Defining Diarrhea: A Population-Based Validation Study of Caregiver-Reported Stool Consistency in the Amhara Region of Ethiopia

• Type of Material: Article
• Authors: Kristen Aiennjoy, University of California San Francisco; Solomon Aragie, Carter Center Ethiopia; Sintayehu Gebresillasie, Carter Center Ethiopia; Dionna M. Fry, University of California San Francisco; Adane Dagnew, Carter Center Ethiopia; Dagnachew Hailu, Carter Center Ethiopia; Melsew Chanyalew, Amhara Regional Health Bureau; Zerihun Tadesse, Carter Center Ethiopia; Aisha Stewart, Carter Center; Kelly Callahan, Carter Center; Matthew Freeman, Emory University; John Neuhaus, University of California San Francisco; Benjamin F. Arnold, University of California Berkeley; Jeremy D. Keenan, University of California San Francisco
• Language: English
• Date: 2018-01-01
• Publisher: American Society of Tropical Medicine and Hygiene
• Publication Version: Final Published Version
• Copyright Statement: © 2018 by The American Society of Tropical Medicine and Hygiene.
• Final Published Version (URL): http://dx.doi.org/10.4269/ajtmh.17-0806
• Title of Journal or Parent Work: American Journal of Tropical Medicine and Hygiene
• ISSN: 0002-9637
• Volume: 98
• Issue: 4
• Start Page: 1013
• End Page: 1020
• Grant/Funding Information: This study was supported by the National Institute of Health (NEI U10 EY016214), (NICHD F31 HD088070-01A1 [to K. A.]), and (NIAID 1K01AI119180 [to B. F. A.]); That Man May See and The Sara & Evan Williams Foundation; and Research to Prevent Blindness.
• Keywords: IRRITABLE-BOWEL-SYNDROME; DISEASES; TRANSIT-TIME; Public, Environmental & Occupational Health; Science & Technology; CHILDREN; MIDDLE-INCOME SETTINGS; SANITATION; FORM SCALE; WATER; SPECIFICITY; DIAGNOSTIC-TEST; Tropical Medicine; Life Sciences & Biomedicine
• Research Categories: Health Sciences, Epidemiology; Biology, Biostatistics; Health Sciences, Public Health

Abstract

Diarrhea is a leading cause of death among children aged less than five years globally. Most studies of pediatric diarrhea rely on caregiver-reported stool consistency and frequency to define the disease. Research on the validity of caregiver-reported diarrhea is sparse. We collected stool samples from 2,398 children participating in two clinical trials in the Amhara region of Ethiopia. The consistency of each stool sample was graded by the child's caregiver and two trained laboratory technicians according to an illustrated stool consistency scale. We assessed the reliability of graded stool consistency among the technicians, and then compared the caregiver's grade with the technician's grade. We also tested if the illustrated stool consistency scale could improve the validity of caregiver's report. The weighted kappa measuring the agreement between the two laboratory technicians reached 0.90 after 500 stool samples were graded. The sensitivity of caregiver-reported loose or watery stool was 15.5% (95% confidence interval [CI]: 9.7, 24.2) and the specificity was 98.4% (95% CI 97.1, 99.1). With the illustrated scale, the sensitivity was 68.5% (95% CI: 58.5, 77.1) and the specificity was 86.1% (95% CI: 79.3, 90.9). The results indicate that caregiver-reported stool consistency using the terms "loose or watery" does not accurately describe stool consistency as graded by trained laboratory technicians. Given the predominance of using caregiver-reported stool consistency to define diarrheal disease, the low sensitivity identified in this study suggests that the burden of diarrheal disease maybe underestimated and intervention effects could be biased. The illustrated scale is a potential low-lost tool to improve the validity of caregiver-reported stool consistency.