Comparison of patient characteristics and long‐term mortality between transferred and non‐transferred COVID‐19 patients in Dutch intensive care units: A national cohort study

Abstract

Background: COVID-19 patients were often transferred to other intensive care units (ICUs) to prevent that ICUs would reach their maximum capacity. However, transferring ICU patients is not free of risk. We aim to compare the characteristics and outcomes of transferred versus non-transferred COVID-19 ICU patients in the Netherlands. Methods: We included adult COVID-19 patients admitted to Dutch ICUs between March 1, 2020 and July 1, 2021. We compared the patient characteristics and outcomes of non-transferred and transferred patients and used a Directed Acyclic Graph to identify potential confounders in the relationship between transfer and mortality. We used these confounders in a Cox regression model with left truncation at the day of transfer to analyze the effect of transfers on mortality during the 180 days after ICU admission. Results: We included 10,209 patients: 7395 non-transferred and 2814 (27.6%) transferred patients. In both groups, the median age was 64 years. Transferred patients were mostly ventilated at ICU admission (83.7% vs. 56.2%) and included a larger proportion of low-risk patients (70.3% vs. 66.5% with mortality risk <30%). After adjusting for age, APACHE IV mortality probability, BMI, mechanical ventilation, and vasoactive medication use, the hazard of mortality during the first 180 days was similar for transferred patients compared to non-transferred patients (HR [95% CI] = 0.99 [0.91-1.08]). Conclusions: Transferred COVID-19 patients are more often mechanically ventilated and are less severely ill compared to non-transferred patients. Furthermore, transferring critically ill COVID-19 patients in the Netherlands is not associated with mortality during the first 180 days after ICU admission.

Period of hospitalization and mortality in transferred versus non-transferred COVID-19 patients: Results from Germany

“…The separate analysis was necessary, as ICU patients were relatively more often transferred and at the same time showed a much higher mortality than non-ICU patients. The nding regarding mortality of transferred ICU patients is in line with the great majority of the previous studies on mortality in ICU patients performed in different countries at different periods of time [5,7,8,[11][12][13], suggesting the validity and comparability of our data. When focusing on the mortality of non-ICU patients, our results appear novel but compatible with the literature, as in a previous study [5] no higher mortality of transferred patients was observed, when pooling ICU and non-ICU patients after adjustment for several risk factors.…”

“…COVID-19 exerted considerable stress on medical capacity (e.g., hospital beds and medical staff [3,4], requiring a sophisticated patient management that included optimal allocation to the available hospital capacity and capability [5]. In Germany, as in other countries, this led to a high number of inter-hospital transfers [5][6][7][8][9], particularly regarding intensive care treatment, raising the question whether the transfers had an impact on patient outcomes.…”

“…The transfer of patients was guided by their individual characteristics and the capabilities of the hospitals involved but also undertaken preventively to restore capacities, especially regarding intensive care units (ICU). Several studies analyzed whether the transfer of ICU patients was linked to mortality [5,7,[11][12][13], with the common result that no adversely effect could be found, with one exception, mentioning even an improved survival for inter-regional transferred ICU patients compared to non-transferred patients during the rst COVID-19 wave in France [8]. In addition to mortality, the period of hospitalization is of major interest, as a longer stay may increase shortages of hospital beds, which was also implied by a study without the possibility of veri cation [8].…”

“…In addition to mortality, the period of hospitalization is of major interest, as a longer stay may increase shortages of hospital beds, which was also implied by a study without the possibility of veri cation [8]. A number of studies have addressed the period of hospitalization as secondary outcome [7,8,12] primarily in ICU patients, and only one of them included non-ICU patients [5]. Recently published data from Germany [6] demonstrated in great detail the rates and modes of transfer between hospitals of different levels of care in the rst wave of COVID-19.…”

Interhospital Transfer Versus Other Modes of Admission of Patients With Covid-19 at the University Hospital Andohatapenaka: “a Retrospective Cohort Study”

“…In a Dutch study, we compared the patient characteristics and long-term mortality of transferred and nontransferred COVID-19 patients in intensive care units. Transferred patients were more often mechanically ventilated but less severely ill than nontransferred patients [3]. The difference between this study and ours may be related to the type of transfer (clinical, capacity, repatriation) and the national crisis management policy of the 2 countries during COVID.…”