Design and preliminarily validation of a tool to assess the impact of chronic non-cancer pain on people’s daily life in Spanish-language: PAIN_Integral Scale

Abstract

Aim: To build and preliminarily validate a Spanish-language instrument to assess the impact that CNCP has on the daily lives of people who suffer from it. Background: The experience of pain is multifactorial and a correct assessment of it helps to control the intensity of pain. Although there are instruments that evaluate areas on which Chronic Non-Cancer Pain impacts, it would be necessary to include other aspects that scientific literature identifies as relevant. Design: Instrument and construct cross-sectional study for psychometric validation. Methods: A total of 157 items based on items from validated questionnaires were evaluated by a group of 21 chronic pain experts using Delphi methodology in three evaluation rounds. A final questionnaire of 55 items with a 5-point Likert-type scale was formed. This questionnaire was piloted on a total of 30 patients to assess their understanding of the items and the psychometric validation process was carried out (January to March 2020) on a subsequent sample of 395 people, all of whom attended Pain Units and Primary Care Centres of the Public Health System in Spain. Results: The PAIN_Integral Scale© showed acceptable internal consistency scores measured by Cronbach's alpha. Exploratory Factor Analysis indicated a structure of nine factors that explain 71.02% of the total variance, from 157 to a final total of 36 items. Confirmatory Factor Analysis showing adequate values confirmed this structure. The effect size was used to calculate the cut-off points for the overall scale, setting them at scores of 130 and 135. Conclusion: This instrument would allow to assess other constructs and dimensions not included in the instruments previously available such as treatment compliance, proactivity, resilience, hopelessness due to pain and pain catastrophizing. However, despite the fact that the preliminary analysis shows good results, it is necessary to continue with its validation process in subsequent studies.