Bleeding injuries in sports are rare, but low clotting factors raise risk

Clotting factor levels below 10% linked to sports-induced bleeding, study finds

Andrea Lobo, PhD avatar

by Andrea Lobo, PhD |

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Incidences of bleeding from playing sports are rare among people with hemophilia, and more likely to occur in those with lower levels of clotting factors — proteins that play a key role in promoting blood clotting — a study in the Netherlands has found.

More specifically, the study reveals that patients with clotting factor activity levels below 10% were twice as likely to have sports-related bleeding, than those with levels above 10%. Disease severity was not associated with an increased risk of sports-induced bleeding.

“The results of this study emphasize the importance of clotting factor levels in prevention of bleeds,” researchers wrote. “This information is vital for patient counselling and tailoring prophylactic treatment with clotting factors and non-replacement therapy.”

The study, “Clotting factor activity levels and bleeding risk in people with haemophilia playing sports,” was published in the journal Haemophilia.

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New treatments have made it possible for more patients to participate in sports

People with hemophilia, a bleeding disorder caused by deficiencies in specific clotting factors — proteins that help blood form clots to prevent excessive bleeding — are at an increased risk of experiencing spontaneous muscle bleeds and developing joint problems.

With improved treatment options, particularly clotting factor preventive treatments (prophylaxis), the possibility of people with hemophilia to practice sports has increased significantly.

Although the World Federation for Haemophilia still encourages low-risk sports, hemophilia patients receiving prophylaxis are currently as active in sports as the general population, including participating in activities with a high risk of injuries like soccer.

Sports participation is associated with an increased risk of injuries, and there might be specific risks for those with hemophilia, namely joint or intracranial bleeding. However, data on sports injuries and bleeding among hemophilia patients are sparse, and its assessment is needed to provide adequate counseling.

In this study (NTR6769), researchers at the University Medical Centre Utrecht analyzed data from 125 hemophilia patients (41 children and 84 adults) with the goal of evaluating the risk of sports-related bleeds and injuries, as well as the impact of clotting factor levels on those risks.

These results suggest that sports participation for [people with hemophilia] is safe while at sufficient factor levels.

Patients in study played sports at least once a week

Hemophilia patients included in the study were 6 to 49 years old and played sports at least once a week. They were recruited to participate in the study from October 2018 until March 2020, and each patient was followed for 12 months. Data were compared with information from individuals in the general population, which included 2,072 male participants (645 children and 1,427 adults).

Most patients (90%) had hemophilia A, and nearly half (48%) had severe hemophilia. The majority of those with severe disease (95%) used prophylactic treatment, usually three times weekly, except for two boys in high-level high-risk sports who were on daily prophylaxis.

Although treatment frequency was similar in children and adults, children were treated with a higher dose than adults. Patients had an annual bleeding rate and an annual joint bleeding rate of zero.

Participants reported a total sports exposure of 15,999, equating to 2.5 times per participant per week. Children were involved mostly in soccer (40%), fitness (7%), and gymnastics (4%), while adults practiced fitness (29%), running (16%), and soccer (8%). Many (59%) practiced at least one high-risk sport, which involved a higher proportion of children than adults (85% vs. 46%).

One-third (34%) of the participants had no injuries, while 51 out of the 125 who reported injuries had sports-related injuries (41%). In total, 184 injuries were reported, of which 87 (47%) were sports-related. Most sports injuries affected muscles (42%) and joints (35%).

More patients with severe hemophilia reported injuries than those with non-severe disease (53% vs. 29%) and a higher median number of injuries.

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Rate of sports-related injuries was similar in patients and general population

Compared with the general population, total sports participation was similar and was associated with a similar injury incidence over the course of three months.

Most participants (62%) reported no bleeds during follow-up, with 16% reporting sports-induced bleeding.

These bleeds, which occurred in 30% of sports injuries, were associated with lower levels of clotting factors at the time of injury, meaning that participants with higher clotting factor levels were less likely to experience sports-associated bleeding.

For instance, the researchers found that patients with clotting factor activity levels below 10% during a sports injury had a bleeding risk of 41%, while those with clotting factor activity levels greater than 10% at the time of injury had a bleeding risk of 20%.

However, sport-related bleeding was not associated with hemophilia severity, joint health, sports risk category, or sport intensity.

“These results suggest that sports participation for [people with hemophilia] is safe while at sufficient factor levels,” the researchers wrote.

“Clinicians and [people with hemophilia] can use this result to aim for appropriate factor levels during sports and to inform patients, caregivers and other peers about the risks and benefits of sports participation, in particular in those using prophylaxis,” they wrote.