Geographic isolation, rurality, and outcomes after critical illness: a retrospective cohort study of emergency admissions to critical care units in Scotland 2010-2021.

BACKGROUND The association between rurality, geographic isolation, and outcomes in critical care is complex, and important to the design and implementation of robust healthcare systems. We therefore conducted a retrospective cohort study of adult (≥16 yr) emergency admissions to critical care units in Scotland 2010-21. METHODS Data were linked across national inpatient records, the critical care database, and mortality records. Geographic isolation was determined by modelled travel time to the intensive care unit (ICU) and emergency department, and rurality by the national eight-fold Urban Rural Classification. Standardised admission rates were calculated, alongside survival analysis for all-cause mortality by isolation and rurality with ICU and hospital length of stay, and emergency hospital readmissions in the year after critical care admission. RESULTS A total of 50 914 first emergency admissions to the ICU over the study period were included in the analyses. Age-sex standardised admissions were 24.2% (95% confidence interval 19.4-28.2%) lower for areas ≥180 min from the ICU compared with areas <30 min from the ICU. No significant associations were demonstrated between mortality and any category of isolation. Greater mortality was demonstrated in other urban areas (settlements of 10 000 to 124 999 people) compared with large urban areas (settlements of ≥125 000 people) (adjusted hazard ratio 1.05, 95% confidence interval 1.01-1.08). CONCLUSIONS Admission rates to critical care were lower for patients in more isolated and more rural areas. Further research should explore the mechanisms for these findings and consider if strengthened access to critical care transfer and resource in remote areas might improve health outcomes.