[The analysis of the clinical features between survivors and non-survivors with the severe form of new influenza A (H1N1) viral infection].

OBJECTIVE

To understand the clinical features of critically ill patients with pandemic 2009 influenza A (H1N1) and investigate the risk factors associated with death cases.

METHODS

The clinical features of 55 critically ill patients with pandemic 2009 influenza A (H1N1) viral infection hospitalized at Beijing Ditan Hospital from October 3 to December 15, 2009 were retrospectively analyzed, and a comparative analysis was performed on the manifestations of the survival and the death groups of patients.

RESULTS

There were 31 males and 24 females. The age ranged from 10 months to 84 year old, and the mean (SD) was 38 (20) year old. The critically ill cases were more in patients under age 65 (48/55), with obesity (33/49), with underlying diseases (26/49), and pregnancy (6/24). Both the survivors and non-survivors of patients had high fever, cough, sputum (some sputum with blood), dyspnea, räles of both lungs fields, and all further developed severe pneumonia. The patients also showed respiratory failure (54/55) and ARDS (26/55). All of them received oseltamivir therapy, and 38 patients received mechanical ventilation and 30 were given steroid therapy. Secondary infection occurred in 27 cases, and ventilator-associated pneumonia happened in 10 patients. In the early stage of onset, C-reactive protein (CRP) increased [(131 ± 130) mg/L] and low counts of T lymphocytes were present [CD(4)(+), CD(8)(+) T was (217 ± 139)/µl and (162 ± 82)/µl]. With the progress of disease, the non-survival cases had persistently increased CRP and the counts of T lymphocytes did not recover, while the secondary fungal infection was significantly higher than in the survivor cases (P < 0.05). By using BMI, underlying diseases, ARDS, the day of Oseltamivir initiated, steroid therapy, following bacterial and fungal infection as variables through logistic regression analysis, it was shown that higher BMI and following fungal infection were associated with higher fatal risks (OR was 6.512, 19.631 respectively, both of P value was low than 0.05). There was no death case who received oseltamivir treatment within 48 hours of onset of disease.

CONCLUSIONS

Critical illness in pandemic 2009 influenza A (H1N1) was associated with patients under age 65, with obesity, underlying diseases, and pregnancy. Persistently increased CRP and lower counts of T lymphocytes were associated with unfavorable prognosis. The patients with higher BMI and secondary fungal infection had higher fatal risks. Oseltamivir treatments at early stage would probably reduce mortality.