DEVELOPMENT AND PSYCHOMETRIC VALIDATION OF THE COST-OF-ILLNESS QUESTIONNAIRE
Author(s)
Saroj K. Bharti, PhD1, Dipika Bansal, MD2, Jitendra Kumar Sahu, MBBS, MD, DM3;
1NIPER Mohali, PhD Scholar, SAS Nagar, India, 2National Institute of Pharmaceutical Education and Research, Mohali, India, 3PGIMER Chandigarh, Chandigarh, India
1NIPER Mohali, PhD Scholar, SAS Nagar, India, 2National Institute of Pharmaceutical Education and Research, Mohali, India, 3PGIMER Chandigarh, Chandigarh, India
OBJECTIVES: This study aimed to develop and validate a region-specific Cost-of-Illness Questionnaire for Pediatric Epilepsy
METHODS: A multi-phase, mixed-methods approach was employed. First, a systematic literature review identified 24 relevant studies to generate an initial item pool. This was followed by iterative internal and external Delphi consensus rounds. The internal panel included five experts, while the external panel comprised 18 experts from multiple South Asian countries and one health policymaker from the United States, whose inputs enhanced content clarity, contextual appropriateness, and international relevance. Items with an Item-Level Content Validity Index (I-CVI) below 0.50 were revised or excluded. The finalized questionnaire underwent psychometric evaluation in a prospective cross-sectional study conducted at PGIMER, Chandigarh, involving 41 caregivers of children with epilepsy. Internal consistency was assessed using Cronbach’s alpha, and test-retest reliability was examined using intraclass correlation coefficients (ICC)
RESULTS: The Delphi process resulted in a 67-item questionnaire spanning five domains: sociodemographic profile, direct medical costs, direct social costs, indirect costs, and intangible costs. All retained items demonstrated acceptable content validity (I-CVI > 0.50). Internal consistency ranged from acceptable to excellent across domains (α = 0.70-0.86), while test-retest reliability showed strong temporal stability (ICC = 0.79-0.88). Factor analysis showed limited sampling adequacy (KMO = 0.382), reflecting the inherent multidimensionality and heterogeneity of cost constructs in pediatric epilepsy.
CONCLUSIONS: This Questionnaire is the first validated, South Asia-specific instrument for comprehensive assessment of COI in pediatric epilepsy. With strong content validity, reliable measurement properties, and contextual relevance, it offers a robust tool for research, economic evaluation, and policy planning in LMIC settings. Further validation across diverse South Asian populations is warranted.
METHODS: A multi-phase, mixed-methods approach was employed. First, a systematic literature review identified 24 relevant studies to generate an initial item pool. This was followed by iterative internal and external Delphi consensus rounds. The internal panel included five experts, while the external panel comprised 18 experts from multiple South Asian countries and one health policymaker from the United States, whose inputs enhanced content clarity, contextual appropriateness, and international relevance. Items with an Item-Level Content Validity Index (I-CVI) below 0.50 were revised or excluded. The finalized questionnaire underwent psychometric evaluation in a prospective cross-sectional study conducted at PGIMER, Chandigarh, involving 41 caregivers of children with epilepsy. Internal consistency was assessed using Cronbach’s alpha, and test-retest reliability was examined using intraclass correlation coefficients (ICC)
RESULTS: The Delphi process resulted in a 67-item questionnaire spanning five domains: sociodemographic profile, direct medical costs, direct social costs, indirect costs, and intangible costs. All retained items demonstrated acceptable content validity (I-CVI > 0.50). Internal consistency ranged from acceptable to excellent across domains (α = 0.70-0.86), while test-retest reliability showed strong temporal stability (ICC = 0.79-0.88). Factor analysis showed limited sampling adequacy (KMO = 0.382), reflecting the inherent multidimensionality and heterogeneity of cost constructs in pediatric epilepsy.
CONCLUSIONS: This Questionnaire is the first validated, South Asia-specific instrument for comprehensive assessment of COI in pediatric epilepsy. With strong content validity, reliable measurement properties, and contextual relevance, it offers a robust tool for research, economic evaluation, and policy planning in LMIC settings. Further validation across diverse South Asian populations is warranted.
Conference/Value in Health Info
2026-05, ISPOR 2026, Philadelphia, PA, USA
Value in Health, Volume 29, Issue S6
Code
EE381
Topic
Economic Evaluation
Disease
SDC: Neurological Disorders, SDC: Pediatrics