Mortality after paediatric emergency calls for patients with or without pre-existing comorbidity: a nationwide population based cohort study.

Background: Life-threatening conditions are infrequent in children. Current literature in paediatric prehospital research is centred around trauma and paediatric out-of-hospital cardiac arrests (POHCA). The aims of this study were to (1) outline the distribution of trauma, POHCA or other medical symptoms among survivors and non-survivors after paediatric emergency calls, and (2) to investigate these clinical presentations' association with mortality in children with and without pre-existing comorbidity, respectively.

Methods: Nationwide population-based cohort study including ground and helicopter emergency medical services in Denmark for six consecutive years (2016-2021). The study included all calls to the emergency number 1-1-2 regarding children ≤ 15 years (N = 121,230). Interhospital transfers were excluded, and 1,143 patients were lost to follow-up. Cox regressions were performed with trauma or medical symptoms as exposure and 7-day mortality as the outcome, stratified by 'Comorbidity', 'Severe chronic comorbidity' and 'None' based on previous healthcare visits.

Results: Mortality analysis included 76,956 unique patients (median age 5 (1-12) years). Annual all-cause mortality rate was 7 per 100,000 children ≤ 15 years. For non-survivors without any pre-existing comorbidity (n = 121), reasons for emergency calls were trauma 18.2%, POHCA 46.3% or other medical symptoms 28.9%, whereas the distribution among the 134 non-survivors with any comorbidity was 7.5%, 27.6% and 55.2%, respectively. Compared to trauma patients, age- and sex-adjusted hazard ratio for patients with calls regarding medical symptoms besides POHCA was 0.8 [0.4;1.3] for patients without comorbidity, 1.1 [0.5;2.2] for patients with comorbidity and 6.1 [0.8;44.7] for patients with severe chronic comorbidity.

Conclusion: In both non-survivors with and without comorbidity, a considerable proportion of emergency calls had been made because of various medical symptoms, not because of trauma or POHCA. This outline of diagnoses and mortality following paediatric emergency calls can be used for directing paediatric in-service training in emergency medical services.