Incidence, Etiology, and Severity of Acute Gastroenteritis Among Prospectively Enrolled Patients in 4 Veterans Affairs Hospitals and Outpatient Centers, 2016-2018

Abstract

Background: Acute gastroenteritis (AGE) burden, etiology, and severity in adults is not well characterized. We implemented a multisite AGE surveillance platform in 4 Veterans Affairs Medical Centers (Atlanta, Georgia; Bronx, New York; Houston, Texas; and Los Angeles, California), collectively serving >320 000 patients annually.

Methods: From 1 July 2016 to 30 June 2018, we actively identified inpatient AGE case patients and non-AGE inpatient controls through prospective screening of admitted patients and passively identified outpatients with AGE through stool samples submitted for clinical diagnostics. We abstracted medical charts and tested stool samples for 22 pathogens by means of multiplex gastrointestinal polymerase chain reaction panel followed by genotyping of norovirus- and rotavirus-positive samples. We determined pathogen-specific prevalence, incidence, and modified Vesikari severity scores.

Results: We enrolled 724 inpatients with AGE, 394 non-AGE inpatient controls, and 506 outpatients with AGE. Clostridioides difficile and norovirus were most frequently detected among inpatients (for AGE case patients vs controls: C. difficile, 18.8% vs 8.4%; norovirus, 5.1% vs 1.5%; P < .01 for both) and outpatients (norovirus, 10.7%; C. difficile, 10.5%). The incidence per 100 000 population was highest among outpatients (AGE, 2715; C. difficile, 285; norovirus, 291) and inpatients ≥65 years old (AGE, 459; C. difficile, 91; norovirus, 26). Clinical severity scores were highest for inpatient norovirus, rotavirus, and Shigella/enteroinvasive Escherichia coli cases. Overall, 12% of inpatients with AGE had intensive care unit stays, and 2% died; 3 deaths were associated with C. difficile and 1 with norovirus. C. difficile and norovirus were detected year-round with a fall/winter predominance.

Conclusions: C. difficile and norovirus were leading AGE pathogens in outpatient and hospitalized US veterans, resulting in severe disease. Clinicians should remain vigilant for bacterial and viral causes of AGE year-round.

Conflict of interest statement

Potential conflicts of interest.

V. C. M. reports grants from Gilead, ViiV, and Bayer, and personal fees from Lilly, Gilead, and ViiV, outside the submitted work. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.

Published by Oxford University Press for the Infectious Diseases Society of America 2020.

Figures

Figure 1.

Screening, enrollment and study completion for inpatients with acute gastroenteritis (AGE), inpatient controls, and outpatients with AGE, from July 2016 to June 2018.

Figure 2.

Prevalence of pathogens detected by means of the BioFire FilmArray Gastrointestinal Panel, from July 2016 to June 2018. A, Inpatients with acute gastroenteritis (AGE) and non-AGE inpatient controls. *Significant difference (P < .05; χ2 test) in prevalence between case patients and controls for the following pathogens: Clostridioides difficile (P < .001), norovirus (P = .003), Campylobacter spp. (P < .001), Shigella/enteroinvasive Escherichia coli (EIEC) (P = .003), Salmonella (P = .03), and rotavirus (P = .01). The following pathogens are on the FilmArray panel but are not included because there were no positive detections: Vibrio cholerae, Escherichia coli O157, Aeromonas, and Cyclospora cayetanensis. Two stool specimens from inpatient controls were excluded owing to inconclusive results. B, Outpatients with AGE. The following pathogens on the FilmArray panel are not included because there were no positive detections: Entamoeba histolytica, Plesiomonas shigelloides, V. cholerae, E. coli O157, and Aeromonas. Two outpatient stool specimens were excluded owing to inconclusive results. Abbreviations: EAEC, enteroaggregative Escherichia coli; EPEC, enteropathogenic Escherichia coli; ETEC, enterotoxigenic Escherichia coli; G. lamblia, Giardia lamblia; STEC, Shiga-like toxin-producing Escherichia coli; Y. enterocolitica, Yersinia enterocolitica.

Figure 3.

Seasonality of viral and bacterial pathogens among inpatient and outpatient cases, from July 2016 to June 2018. A, Viral pathogens. B, Bacterial pathogens. Abbreviations: C. difficile, Clostridioides difficile; EIEC, enteroinvasive Escherichia coli.

Figure 4.

Genotypes for norovirus (n = 71) and rotavirus (n = 19).