National trends in pathogen-specific diagnoses and outcomes among hospitalizations for infectious diarrhea

The diagnostic evaluation of infectious diarrhea has evolved with increasing adoption of multiplex gastrointestinal nucleic acid amplification tests and changing diagnostic strategies for Clostridioides difficile.

We aimed to assess changes in inpatient pathogen-specific documentation rates and clinical outcomes on a national level.

We performed a retrospective cross-sectional study using the National Inpatient Sample from 2016 to 2023. Adult hospitalizations with a primary diagnosis of presumed infectious diarrhea were identified using ICD-10 codes. Temporal trends in pathogen-specific documentation were evaluated. Multivariable regression models were used to identify factors associated with pathogen-specific documentation and evaluate associations with clinical outcomes.

A total of 1,174,500 hospitalizations for presumed infectious diarrhea were identified, of which 710,335 (60.5%) had a specified pathogen. Pathogen specification rates remained stable from 2016 to 2023 (minimum of 59.6% in 2019 to the maximum of 62.1% in 2023; OR per year 1.00, 95% CI: 1.00-1.01, p = .282). Clostridioides difficile declined over time, accounting for 53.7% of infectious diarrhea hospitalizations in 2016 compared to 41.2% in 2023 (OR per year 0.94, p < .001). In contrast, norovirus and Campylobacter jejuni increased during the study period. Older age and higher comorbidity burden were independently associated with increased pathogen-specific documentation. Pathogen-specific documentation was associated with increased mortality (aOR 3.15, 95% CI: 2.73-3.63). These associations were substantially attenuated after exclusion of Clostridioides difficile.

Pathogen-specific documentation rates among hospitalizations for presumed infectious diarrhea remained stable nationally from 2016 to 2023, although identification of non-Clostridioides difficile infections appeared to increase.