Background: Multiple case definitions for post-diarrheal hemolytic uremic syndrome (D+ HUS) associated with Shiga toxin-producing Escherichia coli (STEC) are used across public health, research, and clinical practice. Methods: To identify a single definition of D+ HUS for standardized use, we evaluated the comparability and validity of four common, heterogeneous definitions: the Council of State and Territorial Epidemiologists (CSTE) definition, hematology-focused and age-focused definitions from the literature, and hospital diagnosis. We reviewed medical records from 471 hospitalized E. coli O157:H7 cases reported in Washington State, 2005–2014. We assessed 1) reliability across definitions, 2) comparability of temporal trends, and 3) sensitivity and specificity using an omnibus reference standard, developed using a combination of definition agreement and clinical outcomes. With the standard, we classified cases as definite, borderline, or unlikely/not post-diarrheal D+ HUS. Results: Reliability was highest between the age-focused definition and hospital diagnosis (κ = 0.84), and temporal trends were largely comparable across definitions. For definite D+ HUS cases, the age-focused definition had the highest overall validity [100% sensitivity, 95% confidence interval (CI): 94%, 100%; 96% specificity, 95% CI: 94%, 98%]. The CSTE definition had low specificity (75%, 95% CI: 70%, 79%). Conclusions: In this review, the CSTE definition overestimated the burden of D+ HUS, and the age-focused definition provided the best overall reliability and validity to define post-diarrheal D+ HUS. Disease monitoring and research activities should consider using the age-focused D+ HUS definition.
Bibliographical noteFunding Information:
This work was supported by the National Institute of Allergy and Infectious Diseases, National Institutes of Health, United States [ F31AI126834 ]; the National Institute of Environmental Health Sciences, National Institutes of Health, United States [ T32ES015459 ]; and the Washington University Digestive Diseases Research Core Center, United States [ 5P30 DK052574 ]. The funding bodies had no role in the design, data collection, analysis, or interpretation of the study. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
- E. coli O157:H7
- Hemolytic uremic syndrome
- Shiga toxin-producing Escherichia coli