Cross-cultural validation of simplified Chinese version of spine functional index

Abstract

BackgroundNo effective constructs were available in mainland China to assess the whole spine function. The SFI was developed to evaluate spinal function based on the concept of a single kinetic chain concept for whole spine. The SFI has been translated to Spanish and Turkish with accepted psychometric properties. It is imperative to introduce the SFI in mainland China and further to explore the measurement properties.MethodsThe English versions of the SFI was cross-culturally translated according to international guidelines. Measurement properties (content validity, construct validity and reliability) were tested in accordance with the COSMIN checklists. A total of 271 patients were included in this study, and 61 participants with neck pain and 64 participants with back pain paid a second visit three to seven days later. Confirmatory factor analysis (CFA) and principal factor analysis (PCA) were applied to test the factor structure. The Functional Rating Index (FRI), Neck Disability Index (NDI), Oswestry Disability Index (ODI), SF-12 and a Visual Analogue Scale (VAS) were employed to evaluate the construct validity. Cronbach’s alpha and an intra-class correlation coefficient (ICC) were calculated for internal consistency and reproducibility.ResultsThe means score of SC-SFI was 63.60 in patients with spinal musculoskeletal disorders. A high response rate was acquired (265/271). No item was removed due to abnormal distribution or low item-total correlation. Results of CFA did not support that one-factor structure was in goodness of fit (CMIN/DF = 3.306, NNFI = 0.687, CFI = 0.756, GFI = 0.771 and RMSEA = 0.092). Yet, PCA suggested a one-factor structure was the best, accounting for 32% of the total variance. For structural validity, the SC-SFI correlated highly with the FRI, NDI, ODI, and PF, BP in SF-12 (r = 0.661, 0.610, 0.750, 0.709, 0.605, respectively). All the a priori hypotheses were verified. The Cronbach’s alpha for the SC-SFI was 0.91, and ICC was 0.96 (95% CI, 0.94–0.98). Bland-Altman plot also confirmed excellent test-retest reliability.ConclusionsThe SFI has been culturally adapted into SC-SFI with remarkable clinical acceptance, excellent internal consistency, reproducibility, and construct validity when applied to patients with spinal musculoskeletal disorders. The results of current study suggest that SC-SFI can be applied by physicians and researchers to measure whole-spine functional status in mainland China.Electronic supplementary materialThe online version of this article (10.1186/s12955-017-0785-7) contains supplementary material, which is available to authorized users.

Cross-cultural adaptation, validity, and reliability of the Persian version of the spine functional index

“…It was shown that the SFI-Pr had very high test-retest reliability (ICC 2.1 = 0.96) that was identical to the Spanish and Chinese versions (ICC 2.1 = 0.96) [ 22 ], very close to the original English (ICC 2.1 = 0.97) [ 9 ], but higher than both the Turkish [ 6 ] and Korean [ 23 ] (ICC 2.1 = 0.93). Further, the internal consistency (α = 0.80) was lower than the four previously reported versions including the original (α = 0.91) [ 9 ], Chinese (α = 0.91) [ 40 ], Turkish and Korean (α = 0.85) [ 6 ] and Spanish (α = 0.84) [ 22 ] but above the required threshold [ 45 ] for acceptance.…”

“…The construct validity of the SFI questionnaire was tested with EFA. The single factor solution was found in all four previous analysis of the SFI [ 6 , 9 , 22 , 40 ], however it was suggested that as some factors were notably below the loading suppression cutoff of 0.30 some items could potentially be removed. Consequently, item redundancy may be present and a shortened tool should be considered [ 6 ].…”

“…For the lumbar portion, this is lower than the Spanish ( r = 0.79) and Korean ( r = 0.75) findings for the RMQ [ 22 , 23 ]. In the Turkish and Chinese studies the ODI replaced the RMQ where correlation was r = 0.71 [ 6 ] and r = 0.75 [ 40 ] respectively. High correlation between the Persian ODI and RMQ has been shown (r = 0.71) [ 13 ], consequently our results can be indirectly compared with the previous studies [ 6 , 22 ].…”

“…The Chinese, Spanish, and Turkish versions [ 6 , 22 , 40 ] found the dominant factor accounted for respectively 32, 27.4 and 24.2% of variance. However, in each study, as in this study, only one factor had variance of > 10%.…”

“…The only available questionnaires for evaluation of the entire spine are the Bournemouth Questionnaire [ 35 , 36 ], the FRI [ 37 ] and SFI [ 9 ] with all being reported as suitable one-factor tools under EFA that ensures each can provide a single summated score [ 38 , 39 ]. The SFI can be applied in both clinical and research fields [ 6 ] and is shown to be both valid and reliable in English [ 9 ], Spanish, Chinese, Korean and Turkish [ 6 , 22 , 23 , 40 ]. The SFI has also been translated into several other languages that have yet to be published.…”