Predictors of mortality in hospitalized children with pandemic H1N1 influenza 2009 in Pune, India

Abstract

Objective: To analyse the factors associated with increased mortality among Indian Children with H1N1.

Methods: Data were abstracted from available hospital records of children less than 12 y of age, who were admitted to Sassoon General Hospital in Pune, India, with confirmed pandemic 2009 H1N1 influenza infection from August 2009 through January 2010. Logistic regression analysis was used to identify clinical characteristics associated with mortality.

Results: Of 775 pediatric cases admitted with Influenza Like Illness (ILI), 92 (11.8%) had confirmed H1N1 influenza infection. The median age of HIN1 cases was 2.5 y; 13 (14%) had an associated co-morbid condition. Median duration of symptoms was 4 d (interquartile range (IQR), 3-7 d). All 92 H1N1 cases received oseltamivir and empiric antimicrobials on admission. Intensive care unit (ICU) admission was required for 88 (96%) children, and 20 (23%) required mechanical ventilation.Fifteen children (16%) died; mortality was associated with presence of diffuse alveolar infiltrate on admission chest radiography (odds ratio (OR) 45, 95%CI :5.4-370; p < 0.001), use of corticosteroids in ARDS in children who required mechanical ventilation (OR 8.12, 95%CI: 2.44-27.05; p = 0.001), SpO(2) <80% on admission (OR 32.8, 95% CI: 5.8-185.5; p < 0.001) and presence of ARDS (OR 345.3, 95% CI :33.5-3564.1; p < 0.001). Necropsy from all children who died showed 9 (60%) had ARDS pattern and necrotizing pneumonitis, diffuse hemorrhage and interstitial pneumonia (n = 4 each, 27%) with gram positive organisms consistent with severe viral and bacterial co-infection.

Conclusions: Hypoxia, ARDS and use of corticosteroids in children with ARDS who were mechanically ventilated were the factors associated with increased odds of mortality. Necropsy also suggested bacterial co-infection as a risk factor.

Fig. 1

Children with Influenza-like Illness (ILI) <12 y of age admitted to SGH and among those who were PCR confirmed H1N1 infected: August 2009–January 2010

Fig. 2

a. Well formed hyaline membrane with some partially atelectatic alveoli with sparse infiltrate of macrophages. b. Alveoli filled with dense exudate of polymorphs with scanty mononuclear cell, fibrin deposition, intra alveolar hemorrhage, necrosis of alveolar wall with micro abscess formation and marked congestion of alveolar capillaries