Diagnoses and mortality among prehospital emergency patients calling 112 with unclear problems: a population-based cohort study from Denmark

BACKGROUND: Patients calling for an emergency ambulance and assessed as presenting with 'unclear problem' account for a considerable part of all emergency calls. Previous studies have demonstrated that these patients are at increased risk for unfavourable outcomes. A deeper insight into the underlying diagnoses and outcomes is essential to improve prehospital treatment. We aimed to investigate which of these diagnoses contributed most to the total burden of diseases in terms of numbers of deaths together with 1- and 30-day mortality.

METHODS: A historic regional population-based observational cohort study from the years 2016 to 2018. Diagnoses were classified according to the World Health Organisation ICD-10 System (International Statistical Classification of Diseases and Related Health Problems, 10th edition). The ICD-10 chapters, R ('symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified)' and Z ('factors influencing health status and contact with health services") were combined and designated "non-specific diagnoses". Poisson regression with robust variance estimation was used to estimate proportions of mortality in percentages with 95% confidence intervals, crude and adjusted for age, sex and comorbidities.

RESULTS: Diagnoses were widespread among the ICD-10 chapters, and the most were 'non-specific diagnoses' (40.4%), 'circulatory diseases' (9.6%), 'injuries and poisonings' (9.4%) and 'respiratory diseases' (6.9%). The diagnoses contributing most to the total burden of deaths (n = 554) within 30 days were 'circulatory diseases' (n = 148, 26%) followed by 'non-specific diagnoses' (n = 88, 16%) 'respiratory diseases' (n = 85, 15%), 'infections' (n = 54, 10%) and 'digestive disease' (n = 39, 7%). Overall mortality was 2.3% (1-day) and 7.1% (30-days). The risk of mortality was highly associated with age.

CONCLUSION: This study found that almost half of the patients brought to the hospital after calling 112 with an 'unclear problem' were discharged with a 'non-specific diagnosis' which might seem trivial but should be explored more as these contributed the second-highest to the total number of deaths after 30 days only exceeded by 'circulatory diseases'.