WINNIPEG -- Half of all Canadians needing priority procedures like joint replacement or cataract surgery waited longer than the recommended time during the first wave of COVID-19, according to new data from the Canadian Institute for Health Information (CIHI).

The institute took data from the first six months of the pandemic to see how surgeries were affected by the first wave.

CIHI said it found cancelled and delayed procedures during the pandemic led to longer wait times for joint replacements and cataract surgeries in 2020.

"What I think we probably knew when things had to be cancelled, was there was going to be challenges with waits. What the full impact of that (is) will be hard to tell until we have further data," said Tracy Johnson, director of health system analytics at CIHI.

The data shows around half of Canadians did not receive their procedures within recommended time frames, compared with around one-third in 2019.

CIHI found urgent procedures like radiation therapy and hip fracture repair wait times were not affected as much.

Most Canadians continued to receive care within benchmark periods, and the number of procedures done was comparable with that completed in 2019.

The data also shows for people who received breast, bladder, colorectal, and lung cancer surgery, the median wait times improved by two or three days. The number of cancer surgeries did decrease by about one-fifth compared with 2019, though.

According to CIHI, wait times for magnetic resonance imaging (MRI) scans continued to be longer than those for computed tomography (CT) scans, although the number of diagnostic imaging scans decreased. The institute said wait times varied across provinces.

The decrease in diagnostic imaging is a concern for CIHI since they are key in diagnosing cancer.

"The decreases in the number of diagnostic imaging scans have already been flagged as a challenge for areas like cancer, where 25 per cent of diagnostic imaging is scans for cancer."

Johnson said without imaging, cancer can go undetected for a longer time, which typically lends itself to worse outcomes.

Moving forward, Johnson said provinces will need to start addressing the longer wait times and dealing with the backlog.

"It's been identified that one of the key challenges about the cancellations is about how we get to that backlog and how we get through that backlog," said Johnson.

"We know we have available operating room pace after hours in Canada," Johnson said. "Our biggest challenge will be health human resources, so nurses, anesthesiologists, and physicians. That is really the limiting factor."

CIHI said it is currently working on surgery data from March to June 2021.