Clinical factors predictive of pneumonia caused by 2009 pandemic H1N1 influenza virus

Kittisak Sawanyawisuth, Sawan Kanchana, Supannakhon Kanchana, Teerapon Vijitsopa, Kreeta Thammakumpee and Sukit Yamwong

: J Antivir Antiretrovir

Abstract :

P neumonia is the most common cause of death in 2009 H1N1 Flu (H1N1) infection. Clinical risk factors for pneumonia caused by this virus are still limited. We enrolled consecutive patients treated at H1N1 clinic, Thungsong hospital, Thailand from June to December 2009 who had positive PCR test for H1N1. Clinical features between patients diagnosed with and without pneumonia were studied. There were 441 patients with positive PCR test for H1N1. Of those, 51 patients had pneumonia (11.56%). Six clinical factors predictive for pneumonia including headache, myalgia, having underlying disease, body temperature of more than 39 o C, absolute neutrophil count > 7,700 cells, and serum creatine phosphokinase (CPK) more than 200 U/L. The adjusted odds ratio (95% CI) for all six variables were 0.432 (0.193-0.967), 0.400 (0.174-0.922), 3.095 (1.435-6.675), 2.770 (1.326-5.786), 4.432 (1.944-10.101), and 2.232 (1.040-4.789), respectively. Clinical features may be a useful tool for clinicians to predict risk of pneumonia from H1N1