Validation of the Brazilian version of the child pain catastrophizing scale and its relationship with a marker of central sensitization.

Objectives: The Pain Catastrophizing Scale-Child version (PCS-C) allows to identify children who are prone to catastrophic thinking. We aimed to adapt the Brazilian version of PCS-C (BPCS-C) to examine scale psychometric properties and factorial structure in children with and without chronic pain. Also, we assessed its correlation with salivary levels of Brain-Derived Neurotrophic factor (BDNF).
Methods: The Brazilian version of PCS-C was modified to adjust it for 7-12 years old children. To assess psychometric properties, 100 children (44 with chronic pain from a tertiary hospital and 56 healthy children from a public school) answered the BPCS-C, the visual analogue pain scale, and questions about pain interference in daily activities. We also collected a salivary sample to measure BDNF.
Results: We observed good internal consistency (Cronbach's value = 0.81). Parallel analysis retained 2 factors. Confirmatory factor analysis of our 2-factor model revealed consistent goodness-of-fit (IFI = 0.946) when compared to other models. There was no correlation between visual analogue pain scale and the total BPCS-C score; however, there was an association between pain catastrophizing and difficulty in doing physical activities in school (p = 0.01). BPCS-C total scores were not different between groups. We found a marginal association with BPCS-C (r = 0.27, p = 0.01) and salivary BDNF levels.
Discussion: BPCS-C is a valid instrument with consistent psychometric properties. The revised 2-dimension proposed can be used for this population. Children catastrophism is well correlated with physical limitation, but the absence of BPCS-C score differences between groups highlights the necessity of a better understanding about catastrophic thinking in children.
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