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Experience matters in surgeries Volume affects survival rates: Study
Thu, June 9, 2005By HOLLY LAKE, Ottawa Sun
Where you have surgery may affect how well you fare.
A report released yesterday from the Canadian Institute for Health Information (CIHI) shows patients may have a better chance of surviving some types of specialized surgeries in hospitals that perform higher volumes of the procedure.
While there has been a great deal of international research linking patient outcomes and volume, CIHI's is the first study of Canadian outcomes. It looked at 180,000 cases of nine elective procedures conducted between 1998 and 2004.
"In (no cases) did we find there were better outcomes with low volumes,"said CIHI president and CEO Glenda Yeates.
In three of the nine procedures -- angioplasty, esophagectomy and pancreatic cancer surgery known as the Whipple procedure -- a link was found between higher volumes and the risk of 30-day in-hospital mortality.
The average death rate for esophagectomy was 4.3% and 3% for the Whipple procedure. However, both procedures are very rare, with most hospitals performing less than five per year. Only a few perform more than 30.
RISK OF DEATH LOWER
CIHI found that for every 10 additional procedures performed in the hospital, the risk of death was 44% lower for an esophagectomy and 46% lower for the Whipple.
Angioplasty already had a very low death rate, but decreased further with the more procedures a hospital did.
For the other six procedures, there was no significant association between volumes and death rates, only a difference between hospitals performing the highest and lowest volumes.
"I think we do need to look at individual procedures because it is clear it varies," Yeates said. "For some procedures, (volume) may be quite important and for others it may not be a factor."
While CIHI is making interesting observations, Dr. Alan Forster, a scientist at the Ottawa Hospital Research Institute and patient safety advisor to the Ottawa Hospital, said the numbers don't prove a volume-mortality association.
"It makes sense that if you do more of something, you're going to be better at it. And that seems to be born out in the data," he said. "The question is, are there possible alternatives for the observations?"
Statistically, the data is not accounting for things like patients' smoking habits, socio-economic or nutritional status -- all of which can be predictors of outcomes, Forster said.
That's particularly true with low numbers. If a hospital is doing one procedure five times a year and all five surgeries go bad, he said it could "all be chance." But when 500 surgeries all go bad, it's probably a bad place.
"The bigger question from a policy standpoint is whether this is enough to base decisions on creating high-volume centres and closing down low-volume centres."
holly.lake@ott.sunpub.com
SURGICAL STUDIES
The nine procedures cihi studied:
- Unruptured abdominal aortic aneurysm -- Repair involves opening the abdomen, removing the aneurysm and sewing a synthetic tube in its place.
- Carotid endarterectomy -- Surgical removal of plaque deposits that are reducing or blocking blood flow in the carotid artery (found on left and right side of neck & deliver oxygen-rich blood to head and brain).
- Colon/rectal surgery -- Complete or partial removal of the colon or rectum.
- Coronary artery bypass graft -- Surgery reroutes the blood flow around blocked arteries near the heart.
- Esophagectomy -- Complete or partial removal of the esophagus, typically to treat cancer.
- Lobectomy -- Removes a lobe of the lung, typically to treat lung cancer.
- Pneumonectomy -- Surgical removal of entire right or left lung, typically to treat cancer.
- Angioplasty -- Opens a blocked coronary artery using a balloon-tipped catheter.
- Whipple surgery -- Surgical removal of the head of the pancreas and the duodenum, and sometimes a portion of the stomach and other tissues, typically to treat cancer.