Thousands of patients taking advantage of Canada's first online health records system say it is giving them control over their care, but some experts are warning too much information can cause panic.

"Showing patients the information without interpretation does have risks of confusing patients and increasing anxiety," said Alexander Krist, a professor at Virginia Commonwealth University in Richmond who has studied the value of giving patients access to their health records.

Blood pressure data from consumer medical products can be uploaded into MyChart. (Michael Holahan/Associated Press)

"And showing patients information before their doctors have had a chance to explain it to them can also be problematic."

Sunnybrook Health Sciences Centre in Toronto is the first in Canada to offer its patients virtual access to their health records, using an online network called MyChart, and other hospitals are poised to follow suit.

The portal allows patients to create a personal health record, schedule appointments, read educational materials and give other physicians or family members access to their files.

Evidence of benefits unclear: professor

But some researchers say the effectiveness of e-health technologies is unproven, and fear some patients may mistake a shadow on an ultrasound for a tumor.

"There are all sorts of claims about these technologies that they save lives and reduce the number of hospital admissions, but the evidence on effectiveness isn't particularly strong," said Aziz Sheikh, a professor of primary care research at Scotland's University of Edinburgh.

"A lot of these claims may well prove to be true in the future, but at the moment they're actually quite difficult to substantiate."

The effectiveness of a system like MyChart may depend on whether health records present information in lay language, not medical jargon, and offer medical advice specific to each patient, Krist said.

"One of the challenges with creating information systems for patients is to make the information useful and actionable for patients," he said.

Sunnybrook commended

Krist said Sunnybrook should be commended for launching a system that will give its patients more information about their condition and care than they would traditionally get.

But ideally a system such as MyChart would also interpret test results and post-operative notes for patients, not just lay out the facts.

"The solution is to develop better systems and processes for informing patients of their results, and explaining to them what it means so that it doesn't create anxiety," Krist said.

Sarina Cheng, director of e-health at Sunnybrook, said the 10,500 patients now using MyChart haven't complained about feeling anxious after viewing their records.

The online portal has increased patient and family participation, improved relationships between patients and clinicians and has helped patients ask informed questions, she said.

"We've had lots of feedback from patients, and they do believe that knowing and having that information available is important," Cheng said.

Patient pleased

Nancy Leonardis, a Sunnybrook patient confined to bed rest for the duration of her pregnancy, says MyChart allows her to check her test results, research the drugs she's been prescribed and show her husband her ultrasound pictures.

"You can be an advocate for your own health," said Leonardis, 34.

Leonardis also goes online to help care for her mother, Grace Russo, who is battling metastatic breast cancer.

Kevin Leonard, a professor of e-health at the University of Toronto, said allowing patients to access their health records empowers them to take a more active role in their care.

"We can't say that patients accessing information is a bad thing because one patient out of 10,000 will look at it and freak out," he said.

Research into e-health is sparse, but it has been proven that when patients are involved in their care, their health improves.

MyChart was first launched as a pilot in 2006, and limited to osteoporosis patients.

Gradually, it was made available to all Sunnybrook patients, and the hospital started actively promoting it to patients as they register several months ago.

Sunnybrook is working with the Baycrest hospital for the elderly in Toronto as well as the Central Community Care Access Centre, a network of more than a dozen clinics, to make MyChart available to their patients.