Reliability and validity of the Chinese version of the functional status score for the ICU (FSS-ICU) after translation and cross-cultural adaptation

Abstract

Purpose

The Functional Status Score for the Intensive Care Unit (FSS-ICU) is designed to assess the physical functional status of patients in ICU settings. This study aimed to translate and culturally adapt the FSS-ICU for the Chinese context and to evaluate its reliability and validity.

Methods

Following Beaton’s translation model, the original FSS-ICU was subjected to forward translation, back-translation, and synthesis. After cultural adaptation and preliminary testing, the Chinese version of the FSS-ICU was established, and then two rehabilitation therapists assessed the functional status of 51 ICU patients using this scale, evaluating its reliability and validity.

Results

The Chinese version of the FSS-ICU exhibits excellent internal consistency with a Cronbach’s alpha coefficient of 0.934. The inter-rater and intra-rater correlation coefficients are 0.995 and 0.997, respectively. Both item-level and scale-level content validity indices are 1.00. The FSS-ICU demonstrates good convergent validity with other physical function assessment tools (Medical Research Council Sum-Score, grip strength, the Intensive Care Unit Mobility Scale), with |r_s| values all above 0.5, and satisfactory discriminant validity with non-physical function assessment indicators (body mass index, blood glucose), with |r_s| values all below 0.2. Additionally, it demonstrated no ceiling or floor effects.

Conclusion

The Chinese FSS-ICU, demonstrating strong reliability and validity, can serve as an effective assessment tool for physical function in ICU patients.

IMPLICATIONS FOR REHABILITATION

• The Chinese version of the Functional Status Score for the ICU (FSS-ICU) is a robust tool for assessing physical function in ICU settings in China, characterized by high reliability and validity.

• As in other countries, the FSS-ICU may be used as part of clinical care and clinical research when evaluating ICU patients’ physical status.

• This instrument facilitates tracking the progression of physical capabilities and tailoring targeted rehabilitation plans.

Keywords:

• Functional status score
• intensive care unit
• reliability
• validity
• Chinese

Acknowledgements

The authors are grateful to all patients who participated in this study. In addition, we would like to extend our special thanks to the collaborators who participated in the forward and backward translation and cross-cultural adaptation of the scale: Hong Shan Lin, Dan Yu, He Ye, Ke Tang Huang; and to the experts in the field who contributed to the translation and cross-cultural adaptation: Cai Jiang, Jin Yi He, Xiu Ling Shang, Han Chen, Qiao Ling Chen, Lan Shi, Zhong Hua Lin, and Fan Lin.

Ethical approval and consent to participate

The Institutional Review Board approved this study’s protocol (approval no. k2021-04-004). Prior to enrolment, all patients received information regarding the study’s objectives and methods, and written informed consent was obtained from each participant. The study adhered to the ethical standards of the institutional and/or national research committees, aligning with the 1964 Helsinki Declaration and its subsequent modifications, or equivalent ethical norms.

Authors’ contributions

HL: study concept design, data acquisition, data analysis, and manuscript writing and revising. TTW: study concept design, data analysis, and manuscript writing and revising. QPS: data acquisition and data analysis. JX: study concept design and data analysis. SH: study concept design, manuscript revising, and final approval. DN: co-creator of the original FSS-ICU scale, study concept design, manuscript revising, and final approval.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by Guidance project of Fujian Provincial Science and Technology Department, China (NO: 2021Y0051).