Impact of ICU transfers on the mortality rate of patients with COVID-19: insights from comprehensive national database in France

Abstract

Background The first wave of the COVID-19 pandemic confronted healthcare systems around the world with unprecedented organizational challenges, particularly regarding the availability of intensive care unit (ICU) beds. One strategy implemented in France to alleviate healthcare pressure during the first COVID-19 wave was inter-hospital transfers of selected ICU patients from overwhelmed areas towards less saturated ones. At the time, the impact of this transfer strategy on patient mortality was unknown. We aimed to compare in-hospital mortality rates among ICU patients with COVID-19 who were transferred to another healthcare facility and those who remained in the hospital where they were initially admitted to. Method A prospective observational study was performed from 1 March to 21 June 2020. Data regarding hospitalized patients with COVID-19 were collected from the Ministry of Health-affiliated national SI-VIC registry. The primary endpoint was in-hospital mortality. Results In total, 93,351 hospital admissions of COVID-19 patients were registered, of which 18,348 (19.6%) were ICU admissions. Transferred patients (n = 2228) had a lower mortality rate than their non-transferred counterparts (n = 15,303), and the risk decreased with increasing transfer distance (odds ratio (OR) 0.7, 95% CI: 0.6–0.9, p = 0.001 for transfers between 10 and 50 km, and OR 0.3, 95% CI: 0.2–0.4, p < 0.0001 for transfer distance > 200 km). Mortality decreased overall over the 3-month study period. Conclusions Our study shows that the mortality rates were lower for patients with severe COVID-19 who were transferred between ICUs across regions, or internationally, during the first pandemic wave in France. However, the global mortality rate declined overall during the study. Transferring selected patients with COVID-19 from overwhelmed regions to areas with greater capacity may have improved patient access to ICU care, without compounding the short-term mortality risk of transferred patients.

Major interregional differences in France of COVID-19 hospitalization and mortality from January to June 2020

“…They did not consider the DROM departments, which experienced a much different epidemic dynamic compared to mainland France, as shown in the present study. Furthermore, due to the real-time functioning of the SI-VIC database [28] , there were few retrospective corrections (e.g., adding missing cases having occurred prior to March). By contrast, in the PMSI database each hospital was asked to retrospectively review possible COVID cases and to add the appropriate CIM-10 identification codes.…”

Intensive care unit-to-unit capacity transfers are associated with increased mortality: no hasty conclusions in the event of a crisis

“…As the authors notice, the main result is somewhat surprising as higher mortality has not been reported in recent literature [ 2 , 3 ]. Reasons could be explained as follow: first, the authors specify that 20% of capacity transfers occurred at night, involving severe critically ill patients with acute lung injury, sepsis, and cardiogenic shock.…”

“…Assuming that interhospital transfers are unsafe and choosing a strategy of implementation of new ICU beds to face surge of critically ill patients could lead to a higher mortality [ 7 ]. During the first months of the COVID-19 crisis, countries planned and organized large-scale interhospital transfers either for clinical or capacity reasons and demonstrated that transferred patients did not have a higher mortality rate [ 2 , 3 , 8 ]. However, we agree with the authors and acknowledge that “understanding the impact of ICU-to-ICU transfer on patient outcome is complex and must consider a couple of important aspects” such as identifying appropriate control patients.…”

The association of intensive care capacity transfers with survival in COVID-19 patients from a Scottish district general hospital: A retrospective cohort study

“… 18 Another study of a national French database suggests that mortality in transferred patients is lower, albeit with no standardisation of patient baseline characteristics. 19 When corrected for comorbidities and disease severity, a cross-sectional study of all public and private hospitals in France still found lower intensive care unit mortality in patients that underwent inter-regional transfer. 20 Aside from the French data, there is early evidence from a retrospective review in the United States that critical care transport was associated with few adverse events and similar mortality to patients in other COVID-19 studies.…”