Health and Quality of Life Outcomes (May 2018)

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

  • Hamid Reza Mokhtarinia,
  • Azadeh Hosseini,
  • Azam Maleki-Ghahfarokhi,
  • Charles Philip Gabel,
  • Majid Zohrabi

DOI
https://doi.org/10.1186/s12955-018-0928-5
Journal volume & issue
Vol. 16, no. 1
pp. 1 – 9

Abstract

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Abstract Background There are various instruments and methods to evaluate spinal health and functional status. Whole-spine patient reported outcome (PRO) measures, such as the Spine Functional Index (SFI), assess the spine from the cervical to lumbo-sacral sections as a single kinetic chain. The aim of this study was to cross-culturally adapt the SFI for Persian speaking patients (SFI-Pr) and determine the psychometric properties of reliability and validity (convergent and construct) in a Persian patient population. Methods The SFI (English) PRO was translated into Persian according to published guidelines. Consecutive symptomatic spine patients (104 female and 120 male aged between 18 and 60) were recruited from three Iranian physiotherapy centers. Test-retest reliability was performed in a sub-sample (n = 31) at baseline and repeated between days 3–7. Convergent validity was determined by calculating the Pearson’s r correlation coefficient between the SFI-Pr and the Persian Roland Morris Questionnaire (RMQ) for back pain patients and the Neck Disability Index (NDI) for neck patients. Internal consistency was assessed using Cronbach’s α. Exploratory Factor Analysis (EFA) used Maximum Likelihood Extraction followed by Confirmatory Factor Analysis (CFA). Results High levels of internal consistency (α = 0.81, item range = 0.78–0.82) and test-retest reliability (r = 0.96, item range = 0.83–0.98) were obtained. Convergent validity was very good between the SFI and RMQ (r = 0.69) and good between the SFI and NDI (r = 0.57). The EFA from the perspective of parsimony suggests a one-factor solution that explained 26.5% of total variance. The CFA was inconclusive of the one factor structure as the sample size was inadequate. There were no floor or ceiling effects. Conclusions The SFI-Pr PRO can be applied as a specific whole-spine status assessment instrument for clinical and research studies in Persian language populations.

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