Undocumented migrants in French intensive care units in 2011-2018: retrospective nationwide study

Whether undocumented migrants admitted to intensive care units (ICUs) have specific features is unknown. We aimed to determine the features and outcomes of undocumented migrants admitted to French ICUs.

We retrospectively included all undocumented adult migrants admitted in 2011-2018 and compared them to the general ICU population. We also compared these two groups matched on age, sex, severity, comorbidities, reason for ICU admission and public/private hospital.

We identified 14,554 ICU stays, with an increase from 2 to 4‰ of all ICU admissions over time. Shock (16.7%), post-operative care (13.8%), and trauma (10.5%) were the main reasons for ICU admission. Compared to general ICU patients, migrants were younger and had greater disease severity. After adjustment on age and sex, the following were more common in migrants: shock (OR 1.2 [1.14-1.25]; P < 0.0001), infections (1.48 [1.38-1.54]; P < 0.001), acute respiratory failure (1.09 [1.03-1.15]; P = 0.006), acute kidney injury (1.12 [1.05-1.19]; P < 0.001), obstetric events (1.53 [1.66-1.81]; P < 0.0001), and neurological deficits (1.19 [1.12-1.27]; P < 0.0001). In the matched study, migrants more often required vasopressors, mechanical ventilation, and renal replacement therapy; had longer ICU stays (median 4 [2-8] vs. 4 [2-7] days; P < 0.0001) and hospital stays (10 [5-20] vs. 8 [4-15]; P < 0.0001) and had higher hospital costs (14.2 ± 23.6 vs. 13.4 ± 11.5 K€; P < 0.0001). Hospital mortality was similar (6.7% vs. 6.6%; P = 0.69).

Admissions of undocumented migrants to French ICUs doubled from 2011 to 2018. The patients were younger and, although sicker, achieved similar outcomes to those in general ICU patients.