Outcomes Following Acute Pulmonary Embolism in an Irish Population of over 1 Million Individuals: Opportunities for Quality Improvement and More Effective Resource Utilisation
Authors: Tierney Alexandra , Ni Ainle Fionnuala , Lyons Declan , Edebiri Osasere , Saeed Khalid , Kelliher Sarah , Saif Kiran , Faryal Rehman , Maung Su Wai , Johnson Howard , Fitzpatrick Michael , O' Doherty Roseann , Coll Jillian , Mohamed Sara , Ali Mohamed , Bannon Noirin , O'Neill Annemarie , Breslin Tomas , Murphy Karen , Kevane Barry 
Published: November 2021

Abstract
Introduction
Pulmonary embolism (PE) is a leading cause of cardiovascular morbidity worldwide. The risk of early death in the setting of untreated PE may be as high as 30%. However, diagnostic and therapeutic advances in recent years have led to a progressive decline in global PE-related mortality and recent data describing rates of in-hospital death following PE suggest a mortality rate of approximately 5-15%. Moreover, strategies directed at stratification of PE severity have been shown to safely identify a sub-group of low-risk patients (up to 30-50% of all patients) for whom outpatient management is feasible without the need for hospital admission. Avoiding hospitalisation for low-risk PE patients is associated with improved patient satisfaction and avoids exposing patients to the risks associated with hospital admission. Ambulatory PE management would also be predicted to lead to significant healthcare cost-savings. However ambulatory care models for low-risk PE appear to be under-utilised despite these potential benefits. Barriers to implementation include access to outpatient follow-up services and the perceived risks associated with this model of care.
The Ireland East Hospital Group (IEHG) is the largest hospital network in the Republic of Ireland, consisting of 11 hospitals (including large academic centres, community general hospitals and the national maternity hospital). The IEHG serves a population of over 1.1 million individuals. We sought to determine the frequency of admissions to hospital with PE and to assess key outcomes, including length-of-stay (LOS) and in-hospital mortality within this population.
Methods
Data pertaining to PE diagnosis from January 2018 to December 2020 were obtained from NQAIS Clinical (National Quality Assessment and Improvement System; an electronic reporting tool which is populated with anonymised data extracted from the hospital in-patient enquiry system). This system compiles diagnostic data on all patients by ICD-10 code at the time of discharge. For the purposes of this analysis the ICD-10 codes I26.0 and I26.9 were used to identify patients with PE and only admission episodes where PE was the primary diagnosis were included; cases of 'secondary PE' (historical PE or hospital-acquired) were excluded. Projected population figures, extrapolated from Census 2016 data, were obtained from Health Atlas Ireland (an open-source application providing access to datasets developed by the Health Intelligence Unit of the Health Service Executive of Ireland).
Results
During the 3-year study period, 958 in-patient episodes occurred where PE was recorded as the primary diagnosis, corresponding to an incidence of 0.37 per 1000 adults per annum (95% CI 0.35 to 0.40). The incidence was highest in the over 85 years age-group (1.07 per 1000 per annum; 95% CI 0.80 to 1.33). PE was more common in women in all age-groups apart from the 46-65 years age group [males: 0.51 (95% CI 0.44-0.51) vs females: 0.36 (95% CI 0.3-0.42) per 1000].
In 82.7% of episodes, the ultimate discharge destination was to home. In 5.3% the discharge destination was a nursing home and 4.6% were transferred to another hospital. The all-cause in-hospital mortality rate was 3.1% (30 fatalities; 18 females, 12 males). Most deaths occurred in the 66-85 years age-group (n=14), with 9 fatalities in the age &gt;85 years group and 7 fatal PE events in the 46-65 years age-group.
Average hospital LOS was 7.8 days. 8.9% of inpatient episodes resulted in same-day discharge. In 55.9% of episodes, discharge occurred after day 4. Those discharged to home had an average length of stay of 6.31 days, while patients awaiting nursing home facilities averaged 26.5 days.
Conclusion
The incidence of acute presentation with PE within this population is consistent with international reports. The rate of in-hospital mortality compares favourably with these international standards. The mortality rate may reflect improvements in PE care but may also reflect the inclusion of a significant number of 'low-risk' individuals in the analysis (many of whom may have been suitable for outpatient management). The mortality rate might also reflect increased detection of small, low-risk distal PE (as a result of advances in diagnostics). In any event, these data suggest that more widespread implementation of outpatient PE management is likely to be feasible and would represent an opportunity for improved resource utilisation.

Disclosures
Ni Ainle: Leo Pharma: Research Funding; Actelion: Research Funding; Daiichi-Sankyo: Research Funding; Bayer Pharma: Research Funding. Kevane: Leo Pharma: Research Funding.