The Vellore Pain Impact Questionnaire (V-PIQ): Initial validation of a tool for assessing the impact of low back pain based on the brief ICF core set

Objective To develop and validate the Vellore Pain Impact Questionnaire to assess the impact of low back pain in the Indian context. Design A cross-sectional, quantitative study with two phases: development and validation of the Vellore Pain Impact Questionnaire. Content validity was ensured through a Delphi process involving five occupational therapists, while reliability and criterion validity were assessed. Setting The study was conducted at the Occupational Therapy outpatient unit of a tertiary care teaching hospital in South India. Participants Sixty-five patients aged 18 years and above with nonspecific low back pain persisting for at least 12 weeks were recruited through convenience sampling. Intervention Not applicable. Main Measures The Vellore Pain Impact Questionnaire underwent inter-rater and test-retest reliability using the intraclass correlation coefficient. Criterion validity was evaluated against the Oswestry disability index. Results The Vellore Pain Impact Questionnaire showed excellent content validity (content validity index: 0.96). It demonstrated high reliability, with inter-rater (intraclass correlation coefficient: 0.985) and test-retest (intraclass correlation coefficient: 0.973) scores. The receiver operating characteristic analysis indicated moderate criterion validity (area under the curve: 0.628) compared to the Oswestry disability index. The questionnaire's broader coverage of ICF categories, including psychological and environmental factors, highlights its ability to capture the multidimensional impact of low back pain. Conclusions The Vellore Pain Impact Questionnaire shows promise as a reliable and culturally relevant tool for assessing low back pain impact in India, addressing physical, psychological, and social factors. However, further studies are necessary to establish its validity across diverse populations and settings.