VANCOUVER — A lack of data tracking Canadians who have had COVID-19 could hinder efforts to understand potential post-infection conditions, such as diabetes and brain fog, experts have warned.
They say the impact of the pandemic on Canadian health systems and society could linger for years but preparing for this is challenged by the data void.
Dr. Kashif Pirzada, an emergency physician at Toronto's Humber River Hospital, said reliance on at-home rapid testing for COVID-19 is a major hurdle in data collection.
"They're not centrally tracked and there are very few resources available to these patients," he said, even though COVID-19 seemed to cause diabetes, brain fog or other conditions "very frequently."
"If five or 10 per cent of our population becomes disabled, which is some of the rates we're looking at, that's going to be a huge issue for our workforce, for overall health," said Pirzada, who is also an assistant clinical professor at McMaster University.
Dr. Akshay Jain, an endocrinologist in Surrey, B.C., said Canada "might be seeing an avalanche of diabetes cases coming out of the COVID pandemic."
But Jain said that as far as he knows, Health Canada is not collecting data on the after-effects of COVID-19.
People with mild symptoms often failed to follow up with their doctors, worsening the data situation, said Jain, who also highlighted the reliance on home testing as problematic.
"I just feel that the health-care system as well as the public needs to know about both the immediate short-term as well as the long-term effects of COVID," Jain said.
"You know, the repercussions of the pandemic will stay with us for many more years. So, I think we need to be cognizant of this and watch out for conditions like diabetes and complications that arise as a result."
Asked whether and how it was tracking post-COVID-19 conditions and people who had had the illness, Health Canada provided a series of links to information about vaccination, and a daily update of new cases.
"Health systems are the responsibility of each province and territory," it said.
Jain said studies in the United States and Germany show the risk of developing diabetes is about 46 per cent higher for those who have had COVID-19 compared with those who haven't been infected.
It's not clear why people with COVID-19 are developing diabetes, said Jain.
One theory is that COVID-19 causes a "tsunami of inflammation," which increases insulin resistance, he said, while another is that steroids used to treat severe COVID-19 might lead to diabetes.
About nine per cent of Canadian adults have been diagnosed with diabetes, Jain said. But pre-diabetes and undiagnosed diabetes push the figure to nearly 30 per cent, he said.
"This is already a very high number and then throwing COVID in the mix, these numbers are probably going to go up even higher."
In October 2020, Madhu Rao of Toronto tested positive for COVID-19. Eighteen months later he said he still "felt breathless every now and then."
Rao said he worried it was something to do with his heart, because he read COVID-19 was causing cardiac problems.
A checkup revealed instead that he was a "borderline diabetic" with high blood glucose levels, said Rao.
He said he had no issues with his blood sugar before getting COVID-19 and described himself as otherwise healthy and active with weight in the normal range.
His doctor told him that she was seeing a lot of patients with high blood sugar levels and some developing diabetes after COVID-19, and put him on a strict diet, he said.
"She told me all I can do is to keep postponing its onset."
A November 2020 study in the journal Diabetes, Obesity and Metabolism said 14.4 per cent of COVID-19 patients had been diagnosed with diabetes.
"Recent reports have shown that newly diagnosed diabetes may confer a greater risk for poor prognosis of COVID-19 than no diabetes or pre-existing diabetes," it said.
"Therefore, COVID-19 patients with newly diagnosed diabetes should be managed early and appropriately and closely monitored for the emergence of full-blown diabetes and other cardiometabolic disorders in the long term."
Jain said he agreed, and "everyone with mild COVID" should talk to a doctor about whether they should be screened for diabetes.
Another condition commonly associated with COVID-19 is the sense of confusion known as brain fog. An analysis of several studies on the issue in the Journal of the Neurological Sciences in March said up to 32 per cent of patients reported brain fog about three months after getting COVID-19.
Prof. Teresa Liu-Ambrose, the Canada Research Chair at the University of British Columbia's Djavad Mowafaghian Centre for Brain Health, said there isn't enough data to know how many Canadians have been affected by the condition, how permanent it is, and what the symptoms and consequences are.
Liu-Ambrose said the Canadian Longitudinal Study on Aging, a long-term countrywide research project, is imaging subjects' brains and assessing their cognition over the next three years to identify differences between people who had COVID-19 and those who had not.
However, she said memory fog was largely a subjective complaint, so quantifying it could be challenging.
Dr. Jurgen Maslany of Saskatchewan tested positive for COVID-19 in March, then went back to work about two weeks after he thought he had fully recovered.
But after attending a patient he couldn't remember the details of what they had discussed, and he realized "something was off".
"And so, I immediately took myself off work because it wasn't safe," Maslany said.
There was also a sense of anxiety, although he wasn't sure if this was a symptom of brain fog or worrying about it.
"It felt like something was just sort of chemically off in my head," he said.
It took about three weeks for the symptoms to plateau, and now he feels back to normal, he said.
But Liu-Ambrose said no one knows what will happen if brain fog is left untreated.
"Any long-term impact of COVID-19 on the brain and our cognition can be significant," Liu-Ambrose said.
"These changes could potentially be related or predictive of future decline or dementia risk. We don’t know — but there certainly is that possibility if these subjective complaints are reflective of actual changes in the brain.
"It's an emerging area that needs to be addressed and needs to be studied to a greater extent."
Even a modest risk of post-COVID conditions could add up to a substantial burden on health care, given a high number of COVID cases.
Jain, the diabetes expert, said American data showed an additional 18 cases of diabetes per 1,000 people if they had COVID-19.
That could translate into "thousands more Canadians at the risk of developing Type 2 diabetes," he said, requiring closer monitoring for diabetic complications including heart attack, stroke, kidney damage and vision loss.
"If we look at the entire picture together, we're looking at a huge burden on the Canadian health care system that we haven't yet acknowledged but it's just waiting to happen."
As for former COVID-19 sufferer, Rao said, it's probably a good idea to pay attention to every single symptom after getting the illness.
"Had I just ignored it as getting tired physically or something, I wouldn't have found out that my blood sugar levels are rising."
Maslany, speaking both as a doctor and a person who experienced the lingering after-effects of COVID-19, said it was "critically important to keep on top" of complications of this disease.
"I am not confident that we're going to be able to find certain therapeutic options, especially in the short term, but I think it's important to collect the data," he said.
"First of all, you can't analyze and fix a problem unless you have all the proper data."
This report by The Canadian Press was first published June 4, 2022.
Hina Alam, The Canadian Press