The study, released Thursday, found that, since the outbreak of H1N1 last April, the number of hospitalized H1N1 patients needing intensive care was 50 per cent higher than those with regular flu or pneumonia, the most common complication of seasonal flu.
One in six H1N1 patients in hospital was admitted to the ICU, the study found. Of those admitted to hospital, one in 10 patients needed ventilation to help them breathe. That was more than double the number of seasonal flu or pneumonia patients requiring ventilation.
Young people were also hardest hit by the H1N1 virus, the study found. The median age for patients hospitalized with H1N1 was 28, while the median age was 71 for seasonal flu. Those who died from H1N1 were about 30 years younger than patients who died from seasonal flu or pneumonia.
H1N1 patients in the ICU were also, on average, younger than those with seasonal flu or pneumonia -- with H1N1 patients being in their mid-40s while influenza or pneumonia patients were in their late 60s.
Kathleen Morris, head of emerging issues at CIHI, said the study gives input to hospitals as they sit back to review and tweak their pandemic plans.
"I think, in many cases, it did confirm what clinicians sensed from treating patients with H1N1," said Morris, adding the study also raises a lot of questions.
"Why were the patients so much younger, why did they need more ICU care? I think the study is a good springboard for others to do research on it," she said.
The study also examined the impact of H1N1 on pregnant women. One in five women of child-bearing age hospitalized with H1N1 was pregnant, more than would be expected in a regular seasonal flu year. Four pregnant women diagnosed with H1N1 died since the outbreak of the virus in April last year, while there were no deaths among pregnant women from the regular seasonal flu the previous year.
Morris said more research is needed to understand why more pregnant women were hospitalized with H1N1 compared to regular seasonal flu.
The study coincides with an announcement Thursday from the World Health Organization that its emergency panel of swine flu experts will meet later this month to determine if the H1N1 pandemic is tapering off.
As of Jan. 31, the global death toll from swine flu was 15,174, according to the UN agency.
-- Canwest News Service