Frostbite amputations reached new high in Edmonton, decreased in Calgary last winter

The number of amputations due to frostbite in Edmonton reached 110 last winter, the highest level in more than a decade, according to new data obtained by CBC News.

But Calgary marked its second consecutive winter of declining frostbite amputations, counting roughly one-third of Edmonton's procedures last fiscal year.

The frostbite amputation numbers mark a notable shift after years of Alberta's two major centres following similar trends.

It is not clear what caused the sharp divergence.

But doctors and homeless advocates point to two key differences between the two cities that may have played a role: Edmonton's aggressive encampment eviction policy, and the use of a more assertive frostbite treatment protocol in Calgary's emergency departments.

"I do think that houselessness and substance abuse are certainly contributors to it, but I think there's multiple things that may be contributing," said Dr. Scott MacLean, an emergency physician at Edmonton's Royal Alexandra Hospital.

According to data from Alberta Health Services, the Edmonton health zone saw 110 amputations with a diagnosis of frostbite during the fiscal year of 2023-24.

That's up from 71 the previous year, and surpasses the previous record of 91 amputations in 2021-22.

The Calgary zone counted roughly one-third of Edmonton's numbers last year.

The health zones include areas well beyond the two cities. Banff and Claresholm are in the Calgary zone, while the Edmonton zone includes Morinville and Evansburg.

AHS does not release health statistics between one and nine on privacy grounds, arguing that an individual could potentially be identified from such a small group.

Because Calgary had one month in the past fiscal year where the number of frostbite amputations was less than 10 but greater than zero, the annual total is only known to be between 32 and 40.

The sharp divergence between Edmonton and Calgary is unusual, as data going back to 2011 shows that the two cities have largely followed the same trends without any significant difference in annual numbers.

Reasons for the discrepancy are not clear.