Delay in diagnosis of influenza A (H1N1)pdm09 virus infection in critically ill patients and impact on clinical outcome.

Francisco Álvarez-Lerma,On Behalf Of The H1N1 Getgag/Semicyuc Study Group ,Francisco Javier González De Molina,Clara Vila,Ignacio Martín Loeches,Sandra Barbadillo,Joan Ramón Masclans,Alejandro Rodríguez,Judith Marín-Corral

doi:10.1186/s13054-016-1512-1

Abstract

BackgroundPatients infected with influenza A (H1N1)pdm09 virus requiring admission to the ICU remain an important source of mortality during the influenza season. The objective of the study was to assess the impact of a delay in diagnosis of community-acquired influenza A (H1N1)pdm09 virus infection on clinical outcome in critically ill patients admitted to the ICU.MethodsA prospective multicenter observational cohort study was based on data from the GETGAG/SEMICYUC registry (2009–2015) collected by 148 Spanish ICUs. All patients admitted to the ICU in which diagnosis of influenza A (H1N1)pdm09 virus infection had been established within the first week of hospitalization were included. Patients were classified into two groups according to the time at which the diagnosis was made: early (within the first 2 days of hospital admission) and late (between the 3rd and 7th day of hospital admission). Factors associated with a delay in diagnosis were assessed by logistic regression analysis.ResultsIn 2059 ICU patients diagnosed with influenza A (H1N1)pdm09 virus infection within the first 7 days of hospitalization, the diagnosis was established early in 1314 (63.8 %) patients and late in the remaining 745 (36.2 %). Independent variables related to a late diagnosis were: age (odds ratio (OR) = 1.02, 95 % confidence interval (CI) 1.01–1.03, P < 0.001); first seasonal period (2009–2012) (OR = 2.08, 95 % CI 1.64–2.63, P < 0.001); days of hospital stay before ICU admission (OR = 1.26, 95 % CI 1.17–1.35, P < 0.001); mechanical ventilation (OR = 1.58, 95 % CI 1.17–2.13, P = 0.002); and continuous venovenous hemofiltration (OR = 1.54, 95 % CI 1.08–2.18, P = 0.016). The intra-ICU mortality was significantly higher among patients with late diagnosis as compared with early diagnosis (26.9 % vs 17.1 %, P < 0.001). Diagnostic delay was one independent risk factor for mortality (OR = 1.36, 95 % CI 1.03–1.81, P < 0.001).ConclusionsLate diagnosis of community-acquired influenza A (H1N1)pdm09 virus infection is associated with a delay in ICU admission, greater possibilities of respiratory and renal failure, and higher mortality rate. Delay in diagnosis of flu is an independent variable related to death.

Highlights

Patients infected with influenza A (H1N1)pdm09 virus requiring admission to the Intensive care unit (ICU) remain an important source of mortality during the influenza season
The diagnosis was established within the first week of hospital admission in 2059 (85.0 %) patients, 1314 (63.8 %) of whom were classified into the early diagnosis group and 745 (36.2 %) into the late diagnosis group (Fig. 1)
In the logistic regression analysis, independent variables related to a delay in diagnosis of influenza A (H1N1)pdm09 virus infection were as follows: age (OR = 1.02, 95 % Confidence interval (CI) 1.01–1.03, P < 0.001); first seasonal epidemics (2009–2012) (OR = 2.08, 95 % CI 1.64–2.63, P < 0.001); stay of in-patient care before ICU admission (OR = 1.26, 95 % CI 1.17–1.35, P < 0.001); and need for mechanical ventilation (OR = 1.58, 95 % CI 1.17–2.13, P = 0.002) and continuous venovenous hemofiltration (OR = 1.54, 95 % CI 1.08–2.18, P = 0.016) (Table 1)

Summary

Introduction

Patients infected with influenza A (H1N1)pdm virus requiring admission to the ICU remain an important source of mortality during the influenza season. The objective of the study was to assess the impact of a delay in diagnosis of community-acquired influenza A (H1N1)pdm virus infection on clinical outcome in critically ill patients admitted to the ICU. Since the 2009 H1N1 influenza pandemic, patients with influenza A (H1N1)pdm admitted to the ICU remain an important source of mortality during the influenza season [1, 2]. The clinical impact of a delay in the diagnosis of influenza A (H1N1)pdm09virus infection is unknown, in those patients requiring admission to the ICU

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