Risk of dying falls: study

19% fewer deaths one year after hospitalization

The risk of dying within one year of hospitalization in Ontario fell significantly between 1994 and 2009, according to a new study by an Ottawa research scientist.

The study looked at the oneyear survival of more than 2.5 million Ontarians who were admitted to hospital in 1994, 1999, 2004 and 2009.

It found that crude oneyear mortality actually rose to 11.6 per cent from 9.2 per cent during that 15-year period. But it also found that people admitted to hospital were significantly older, sicker and in more acute need of care in 2009 than they were in 1994.

“When you adjust for those factors, the adjusted risk of death decreased significantly over time,” said Carl van Walraven, a senior scientist with the Ottawa Hospital Research Institute, who did the research at the Institute for Clinical Evaluative Sciences’ (ICES) satellite site at the University of Ottawa.

Moreover, the study found that the one-year risk of death in the general population also decreased by 24 per cent during the study period.

Taking that into account, as well as the differences in the patient population, the study concluded that people hospitalized in 2009 were 19 per cent less likely to die within the subsequent year.

‘This is absolutely fantastic news for anyone who is interested in their health care.’

CARL VAN WALRAVEN senior scientist, Ottawa hospital research Institute

The drop in risk of death is so extensive, the study says, that “these changes translate into a meaningful decrease in life-years lost.”

“This is absolutely fantastic news for anyone who is interested in their health care,” van Walraven said in an interview. “It shows that, as far as this outcome is concerned — one-year mortality — outcomes are improving.”

The reasons for the improvement cannot be determined from the data, the study says. But van Walraven has a hypothesis.

“I think it’s a combination of improved treatments for specific diseases and an overall increased emphasis on lifestyle changes in patients,” he said. “That’s my hunch.”

The improvement likely reflects improved quality of care in hospitals as well as in the community, he said. “It’s a oneyear survival, so it’s not just what’s happening in the hospital that’s influencing this.”

The study suggests the improved survival rate may reflect advances in medical care, such as aggressive use of statin drugs for coronary artery disease, ACE inhibitors and beta blockers for congestive heart failure, implantable defibrillators for sudden cardiac death, hormone treatments for breast cancer and effective antiretroviral therapy for AIDS.

The positive effects of preventive health strategies might further explain the results, the study says. “It is possible that a greater focus on lifestyle modifications over the study period contributed to the improved outcomes.”

It’s possible that changes in hospital admission patterns could explain part of the decrease, the study notes. Patients with a poor prognosis may have been more likely to be admitted to hospital for work-up or palliation in 1994 than in 2009.

The study was published Monday in the Canadian Medical Association Journal.