Background and Objectives: To assess the reliability and construct validity of the Functional Rating Index (FRI) in Italian-speaking individuals with chronic non-specific low back pain (CLBP), in order to improve assessment and clinical management in this population. Materials and Methods: This cross-sectional study consecutively enrolled 75 individuals with CLBP (52 females; mean age 48.71 ± 19.18 years; mean pain duration 298.64 ± 427.52 weeks). Internal consistency and test–retest reliability were evaluated using Cronbach’s α and the intraclass correlation coefficient [ICC2,1], respectively, while measurement error was estimated through the minimum detectable change (MDC). Construct validity was examined by testing a priori hypotheses through correlations (Pearson’s r) between the FRI and disability measures (Roland–Morris Disability Questionnaire, RMQ; Oswestry Disability Index, ODI), pain intensity (Numerical Rating Scale, NRS), and quality of life (Short-Form Health Survey, SF-36). Results: Cronbach’s α was 0.88, and test–retest reliability showed an ICC2,1 of 0.86 (95%CI: 0.82–0.93). The MDC was 18.05, corresponding to approximately 20% of the total score. The Italian FRI demonstrated strong correlations with the RMQ (r = 0.70) and ODI (r = 0.77), and a moderate correlation with the NRS (r = 0.60). The physical and social domains of the SF-36 showed stronger negative correlations with the FRI than the mental and emotional domains. Conclusions: The Italian version of the FRI is a reliable and valid instrument for individuals with CLBP and is recommended for both clinical practice and research applications.
Reliability, Minimum Detectable Change and Construct Validity of the Functional Rating Index in Italian Patients with Chronic Non-Specific Low Back Pain
Paolucci T.Primo
;Pezzi L.Secondo
;Pantalone A.;Palumbo R.;Di Deo Iurisci R.;Cichelli A.
;
2026-01-01
Abstract
Background and Objectives: To assess the reliability and construct validity of the Functional Rating Index (FRI) in Italian-speaking individuals with chronic non-specific low back pain (CLBP), in order to improve assessment and clinical management in this population. Materials and Methods: This cross-sectional study consecutively enrolled 75 individuals with CLBP (52 females; mean age 48.71 ± 19.18 years; mean pain duration 298.64 ± 427.52 weeks). Internal consistency and test–retest reliability were evaluated using Cronbach’s α and the intraclass correlation coefficient [ICC2,1], respectively, while measurement error was estimated through the minimum detectable change (MDC). Construct validity was examined by testing a priori hypotheses through correlations (Pearson’s r) between the FRI and disability measures (Roland–Morris Disability Questionnaire, RMQ; Oswestry Disability Index, ODI), pain intensity (Numerical Rating Scale, NRS), and quality of life (Short-Form Health Survey, SF-36). Results: Cronbach’s α was 0.88, and test–retest reliability showed an ICC2,1 of 0.86 (95%CI: 0.82–0.93). The MDC was 18.05, corresponding to approximately 20% of the total score. The Italian FRI demonstrated strong correlations with the RMQ (r = 0.70) and ODI (r = 0.77), and a moderate correlation with the NRS (r = 0.60). The physical and social domains of the SF-36 showed stronger negative correlations with the FRI than the mental and emotional domains. Conclusions: The Italian version of the FRI is a reliable and valid instrument for individuals with CLBP and is recommended for both clinical practice and research applications.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
