Validation of an obstetric fistula screening questionnaire in rural Nepal: a community-based cross-sectional and nested case–control study with clinical examination

Objective: To validate a symptom-based fistula screening questionnaire and estimate obstetric fistula (OF) prevalence in rural Nepal. Design: Cross-sectional and nested case–control study. Setting: Sarlahi District, Nepal. Population: Parous, reproductive age women. Methods: The questionnaire assessed symptoms of vesicovaginal and rectovaginal fistula (VVF and RVF, respectively), stress and urge urinary incontinence (SUI and UUI, respectively), fecal incontinence (FI), and included interviewer observations on the smell and presence of urine and/or stool. All women who screened positive for OF and a randomly selected group of women who screened negative for OF were included in a nested case–control study (one case, four normal controls, and four incontinent controls) and underwent confirmatory clinical examinations. Main outcome measures: Clinically confirmed OF, and questionnaire sensitivity (Se) and specificity (Sp). Results: Of the 16 893 women who completed cross-sectional screening, 68 were screened-positive cases. Fifty-five (82%) screened-positive cases, 203 screened-negative normal controls, and 203 screened-incontinent controls participated in the case–control study, which confirmed one case of VVF and one case of both VVF and RVF without any false-negative cases. For VVF, the screening tool demonstrated Se 100% (95% CI 34.2–100.0%), Sp 86.9% (95% CI 83.3–89.9%), and estimated VVF prevalence as 12 per 100 000 (95% CI 3–43); for RVF, it demonstrated Se 100% (95% CI 20.7–100.0), Sp 99.8% (95% CI 98.6–100.0), and estimated RVF prevalence as 6 per 100 000 (95% CI 1–34). Conclusions: The OF screening questionnaire demonstrated high sensitivity and specificity in this low-prevalence setting. Tweetable abstract: Community-based obstetric fistula screening tool validation study, Nepal, n = 16 893: High Se, Sp & feasibility.