Risk Factors for Death from Influenza A(H1N1)pdm09, State of São Paulo, Brazil, 2009

Abstract

This case-control study aimed to assess the risk factors for death from influenza A(H1N1)pdm09 in patients with laboratory confirmation, who had severe acute respiratory illness-SARI and were hospitalized between June 28th and August 29th 2009, in the metropolitan regions of São Paulo and Campinas, Brazil. Medical charts of all the 193 patients who died (cases) and the 386 randomly selected patients who recovered (controls) were investigated in 177 hospitals. Household interviews were conducted with those who had survived and the closest relative of those who had died. 73.6% of cases and 38.1% of controls were at risk of developing influenza-related complications. The 18-to-59-year age group (OR = 2.31, 95%CI: 1.31–4.10 (reference up to 18 years of age)), presence of risk conditions for severity of influenza (OR = 1.99, 95%CI: 1.11–3.57, if one or OR = 6.05, 95%CI: 2.76–13.28, if more than one), obesity (OR = 2.73, 95%CI: 1.28–5.83), immunosuppression (OR = 3.43, 95%CI: 1.28–9.19), and search for previous care associated with the hospitalization (OR = 3.35, 95%CI: 1.75–6.40) were risk factors for death. Antiviral treatment performed within 72 hours of the onset of symptoms (OR = 0.17, 95%CI: 0.08–0.37, if within 48hours, and OR = 0.30, 95%CI: 0.11–0.81, if between 48 and 72 hours) was protective against death. The identification of high-risk patients and early treatment are important factors for reducing morbi-mortality from influenza.

Risk factors for serious outcomes associated with influenza illness in high‐ versus low‐ and middle‐income countries: Systematic literature review and meta‐analysis

“…In the review of studies that provided estimates adjusted for the presence of other factors known to impact the risk of severe outcomes for people ill with influenza, we found that the risk estimate was heterogeneous and not consistently greater or less than the pRR estimated with this meta‐analysis …”

Fueling influenza and the immune response: Implications for metabolic reprogramming during influenza infection and immunometabolism

“…[75][76][77][78][79] During influenza season, obese persons are at increased risk for hospitalization due to respiratory illness and were overrepresented among influenza-associated hospitalizations and deaths the 2009 pandemic. [80][81][82][83] Individuals with diabetes have higher blood and ALS glucose levels correlated with increased respiratory infections ( Table 1). These underlying conditions also associate with hyperglycemia, increased adipose tissue, and chronic inflammation.…”

Influenza-Associated Hemophagocytic Syndrome in Adults: Case Report and Review

“…On the one hand, the link between influenza A infection and HPS is relatively new, making it a difficult diagnosis due to the low index of suspicion and explaining why many cases have been identified postmortem [15]. On the other hand, hematological abnormalities (cytopenias) are frequently associated with influenza A infection (especially lymphopenia and trombocytopenia) [16,17] although they tend to be mild in most patients and are generally not associated with a poor prognosis. Therefore, diagnosis of HPS is easily missed if there is no clinical suspicion that takes the treating physician to order specific disease markers as proposed by HLA-04 [2].…”

“…Unfortunately, treatment was never started in many cases because of delayed diagnosis. In the study by Beutel et al [14], the median time from the onset of symptoms to the diagnosis of VAHS was 23 days (interquartile range [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. This could explain, at least in part, the poor prognosis of HPS secondary to influenza A infection.…”