Severe pandemic (H1N1)v influenza A infection: report on the first deaths in Spain

Abstract

Background and objective: The impact of pandemic influenza A (H1N1)v infection is still unknown but it is associated with a high case-fatality rate.

Methods: This was a prospective, observational, multicentre study conducted in 144 Spanish intensive care units. Demographic and clinical data were reviewed for all cases of pandemic influenza A (H1N1)v infection reported from 23 June 2009 through 11 February 2010 and confirmed by reverse transcriptase PCR assay.

Results: Out of 872 cases reported by statewide surveillance, data for the first 131 deceased patients were analysed. Thirty-seven patients (28.2%) died within the first 14 days. The median age of these patients was 46 years (interquartile range 35-58) and 60.3% were male. Twenty-eight patients (21.4%) did not present with any comorbidities on admission. Forty-six per cent of patients were reported to be obese and 22 (16.8%) had COPD. The vast majority of the patients (72.5%) had viral pneumonia; 95.4% of these had bilateral patchy alveolar opacities (predominantly basal), affecting three or four quadrants. One hundred and fifteen patients (87.8%) developed multi-organ dysfunction syndrome. Ninety-seven patients (74%) required vasopressor drugs, 37 (27.2%) received renal replacement therapy, and 47 (35.1%) received intravenous corticosteroids on admission to the intensive care unit. Only 68 patients (51.9%) received empirical antiviral treatment.

Conclusions: One-third of patients with pandemic influenza A (H1N1)v infection died within the first two weeks and these were young patients, with rapidly progressive viral pneumonia as the primary cause of admission. Obese patients were at high risk but one in four patients did not present with any risk factors on admission. Only half the patients received empirical antiviral therapy and this was administered late.