Non-conveyance of older adult patients and association with subsequent clinical and adverse events after initial assessment by ambulance clinicians : A cohort analysis

BACKGROUND: Older adults (age ≥ 65 years) represent a significant proportion of all patients who are not transported to hospital after assessment by ambulance clinicians (non-conveyed patients). This study aimed to fill the knowledge gap in the understanding of the prevalence of older adult non-conveyed patients and investigate their characteristics and risk factors for subsequent and adverse events with those of younger non-conveyed patients comparatively. METHODS: This population-based retrospective cohort study included all adult non-conveyed patients who availed the ambulance service of Region Stockholm, Sweden in 2015; they were age-stratified into two groups: 18-64 and ≥ 65 years. Inter-group differences in short-term outcomes (i.e. emergency department visits, hospitalisations, and mortality within 7 days following non-conveyance) were assessed using multivariate regression analyses. RESULTS: Older adult patients comprised 48% of the 17,809 non-conveyed patients. Dispatch priority levels were generally lower among older non-conveyed patients than among younger patients. Non-conveyance among older patients occurred more often during daytime, and they were more frequently assessed by ambulance clinicians with nonspecific presenting symptoms. Approximately one in five older adults was hospitalised within 7 days following non-conveyance. Patients presenting with infectious symptoms had the highest mortality risk following non-conveyance. Oxygen saturation level < 95% or systolic blood pressure > 160 mmHg had significantly higher associations with hospitalisation within 7 days following non-conveyance in older adult patients. CONCLUSIONS: Older adult patients have an increased risk for adverse events following non-conveyance. In combination with a complex and variating presentation of symptoms and vital signs proved difficult for dispatch operators and ambulance clinicians to identify and assess, the identified risks raise questions on the patient safety of older adult non-conveyed patients. The results indicate a system failure that need to be managed within the ambulance service organisation to achieve higher levels of patient safety for older non-conveyed patients