High mortality from respiratory failure secondary to swine-origin influenza A (H1N1) in South Africa.
BACKGROUND
The novel influenza A (H1N1) pandemic affected South Africa late during the 2009 Southern hemisphere winter and placed an extra burden on a health care system already dealing with a high prevalence of chronic lung diseases and human immunodeficiency virus (HIV) infection.


OBJECTIVE
The aim of this study was to describe the epidemiological characteristics, clinical features, management and outcomes of patients with confirmed influenza A (H1N1) infection complicated by respiratory failure.


METHODS
We included all adult patients with confirmed influenza A (H1N1) infection that were referred to the medical intensive care unit of a large academic hospital in Cape Town for ventilatory support in this prospective observational study.


RESULTS
A total of 19 patients (39.5 +/- 14.8 years) needed ventilatory support over a 6-week period. Of these, 15 were female and 16 had identifiable risk factors for severe disease, including pregnancy (n = 6), type 2 diabetes mellitus (n = 6), obesity (n = 4), HIV infection (n = 3), immunosuppressive therapy (n = 3) and active pulmonary tuberculosis (n = 2). The most frequent complications were acute renal failure (n = 13), acute respiratory distress syndrome (n = 12) and ventilator associated pneumonia (n = 10). Thirteen patients died (mortality: 68.4%). Fatal cases were significantly associated with an APACHE II score >or=20 (P = 0.034), but not with a P(a)O(2)/F(I)O(2) <200 (P = 0.085) and a chest radiograph score >or=12 (P = 0.134).


CONCLUSIONS
The majority of patients with respiratory failure secondary to influenza A (H1N1) infection were young females and had an underlying risk factor for severe disease. The condition had a high mortality, particularly amongst patients with an APACHE II score >or=20.
Koegelenberg
C F N
CF
Division of Pulmonology, Department of Medicine, University of Stellenbosch, PO Box 19063, Tygerberg, 7505, Cape Town, South Africa. coeniefn@sun.ac.za
Irusen
E M
EM
Cooper
R
R
Diacon
A H
AH
Taljaard
J J
JJ
Mowlana
A
A
von Groote-Bidlingmaier
F
F
Bolliger
C T
CT
D000328:Adult; D017677:Age Distribution; D000368:Aged; D004196:Disease Outbreaks; D005260:Female; D006679:HIV Seropositivity / Q000150:complications; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000150:complications / Q000401:mortality* / Q000821:virology; D008297:Male; D008875:Middle Aged; D011247:Pregnancy; D011446:Prospective Studies; D012121:Respiration, Artificial; D012131:Respiratory Insufficiency / Q000209:etiology / Q000401:mortality*; D012307:Risk Factors; D012720:Severity of Illness Index; D017678:Sex Distribution; D013019:South Africa / Q000453:epidemiology; D055815:Young Adult