TOPLINE:

Primary care episodes of infectious intestinal disease among individuals in North-West London decreased from 2015 to 2024, whereas hospital admissions rose. The odds of disease-related hospital admissions were higher in children and adults aged 80 years or older during disease-related primary care episodes.

METHODOLOGY:

• Researchers used deidentified electronic records from a database covering 95% of general practice registrants in North-West London from January 2015 to December 2024 to assess trends in infectious intestinal disease-related primary care and hospital admission episodes among individuals with at least one primary care or hospital admission record with a related diagnostic code.
• Case definitions were listed as possible, probable, and confirmed infectious intestinal disease, indicating non-specific gastroenteritis symptoms, disease without a specified genus or species of gastrointestinal microorganism, and disease with a specified genus or species of gastrointestinal organism, respectively.
• Single infectious intestinal disease‑related primary care or hospital admission episodes applied a 21‑day window to group records, with 415,463 primary care episodes and 96,552 hospital admission episodes (55% female individuals in both).
• The disease‑related hospital admission during a primary care episode was defined as having a start date during the primary care episode; preceding or coinciding primary care activity was defined as an episode occurring 0-21 days before the start date of a hospital admission episode.
• Associations between hospital admissions and disease‑related primary care episodes or primary care activity 0-21 days before or concurrent with disease‑related admissions were assessed. The age at episode onset was noted, and the age group of 18-34 years was selected as the reference group.

TAKEAWAY:

• From 2015 to 2024, annual infectious intestinal disease-related primary care episodes declined from 51,009 to 40,450, whereas annual disease-related hospital admission episodes increased from 8732 to 10,356; both settings noted a dip in 2020 before rebounding.
• Among infectious intestinal disease-related primary care episodes, 1.6% were linked to a related hospital admission episode; the likelihood of disease-related hospital admissions was higher in children aged 0-4 years (adjusted odds ratio [aOR], 1.30; 95% CI, 1.19-1.42) and 5-11 years (aOR, 1.21; 95% CI, 1.10-1.34) than in individuals aged 18-34 years and markedly higher in individuals aged 80 years or older (aOR, 4.77; 95% CI, 4.36-5.22).
• Among disease-related hospital admissions, 5.8% had a related primary care episode 0-21 days prior; higher odds of a coinciding or preceding primary care episode were noted in children aged 0-4 years (aOR, 2.79; 95% CI, 2.53-3.08), followed by those aged 5-11 years (aOR, 2.09; 95% CI, 1.85-2.36) and 12-17 years (aOR, 1.68; 95% CI, 1.44-1.98), vs individuals aged 18-34 years.
• The odds of a coinciding or preceding disease-related primary care episode were lower among adults with a hospital admission episode­ — those aged 35-59 years (aOR, 0.72; 95% CI, 0.66-0.79) and 60-79 years (aOR, 0.82; 95% CI, 0.74-0.90) vs those aged 18-34 years. Patients from less deprived vs most deprived areas had higher odds of a linked primary care episode before or on admission.

IN PRACTICE:

"Our findings that older adults are both more likely than other age groups to have an IID [infectious intestinal disease]-related hospital admission following an IID-related primary care episode, and less likely than young children to have an IID-related primary care episode coinciding with or preceding an IID hospital admission episode, highlight the potential for strategies focusing on prevention, early identification and management of IID to avert severe disease and avoidable hospital admissions," the authors wrote.

SOURCE:

This study was led by Luke J. McGeoch, Health Protection Operations Division, UK Health Security Agency, London, England. It was published online on February 19, 2026, in BJGP Open.

LIMITATIONS:

The non‑specific primary care coding and the inclusion of possible and probable entries may have led to the misclassification of episodes that were not true infectious intestinal disease. Many linked primary care and hospital admission episodes shared the same start date, thereby suggesting retrospective coding from hospital records. Emergency department attendances were not included, and the severity and outcomes of disease-related episodes were not captured.

DISCLOSURES:

Two authors reported receiving support from the National Institute for Health and Care Research Applied Research Collaboration North-West London, which also covered the data access costs. The authors reported having no competing interests.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.