The relationship between study variables and ICU admission/ in-hospital death is shown in Table 2 . In the univariate analyses, age, most comorbidities (COPD, diabetes, liver failure and cardiovascular disease), ex-smoking, corticosteroid therapy and histamine-2 receptor antagonists were associated with an adverse outcome during hospitalization. In the multivariate models, the variables significantly associated with a poor outcome were diabetes (OR¼ 2.21, 95% CI¼ 1.21 -4.02), corticosteroid therapy (OR¼ 3.37, 95% CI ¼ 1.39-8.20) and use of histamine-2 receptor antagonists (OR ¼ 2.68, 95% CI ¼ 1.14 -6.36). Use of neuraminidase inhibitors was protective (OR ¼0.57, 95% CI ¼ 0.34 -0.94). Pneumonia at admission, COPD, ex-smoking and liver failure showed a trend to association.