Degree of adherence to recommended antiviral treatment during the pandemic and post-pandemic periods of influenza A(H1N1)pdm09 in 148 intensive care units in Spain.

Objective: To determine the degree of antiviral treatment recommendations adherence and its impact to critical ill patients affected by influenza A(H1N1)pdm09 mortality.

Design: Secondary analysis of prospective study.

Setting: Intensive care (UCI).

Patients: Patients with influenza A(H1N1)pdm09 in the 2009 pandemic and 2010-11 post-Pandemic periods.

Variables: Adherence to recommendations was classified as: Total (AT); partial in doses (PD); partial in time (PT), and non-adherence (NA). Viral pneumonia, obesity and mechanical ventilation were considered severity criteria for the administration of high antiviral dose. The analysis was performed using t-test or «chi» square. Survival analysis was performed and adjusted by Cox regression analysis.

Results: A total of 1,058 patients, 661 (62.5%) included in the pandemic and 397 (37.5%) in post-pandemic period respectively. Global adherence was achieved in 41.6% (43.9% and 38.0%; P=.07 respectively). Severity criteria were similar in both periods (68.5% vs. 62.8%; P=.06). The AT was 54.7% in pandemic and 36.4% in post-pandemic period respectively (P<.01). The NA (19.7% vs. 11.3%; P<.05) and PT (20.8% vs. 9.9%, P<.01) was more frequent in the post-pandemic period. The mortality rate was higher in the post-pandemic period (30% vs. 21.8%, P<.001). APACHE II (HR=1.09) and hematologic disease (HR=2.2) were associated with a higher mortality and adherence (HR=0.47) was a protective factor.

Conclusions: A low degree of adherence to the antiviral treatment was observed in both periods. Adherence to antiviral treatment recommendations was associated with lower mortality rates and should be recommended in critically ill patients with suspected influenza A(H1N1)pdm09.