Community-Acquired Respiratory Coinfection in Critically III Patients With Pandemic 2009 Influenza A(H1N1) Virus

Background: Little is known about the impact of community-acquired respiratory coinfection in patients with pandemic 2009 influenza A(H1N1) virus infection. Method: This was a prospective, observational, multicenter study conducted in 148 Spanish ICUs. Results: Severe respiratory syndrome was present in 645 ICU patients. Coinfection occurred in 113 (17.5%) of patients. Streptococcus pneumoniae (in 62 patients [54.8%]) was identified as the most prevalent bacteria. Patients with coinfection at ICU admission were older (47.5 +/- 15.7 vs 43.8 +/- 14.2 years, P < .05) and presented a higher APACHE (Acute Physiology and Chronic Health Evaluation) II score (16.1 +/- 7.3 vs 13.3 +/- 7.1, P < .05) and Sequential Organ Failure Assessment (SOFA) score (7.0 +/- 3.8 vs 5.2 +/- 3.5, P < .05). No differences in comorbidities were observed. Patients who had coinfection required vasopressors (63.7% vs 39.3%, P < .05) and invasive mechanical ventilation (69% vs 58.5%, P < .05) more frequently. ICU length of stay was 3 days longer in patients who had coinfection than in patients who did not (11 [interquartile range, 5-23] vs 8 [interquartile range 4-17], P = .01). Coinfection was associated with increased ICU mortality (26.2% vs 15.5%; OR, 1.94; 95% CI, 1.21-3.09), but Cox regression analysis adjusted by potential confounders did not confirm a significant association between coinfection and ICU mortality. Conclusions: During the 2009 pandemics, the role played by bacterial coinfection in bringing patients to the ICU was not clear, S pneumoniae being the most common pathogen. This work provides clear evidence that bacterial coinfection is a contributor to increased consumption of health resources by critical patients infected with the virus and is the virus that causes critical illness in the vast majority of eases. CHEST 2011; 139(3):555-562