Leech treatment relieves the excruciating knee pain of arthritis more effectively than conventional drug therapy, according to a study by German scientists. It might seem like a story from many centuries ago, but the news appears to be the result of a carefully controlled, very modern medical trial.


The study included 51 patients with severe arthritis-related knee pain. The 24 patients who had leeches applied to their joints reported an average reduction in pain from 53.5 to 19.3 on a standard scale used to measure pain. The reduction for those treated with diclofenac, a nonsteroidal anti-inflammatory drug (NSAID), was much less, from 51.5 to 42.4, according to the report from physicians at the Essen-Mitte Clinic in Essen, Germany.

The pain relief received from leech therapy wore out after one week, but "differences for function, stiffness and total symptoms remained significant for leech therapy until the end of the study," which lasted 30 days, the report says. There are many possible reasons for the beneficial results, says Dr. Gunther Spahn, a professor of internal and integrative medicine, who was a member of the study team.

"Leeches are a pharmaceutical company, injecting. . .many substances into the soft tissue," Spahn explains. "These substances may have an anti-swelling, anti-inflammatory and analgesic effect."


Dr. Marc C. Hochberg, professor of medicine at the University of Maryland School of Medicine, says, "I would hope it (leech therapy) would not be done until there is more data demonstrating safety and efficacy, especially in comparison with standard therapy."

A major problem with the study, he says, is that both groups of patients knew which treatment they were getting, which "raises concern about measurement bias," especially since the pain scores were based on patients' judgment.

A "more exciting" aspect of the study is that it might lead to better painkilling drugs based on an analysis of the molecules in leech saliva, Hochberg says.

Leeches had been used for centuries to get "the bad blood out," but the practice fell into disfavor by the 19th century. Today,leeches are used medically in this country, but on a very limited basis, according to Marie Bonazinga, president of Leeches USA Ltd., which sells them commercially.

You can learn about the medicinal leeches from the University of Michigan at http://animaldiversity.ummz.umich.edu.

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