The ASAS Health Index and Environmental Factors Item Set: validity and reliability of the Swedish translations in Swedish patients with ankylosing spondylitis

Abstract

Objectives

To translate the Assessment of SpondyloArthritis international Society (ASAS) Health Index (HI) Environmental Factors Item Set (EFIS) into Swedish and culturally adapt it for a Swedish context, and to assess the construct validity of the Swedish version of the ASAS HI and test–retest reliability in ASAS HI and EFIS in Swedish patients with ankylosing spondylitis (AS).

Method

Translation and cross-cultural adaptation of the EFIS were carried out according to a forward–backward procedure consisting of five steps. The construct validity of the ASAS HI was tested using Spearman correlation with standard health outcomes for axial spondyloarthritis (axSpA). Reliability was analysed by internal consistency with the Cronbach’s alpha coefficient for ASAS HI, and test–retest reliability with intraclass correlation coefficients (ICCs) for ASAS HI and kappa agreement for the individual items of EFIS.

Results

The translation of EFIS showed acceptable face and content validity. ASAS HI showed an acceptable internal consistency (Cronbach’s alpha 0.79), and excellent test–retest reliability (ICC 0.87). Test–retest reliability for EFIS showed varied results, with kappa agreement for the individual items ranging from poor (−0.027) to good (0.80).

Conclusions

The Swedish version of ASAS HI proved to be valid and reliable and is recommended for assessing the impact of AS on global functioning and health. A Swedish version of EFIS has been produced and uploaded on the ASAS website. The EFIS proved to have acceptable face and content validity, and may contribute to the contextual interpretation of the ASAS HI.

Acknowledgements

The authors thank all patients who participated in the study. We also thank the professional translators, Ulrika Stigeborn Hernelid at Lingualista and Jennifer Evans at Changeling Translations AB, and the Clinical Rheumatology Research Center (KRF) at the Rheumatology Clinic at Sahlgrenska University Hospital.

Disclosure statement

No potential conflict of interest was reported by the authors.

Author contributions

The study design and protocol were developed by HFd’E and CF in collaboration with UK. Translation was performed by CF, Ad’E, and HFd’E, and data collection was carried out by CF, MH, and AD. Data interpretation and analysis were carried out, and the first draft of the manuscript was written by CF and HFd’E. All authors were responsible for critical revision and finalizing of the manuscript. All authors read and approved the final manuscript.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/03009742.2023.2266903.

Additional information

Funding

This work was supported by grants from the Swedish state under the agreement between the Swedish government and the county councils, the ALF agreement [ALFGBG-938395, ALFGBG-965333], King Gustaf Vth 80-year Foundation [FAI-2017-0454], the Swedish Association Against Rheumatism, the Amlövs Foundation, the Inger Bendix Foundation for Medical Research, and the Margareta Rheumatology Research Foundation.