Translation and Cross-cultural Validation of Leprosy Case Detection Delay Questionnaire Among Persons Affected by Leprosy in Southeast Nigeria

Introduction Reducing delays in leprosy case detection is essential for achieving global leprosy targets. Accurate measurement of these delays and their determinants relies largely on patient-reported data, as routine health records are often inadequate. The leprosy case detection delay (CDD) questionnaire, developed under the Post Exposure Prophylaxis for Leprosy (PEP4LEP) project, has been validated in Ethiopia, Mozambique, Tanzania, and Indonesia. However, it has not been adapted or validated for Nigeria or any major Nigerian indigenous language. This study aimed to culturally adapt and validate the CDD questionnaire for Igbo-speaking populations in Nigeria. Methodology/Principal Findings The CDD questionnaire underwent a standardized cross-cultural adaptation process. Content validity was assessed using item- and scale-level content validity indices, while construct validity was evaluated through hypothesis testing. Reproducibility was assessed using test-retest and inter-rater reliability; agreement using the Bland-Altman method and the Wilcoxon Signed-Rank test; reliability using Spearmans rank correlation coefficient and the Intraclass Correlation Coefficient (ICC); and internal consistency using Cronbachs alpha. Data were collected through face-to-face interviews with persons affected by leprosy at two time points separated by at least two weeks. Participants (n=100) had a mean age of 45.1 years (SD=18.7). Mean CDD was 77.2 months at baseline and 77.9 months at retest. The instrument demonstrated excellent content validity (I-CVI/S-CVI: 0.90-1.00), good internal consistency (Cronbachs =0.77), and excellent test-retest reliability (ICC=0.996, 95% CI: 0.994-0.997). Test and retest measurements were highly correlated ({rho}=0.985, p<0.001), with no evidence of systematic change over time (p=0.864). Seventy-two percent of participants reported identical CDD values across assessments. All items from the original English version were retained without modification. Conclusion/Significance The Igbo version of the CDD questionnaire demonstrated good validity and reliability and is suitable for assessing leprosy case detection delay among Igbo-speaking populations in Nigeria