Risk factors for severe outcome of cases with pandemic influenza A(H1N1)pdm09

OBJECTIVES: The aim of this study is to describe demographic, clinical and epidemiological characteristics of cases with laboratory-confirmed pandemic influenza virusA(H1N1)pdm09 reported in Slovakia from May 28, 2009 to December 30, 2009 and analyse the association between risk factors and severe outcome of these cases. BACKGROUND: In the spring of 2009, an outbreak of a pandemic influenza virus A(H1N1)pdm09, emerged in Mexico and spread globally. Until December 2009, 1,014 cases were notified in Slovakia. METHODS: The data were collected within national influenza surveillance system. Odds ratios (95% Cl) were calculated. Associations were found to be significantly associated with the worse outcome (p < 0.05) in the univariate analysis and were adjusted for possible effects of age and sex by using a logistic regression model. RESULTS: Out of the total number of 1,014 cases, 131 (12.9 %) cases were hospitalized, and 43 (4.2 %) of those were admitted to intensive care units. During the reporting period, 38 deaths were reported, representing a case fatality rate of 3.75 %. The median age of severe cases (35 years, IQR = 29 y) was significantly higher than the median age of mild cases (24 years, IQR = 19 y; p <0.001). By using a logistic regression, we found out that chronic obstructive pulmonary disease (COPD) (aOR = 9.2; 95%Cl: 1.42-59.98), cardiovascular diseases (aOR = 14.97; 95%Cl: 5.49-40.79), malignity (aOR = 7.6; 95%Cl: 1.95-29.37) and gravidity (aOR = 55.21; 95% Cl: 14.40-211.58) were significantly associated with severe outcomes of the cases. CONCLUSION: The fact, that 35% of severely ill patients did not report any risk factor suggests the importance of vaccination as a prevention of influenza (Tab. 2, Fig. 1, Ref. 18). Text in PDF www.elis.sk.