EDMONTON, ALBERTA--Bloodsucking leeches relieve the pain of thumb arthritis more effectively and for a longer period of time than the conventional painkilling ointment, according to new clinical trial results. The findings, presented here yesterday at the North American Research Conference on Complementary and Integrative Medicine, may move leech treatment one large wriggle closer to the mainstream of medicine.
Osteoarthritis of the thumb afflicts millions of people, causing joint pain debilitating enough to keep them from opening jars, writing notes, and gripping anything tightly. Doctors usually prescribe painkilling pills, injections, or ointments, but none of the treatments work well. Internist Gustav Dobos of the University of Essen in Germany, and his colleagues had successfully treated patients' arthritic knees with leeches before. The worms inject a blood-thinning chemical called hirudin and several substances that fight inflammation--components that keep a prey's blood flowing in the wild (ScienceNOW, 6 February 1998).
To see whether the bloodsuckers could also ease thumb-joint pain, Dobos's team randomly assigned 32 women with a median age of 64 to one of two groups. Sixteen of the women applied a commonly used painkilling ointment called dicyclofenac twice a day for 30 days. The others were treated once with two or three leeches, which were allowed to latch onto the soft tissue on or near the joint at the base of the thumb. When the patients returned for follow-up visits, the German team had them use a standardized test to rate their pain on a scale of 0 to 100 while their hands were at rest or while they performed various tasks, such as moving their fingers or gripping a ball.
A week after they were treated, leeched patients rated their pain less than half as intense as those who received ointment, and after 2 months, their pain was still significantly less than the ointment-treated group reported. In addition, the leech patients' grip strength, as measured by their grip on a ball that measures force, had improved by 36% 2 months after the treatment. Ointment patients only experienced a 7% increase in grip strength. Finally, arm and hand disability in the leech group decreased by 47% after 2 months compared to just a 4% improvement for the ointment group.
The successful leech therapy is "really exciting because it's a new treatment for a condition that's very difficult to treat," says internist Roman Huber of the University of Freiburg, Germany. What's more, he says, "it's astonishing that the effect lasts so long."