Severe 2009 pandemic influenza A (H1N1) infection and increased mortality in patients with late and advanced HIV disease.

OBJECTIVE

To describe the clinical course of infection by 2009 (H1N1) influenza virus in different stages of HIV disease.

DESIGN

Prospective, observational study.

METHODS

During the pandemic period, HIV-infected patients presenting respiratory symptoms at a third level referral hospital in Mexico City were tested for 2009 influenza A (H1N1) viral RNA. Clinical files were prospectively analyzed.

RESULTS

Infection by H1N1 was confirmed in 30 (23.8%) of the total 126 HIV-infected patients studied. In the group of patients with 2009 H1N1 virus infection, 16 (53.3%) were hospitalized, 12 (40%) had active opportunistic infections and six (20%) died. In the group of 96 patients not infected with 2009 H1N1 virus, 54 (56.25%) were hospitalized with opportunistic infections and 12 (12.5%) died. For all hospitalized patients, being on HAART and having undetectable HIV viral loads at hospitalization was associated with higher survival (P = 0.019). Patients with 2009 H1N1 virus infection had a higher mortality rate, even after adjusting for HAART (P = 0.043). Coinfection by HIV and H1N1 2009 virus was more severe in patients with opportunistic infections, as shown by longer hospital stays (P = 0.0013), higher rates of hospitalization (P < 0.0001), use of mechanical ventilation (P = 0.0086) and death (P = 0.026). Delayed administration of oseltamivir in hospitalized patients was significantly associated with mortality (P = 0.0022).

CONCLUSION

Our data suggest that infection by 2009 H1N1 is more severe in HIV-infected patients with late and advanced HIV disease than in well controlled patients under HAART.