazilian context.

Translation, adaptation, and validity
SarQoL has 55 items in 22 questions and includes seven domains.
Its score ranges from 0 to 100, and the higher the score, the better the quality of life. 9 SarQoL is a simple, easy-to-use instrument and takes an average time of 10 minutes to complete. It can also be self-applied. [9][10][11] It should be noted that prior to initiating the SarQoL translation, adaptation, and validation process, the authors´ permission was obtained by e-mail (Charlotte Beaudart and Olivier Bruyère -www.sarqol.org).
The following recommended steps were followed according to the protocol provided by the authors who designed the origi-  and Short Form Health Survey (SF-36), Geriatric Depression Scale, and mini nutritional assessment (MAN). After answering the aforementioned instruments, it was necessary to verify who among the older adult respondents were and were not sarcopenic.
To diagnose sarcopenia, the criteria recommended by the EWGSOP24 were adopted, in which muscle strength is assessed, sarcopenia is confirmed by muscle mass and severity determined by physical performance. 4 As evidence of sarcopenia, the measurement of handgrip strength was used, in which the criterion established by the Health, Well-being and Aging (SABE) study was adopted, which uses the cut-off score of < 30 kg for men and < 20 kg for women. 13,14 If participants had scores lower than those mentioned above, they qualified for the test of the first criterion (low strength).
To confirm sarcopenia by detecting low muscle quantity and quality, dual-energy x-ray absorptiometry (DXA) was used.
After answering the aforementioned instruments, a day and time were scheduled for the participant to perform the DXA at the Physiotherapy Department of the UFSCar, where they were picked up at their own residence and taken back after taking the test. For the cut-off values, those recommended by the SABE study were used, that is, 6.37 m²/kg for women and 8.90 m²/kg for men. 15,13 To determine the severity of sarcopenia, a gait speed test with a cut-off score of less than 0.8 m/s was used for both sexes. 3,5 The speed test was conducted at the Physiotherapy Department of the UFSCar, in which the participant did the DXA and then performed the walk test in a prepared and controlled environment.

Statistical analysis
The Kolmogorov-Smirnov test was first performed, to verify the absence of data normality. From this result, non-parametric statistical tests were adopted. In the descriptive analysis, the median values of the sociodemographic and health variables, as well as the frequency of the qualitative variables were determined. To analyze the reliability of SarQoL, the Cronbach's alpha coefficients, both for the total and the individual domains, were verified. Satisfactory internal consistency was considered for values equal to or greater than 0.7. To verify the test-retest reliability, the interclass correlation coefficient (ICC) was calculated for the total and individual SarQoL domains, with values equal to or greater than 0.7 indicating a satisfactory stability of the instrument.
For the SarQoL discriminant validity analysis between the group of the older adults with and without sarcopenia, the Mann-Whitney test was performed. To verify the discriminative power of SarQoL, a logistic regression analysis was conducted. The model was adjusted according to age and body mass index (BMI), which were the variables that presented a statistically significant difference between the groups (older adults with and without sarcopenia).

RESULTS
This study satisfactorily implemented all the steps recommended by the original authors for the SarQol translation and adaptation process. A general agreement average of 95.5% was obtained in the analysis conducted by the expert committee and there was no semantic change in the pre-test phase.
Out of the 221 older adults evaluated in the study validation process, 55 (24.8%) participants had sarcopenia and 166 (75.1%) did not fulfill the criteria to diagnose sarcopenia. Female participants predominated the sample (n = 151, 68.3%), which had an average of four years of schooling, two daily medications, and four associated diseases.
In addition, only 31 older adults consumed alcoholic beverages (14.0%) and 19 were smokers (8.6%). Respondents with sarcopenia were older, average age of 73.2 years, compared to those without, who were on average 68.0 years old (P ≤ 0.001). Regarding the BMI, the older adults with sarcopenia had lower mean values than those without, with a BMI of 25.3 kg/m² and 29.6 kg/m², respectively (P ≤ 0.001). There was no difference in gender, schooling, number of associated diseases, number of medications in use, or consumption of alcoholic beverages and cigarettes between sarcopenic and non-sarcopenic participants.

Reliability
Cronbach's alpha coefficient of the total SarQoL questionnaire was 0.976, indicating excellent internal consistency. Regarding the homogeneity of the domains of the SarQoL questionnaire, it can be observed that the values ranged from 0.622 to 0.976, also showing satisfactory internal consistency ( Table 1). Table 1 shows that all domains correlated positively and significantly with the total SarQoL score. Excellent stability of the SarQoL verified through the ICC was also observed, using the test and retest of the questionnaire, in which the ICC of 0.983 (95% confidence interval, CI: 0.901-0.996) was observed in the SarQoL total and in all its domains as well. Table 2 shows that SarQoL was able to discriminate between the older adults with and without sarcopenia, in all domains of QoL, as well as the total SarQoL.

Discriminant validity
The older adults with sarcopenia had an average total score of 55.5 (± 18.67), compared to a score of 74.4 (± 18.06) in the older adults without sarcopenia. In the logistic regression model for the total SarQoL score between the groups, adjusted for age and BMI, indicating a low total score in participants with sarcopenia compared to those without. In addition, in the SarQoL domain regression analyses, participants with sarcopenia also had lower scores compared to the older adults without sarcopenia ( Table 3). The discriminant power of the SarQoL questionnaire was confirmed.

Convergent construct validity
Considering the validity of the convergent, it can be observed in Table 4 that all domains of the SF-36 and the visual analog scale present in the EQ-5D correlated positively and significantly with the total SarQoL score. Given these results, the convergent construct validity of the SarQoL is confirmed.

DISCUSSION
The present study satisfactorily implemented all the steps recommended by the original authors for the SarQoL translation, adaptation, and validation process in Brazil. SarQoL has been shown to be comprehensible, consistent, reliable, and valid, and therefore may be recommended for clinical and research purposes. The questionnaire is already available in 26 different languages, with more translations underway. 10,11 Regarding internal consistency, it was observed that the     In a study correlating SarQoL with 4937 older adults in Korea through DXA and EQ-5D, they found that 6.6% of the evaluated older adults presented with sarcopenia and showed greater losses in all the domains of the EQ-5D, demonstrating that the condition directly influences the quality of life. 17 A limitation of the study is the sensitivity to change of SarQoL, which will need to be evaluated in future longitudinal and clinical intervention studies.

CONCLUSION
Based on the proposed objective and results obtained, it can be concluded that the SarQoL shows evidence of reliability and validity. SarQoL is translated, adapted, and validated in the Brazilian context, and is available for use in Brazil (www.sarqol.org).