Saturday, July 28, 2012

Treatment with neuraminidase inhibitors for critically ill patients with influenza A(H1N1)pdm09

Backgound. Neuraminidase inhibitor (NAI) antiviral drugs can shorten the duration of uncomplicated influenza illness when administered early (<48 hours after illness onset) to otherwise healthy outpatients, but the optimal timing of effective therapy for critically-ill patients is not well established.

We analyzed California surveillance data to characterize the outcomes of patients in intensive care units (ICU) treated with NAIs for influenza A(H1N1)pdm09 [pH1N1]. Demographic and clinical data were abstracted from medical records using standardized case report forms.

From April 3, 2009 – August 10, 2010, 1950 pH1N1 cases hospitalized in ICUs were reported. Of 1859 (95%) with information available, 1676 (90%) received NAI treatment and 183 (10%) did not. The median age was 37 years (range: 1 week - 93 years), 1473 (79%) had ≥1 co-morbidity, and 492 (26%) died. The median time from symptom onset to starting NAI treatment was 4 days (range 0-52). NAI treatment was associated with survival: 107 of 183 (58%) untreated cases survived, compared to 1260 of 1676 (75%) treated cases (p≤.0001). There was a trend towards improved survival for those treated earliest (p <.0001). Treatment initiated within 5 days after symptom onset was associated with improved survival compared to those never treated (p<0.05).

NAI treatment of critically ill pH1N1 patients improves survival. While earlier treatment conveyed the most benefit, patients started on treatment up to 5 days from symptom onset also had increased survival. Further research is needed on whether starting NAI treatment later than 5 days may also convey benefit.

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