Heavier myasthenia gravis patients are at higher risk of having respiratory failure or other complications after their thymus is removed, a study reports.
Doctors should monitor such patients closely to prevent severe postoperative complications, researchers contended. The thymus is a gland in the chest that plays a role in the immune system.
The study, “Influence of body mass index on postoperative complications after thymectomy in myasthenia gravis patients,” was published in Oncotarget.
There is no cure for myasthenia gravis, but current therapies can help patients manage their symptoms, which include difficulty breathing and, in severe cases, respiratory failure.
Recent studies have shown that removal of the thymus – an operation known as a thymectomy – can be an effective way to treat myasthenia gravis. In addition, a report on a Phase 3 clinical trial indicated that patients who have a thymectomy and take prednisone had better outcomes than those on the medicine alone.
A thymectomy is costly and may not eliminate the disease. Doctors can identify which patients could benefit the most from it by understanding the risks associated with it, however.
Previous reports have suggested that obesity can increase the risk of a patient developing a thymectomy complication. Some researchers have disputed this finding, however.
The study that researchers at China Medical University’s First Affiliated Hospital conducted covered both overweight and obese patients. The team looked for any complications that heavier myasthenia gravis patients developed after a thymectomy. They were particularly interested in severe complications, such as respiratory failure.
Researchers studied 59 patients whose thymus had been removed. Twenty-four had a mass in their thymus, called a thymoma, that explained respiratory problems before their operation, such as chest pain, shortness of breath and coughing.
About 14 percent had post-operative respiratory failure that required additional treatment or secondary surgery.
Obese patients had a higher rate of post-operative respiratory failure than other patients, researchers found. In addition, almost 9 percent of heavier patients experienced a myasthenic crisis — a worsening of muscle weakness that can lead to respiratory failure.
The findings indicated that both overweight and obese patients were at higher risk of developing post-operative respiratory failure, the researchers said.
In addition, heavier patients required longer hospital stays after surgery than those who weighed less, the team said. They found no differences in surgery time between the groups, however.
Myasthenia gravis with a body mass index “indicating overweight or obesity have a higher risk of postoperative complications after thymectomy,” the researcher wrote. “Thus, close monitoring must be performed when surgery is necessary.”