New study determines factors that can send flu patients to the ICU

Numerous independent factors – including a history of obstructive/central sleep apnea syndrome (OSAS/CSAS) or myocardial infarction, along with a body mass index greater than 30 g/m²– could be related to ICU admission and subsequent high mortality rates in influenza patients, according to an analysis of patients in the Netherlands who were treated during the influenza epidemic of 2015-2016.

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Along with determining these factors, lead author M.C. Beumer, of Radboud University Medical Center, the Netherlands, and his coauthors found that “coinfections with bacterial, fungal, and viral pathogens developed more often in patients who were admitted to the ICU.” The study was published in the Journal of Critical Care.

The coauthors reviewed 199 influenza patients who were admitted to two medical centers in the Netherlands during October 2015–April 2016. Of those patients, 45 (23%) were admitted to the ICU, primarily because of respiratory failure, and their mortality rate was 17/45 (38%) versus an overall mortality rate of 18/199 (9%).

Compared with patients in the normal ward, patients admitted to the ICU more frequently had a history of OSAS/CSAS (11% vs. 3%; P = .03) and MI (20% vs. 6%; P = .007), along with a BMI higher than 30 g/m² (30% vs. 15%; P = .04) and dyspnea as a symptom (77% vs. 48%,; P = .001). In addition, more ICU-admitted patients had influenza A rather than influenza B, compared with those not admitted (87% vs. 66%; P = .009).

Pulmonary coinfections – including bacterial, fungal, and viral pathogens – were also proportionally higher among the 45 ICU patients (56% vs. 20%; P less than .0001). The most common bacterial pathogens were Staphylococcus aureus (11%) and Streptococcus pneumoniae (7%) while Aspergillus fumigatus (18%) and Pneumocystis jirovecii (7%) topped the fungal pathogens.

Mr. Beumer and his colleagues noted potential limitations of their work, including the selection of patients from among the “most severely ill” contributing to an ICU admission rate that surpassed the 5%-10% described elsewhere. They also admitted that their study relied on a “relatively small sample size,” focusing on one seasonal influenza outbreak. However, “despite the limited validity,” they reiterated that “the identified factors may contribute to a complicated disease course and could represent a tool for early recognition of the influenza patients at risk for a complicated disease course.”

The authors reported no conflicts of interest.

SOURCE: Beumer MC et al. J Crit Care. 2019;50:59-65.