Conducted at eight hospital centres in Quebec and Ontario, the two-year study suggests that apart from the well-known risks of pulmonary embolism, DVT patients also face postthrombotic syndrome (PTS), a long-term complication that is not addressed by traditional treatment approaches like blood thinners.
A research article published in the Annals of Internal Medicine reveals that the study followed 387 patients.
"Incredibly, we found as many as 43 per cent of the patients developed postthrombotic syndrome, and one-third of those had moderate to severe cases," said McGill University's Dr. Susan R. Kahn, lead author of the study.
"The syndrome is characterized by persistent leg pain and swelling, and in severe cases, patients can develop painful leg ulcers which are very difficult to treat.
"Contrary to popular belief, DVT doesn't just affect older people, it can affect adults of all ages. Developing postthrombotic syndrome and similar complications have been shown to lead to significant disability, lost workdays and very poor quality of life," she added.
Kahn and her colleagues-including researchers from Universite de Montreal, McMaster University and other institutions-also attempted to identify risk factors that made certain patients more likely than others to develop PTS.
They found that older patients who had suffered a previous bout of DVT, and those with larger blood clots at the time of diagnosis, faced a greater risk of developing PTS.
The team also observed that the risk of developing PTS was far higher in patients still experiencing leg symptoms one month after DVT was first diagnosed and treated.
"This suggests that physicians can predict if a patient is likely to develop chronic PTS as early as one month after DVT diagnosis. Our results show that current modalities to treat acute DVT are not effective in preventing chronic complications of DVT, and emphasize the need for additional research in the prevention and treatment of PTS," Kahn said.