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

BACKGROUND: 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. OBJECTIVES: We aimed to assess changes in inpatient pathogen-specific documentation rates and clinical outcomes on a national level. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.