Hospitalised patients with Influenza A (H1N1) in the Royal Hospital, Oman Experience of a tertiary care hospital, July–December 2009

Objectives: : the aim of this study was to describe the clinical characteristics, risk factors, laboratory investigations and outcome of hospitalised patients with positive influenza a (h1n1) at the royal hospital in oman. methods: we extracted data from the retrospective medical charts, radiological and laboratory findings of 131 patients who were confirmed as positive for influenza a (h1n1) by real-time reverse-transcriptase- polymerase-chain-reaction from 21 july to 23 december 2009. results: the median age was 24 years with 34.4% in the paediatric age group. most (63%) of hospitalised patients were female. symptoms at presentation included mainly fever (93.9%) and respiratory symptoms (89.3%). 83% of the patients had at least one risk factor and pregnancy was the most common associated condition (22.9%). most of the patients had reduced lymphocytic count (57.3%) and high levels of serum c-reactive protein, aspartate transaminase and lactate dehydrogenase (75.7%, 75% and 70.8% respectively). the majority of the patients (64.5%) had evidence of pneumonia and radiological findings constituted mainly bi-lateral infiltrates (60.6%). antiviral therapy was administered to 95.4% of the patients who mostly received it 48 hours after disease onset. death occurred in 6.9% of patients. out of these, 88.9% required intensive care unit (icu) care and mechanical ventilation. conclusion: influenza a (h1n1) infection mainly affected those of younger age and females. associated medical conditions were common,with pregnancy being interestingly the commonest risk factor. the infection caused severe illness that required icu admission and led to death in 6.9% of patients.