Metabolic syndrome as an independent risk factor of hypoxaemia in influenza A (H1N1) 2009 pandemic.

A swine-origin influenza A (H1N1) emerged as a pandemic in 2009. We investigated the association between the overweight, metabolic syndrome and the severity of disease in the confirmed cases in Qazvin province, Iran. The study sample included all patients over 12 years old with confirmed influenza A (H1N1) in the province of Qazvin, Iran, in the 2009 pandemic, excluding pregnant women. To define overweight, sex and age-specific body mass index (BMI) cutoffs recommended by the International Obesity Task Force were used. Metabolic syndrome was defined by ATP III criteria. Multiple logistic regression analysis was performed to identify statistically independent predictors of hypoxaemia. Out of 55 confirmed cases, 28 (50.9%) were overweight and 24 (45.3%) were identified as having metabolic syndrome by ATP III criteria. Twenty four patients had hypoxaemia (arterial oxygen saturation below 90%) during the course of the disease. In multivariate logistic regression analysis, pulmonary co-morbidity (OR=9.54; 95% CI, 1.36 to 66.88; p= 0.023) and the metabolic syndrome (OR=18.66; 95% CI, 1.60 to 217.47; p= 0.019) were revealed to be independent risk factors for hypoxaemia in influenza A (H1N1) pdm09. The results of the present study reveal the role of the metabolic syndrome on the severity of influenza A (H1N1) pdm09 infection.