Back Pain and Body Posture Evaluation Instrument (BackPEI): development, content validation and reproducibility
Following a search conducted in several databases, no instrument was found that jointly evaluates the prevalence of back pain and its associated demographic, social–economic, hereditary, behavioral and postural risk factors. Thus, the present study aims to develop the Back Pain and Body Posture Evaluation Instrument (BackPEI) for school-age children and verify its validity and reproducibility. Twenty-one questions were elaborated to compose the BackPEI instrument, eight experts checked the content validity, and its reproducibility was tested by applying the questionnaire to 260 primary schoolchildren, at two different times with a 7-day interval. The reproducibility data for the first 20 questions, analyzed using the kappa (k) coefficient, were classified as “very good” (k > 0.8) or “good” (0.6 < k ≤ 0.8). The reproducibility data for the pain intensity question, analyzed using the Wilcoxon test and the intraclass correlation coefficients (ICC), demonstrated that there was no difference between the averages (p = 0.251) and the responses were highly correlated (ICC = 0.937) for these two tests. The BackPEI constitutes a valid and reproducible instrument which is relevant for the evaluation of back pain and its associated risk factors.