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, Bronx, Houston and Los Angeles), collectively serving >320,000 patients annually. Methods From July 1, 2016–June 30, 2018, we actively identified AGE inpatient cases and non-AGE inpatient controls through prospective screening of admitted patients and passively identified outpatient cases through stool samples submitted for clinical diagnostics. We abstracted medical charts and tested stool samples for 22 pathogens via multiplex gastrointestinal PCR 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 inpatient cases, 394 controls, and 506 outpatient cases. Clostridioides difficile and norovirus were most frequently detected among inpatients (cases vs controls: C. difficile, 18.8% vs 8.4%; norovirus, 5.1% vs 1.5%; p<0.01 for both) and outpatients (norovirus: 10.7%; C. difficile: 10.5%). 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/EIEC cases. Overall, 12% of AGE inpatient cases had ICU 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.

COVID-19–Related Hospitalization Rates and Severe Outcomes Among Veterans From 5 Veterans Affairs Medical Centers: Hospital-Based Surveillance Study

“…First, early during the pandemic, limited COVID-19 testing was conducted nationwide, and this may have led to an under-ascertainment of patients with COVID-19. Second, although prior studies have indicated that 91% of veterans enrolled in VA healthcare in these 5 site catchment areas use their local VAMCs for care [ 5 ], veterans hospitalized elsewhere would not have been captured in our surveillance, thereby resulting in underestimation of hospitalization rates. Third, as the number of cases in younger age groups was much smaller than in older adults, we were not able to calculate relative statistics for severe clinical outcomes in veterans aged 18-49 years.…”

“…To identify eligible patients for COVID-19 surveillance, trained research personnel screened admission logs and diagnoses [ 5 ], lists of patients being tested for COVID-19, and the results from respiratory specimens submitted for testing. Patients were eligible for inclusion in this study if they were admitted to the VAMC and had a positive molecular test for SARS-CoV-2 within 14 days prior to admission or during hospitalization.…”

“…These US veterans constitute a population that is older, is predominantly male, has a high rate of chronic medical conditions, and has a higher representation from certain racial and ethnic groups compared with the general population. We built a COVID-19 surveillance system on the infrastructure of SUPERNOVA (Surveillance Platform for Enteric and Respiratory Infectious Organisms in the Veterans Affairs population), a population-based platform that captures information on cases of veterans with acute gastroenteritis and acute respiratory illness [ 5 ] from 5 VA Medical Centers (VAMCs) located in Atlanta, Georgia; Bronx, New York; Houston, Texas; Los Angeles, California; and Palo Alto, California. This surveillance system helps understand the epidemiology, hospitalization rates, and underlying medical conditions among these US veterans.…”

Association of Secretor Status and Recent Norovirus Infection With Gut Microbiome Diversity Metrics in a Veterans Affairs Population

“…Recruitment into the SUPERNOVA study has been described elsewhere [ 22 ]. In brief, individuals were enrolled as cases in the SUPERNOVA study if they met the definition for AGE ( Supplementary Methods ) when presenting as outpatients or when hospitalized at participating VAMCs (Atlanta, Houston, Bronx, and Los Angeles).…”

Adapting the Surveillance Platform for Enteric and Respiratory Infectious Organisms at United States Veterans Affairs Medical Centers (SUPERNOVA) for COVID-19 Among Hospitalized Adults: Surveillance Protocol

“…Acute respiratory illness surveillance with laboratory confirmation began as a pilot at one site (Houston) in 2016, with a second site (Los Angeles) added in 2017. Acute respiratory illness surveillance included: (1) identification of patients who had been admitted with a diagnosis consistent with acute respiratory illness and/or had received clinician-ordered viral respiratory diagnostic testing; (2) medical record reviews and chart abstractions to obtain demographic and clinical information including clinical course; and (3) collection of residual respiratory and serum specimens (18). By 2019-2020, surveillance for acute gastroenteritis and acute respiratory illness was including ∼900 and ∼1,600 patients, respectively.…”