Temporal trends across diagnostic subgroups of Dutch ICU patients over a decade; a nationwide cohort study.

BACKGROUND: The demand for intensive care in the Netherlands is influenced by evolving treatments, external factors such as pandemics, and policy decisions. Concerns have grown about Intensive Care Units (ICU) capacity, nurse shortages, and changing patient populations. Understanding temporal trends in ICU admissions and case-mix is essential for resource allocation and preparedness. METHODS: This descriptive study analyzed data from 2014 to 2023 from the National Intensive Care Evaluation registry. Patients were categorized using predefined diagnostic categories and age subgroups, alongside data-driven patient clusters identified through latent class analysis. Trends were analyzed in annual ICU admissions and average daily number of concurrent ICU patients. RESULTS: A total of 640,465 ICU admissions from 59 Dutch hospitals were included. Between 2014 and 2023, ICU admissions decreased by 15%. This decline was not linear: a modest downward trend before the pandemic followed by a more pronounced reduction during the pandemic period. The largest decrease was observed among patients aged ≥80 years (40%). In contrast, admissions for out-of-hospital cardiac arrest increased by 13%. Differing trends across diagnostic subgroups drove shifts in ICU case-mix, with an increasing relative contribution of younger and less severely ill patients, reflecting a changing ICU population. CONCLUSION: Changes in ICU case-mix occurred alongside declining admissions and occupancy between 2014 and 2023. These temporal patterns likely reflect both an underlying secular decline and additional pandemic-related effects. Ongoing monitoring of ICU population dynamics is essential for guiding capacity planning, optimizing workforce allocation, and strengthening preparedness for future public health challenges.