By: Norman Bauman for Wounds1
When doctors want to use the best treatments, they are faced with a paradox. Modern medical science has come up with new, promising treatments. But modern medical science has also come up with the idea of evidence-based medicine. Some new treatments work, and some don't. Evidence-based medicine is the practice of evaluating the scientific evidence behind each treatment.
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Medical treatments may be supported by strong evidence, weak evidence, or habit and custom. Ask your doctor whether a treatment is evidence-based medicine.
If a medical treatment has been demonstrated to be effective with randomized, controlled studies, we know it works.
If there are no randomized, controlled studies, it's still experimental and we don't know for sure whether it works.
The newest treatments often don't have randomized, controlled studies.
The best evidence for a medical treatment is a consensus statement by many doctors and medical societies.
Doctors still use many common treatments even though they have no randomized, controlled studies, because they work in some patients.
If foot ulcers are caused by a blocked artery in the leg, then the most successful treatment available is surgery to repair the blockage.
There is strong evidence that compression stockings and bandages heal venous leg ulcers.
You can find out if there is strong scientific evidence for a treatment at http://www.cochrane.org and (for wounds) at http://www.woundheal.org. |
"The best evidence that any medical therapy is worthwhile," said David L. Steed, Jr., M.D, Professor of Surgery, University of Pittsburgh, "is considered to be a randomized prospective double-blind placebo-controlled trial." In such a trial, patients are randomly divided into a treatment and no-treatment group. Traditionally, the treatment group gets a pill, and the no-treatment group gets a sugar pill. Neither the patients nor the doctors who are treating them know who is getting the treatment. If the treatment group does better, that's the best evidence that the treatment works.
But randomized controlled trials aren't always possible. "The medical community also accepts, to a lesser degree, clinical series, retrospective series reviews, and animal studies if the weight of evidence is overwhelming." Instead of randomizing patients beforehand, doctors simply review their records to see how patients turned out. This is much easier, but can also give the wrong conclusion.
At medical conferences and in medical journals, doctors like to go through the treatments for different diseases and see which ones have the best evidence, which is large randomized controlled studies; which ones have weaker evidence, which is small or non-controlled studies, and which treatments have no good evidence at all. Doctors often refer to the evidence as Level I, Level II, or Level III. As new treatments are studied, they start out with weak evidence, and over the years accumulate better evidence, to prove eventually that they work – or don't work.
Leg ulcers
At the VEITHsymposiumâ„¢ on vascular surgery in New York, Dr. Steed reviewed some of the common treatments for wounds and skin ulcers and summarized the strength of evidence for each.
Leg ulcers often don't heal because the arteries to the leg are blocked and narrowed with atherosclerosis or other obstructive conditions. If the skin doesn't get enough oxygen, the ulcer can't heal, and it sometimes progresses to gangrene and amputation. Vascular surgeons can often restore the blood supply to the leg by using bypass grafts to go around the obstruction, or by threading a thin balloon into the artery to open it up with air pressure. "Revascularization of the ischemic wound is, unquestionably, the most successful form of therapy in the wound healing area," said Dr. Steed.
For diabetic foot wounds, pressure offloading and topical growth factors are "clearly of benefit," said Dr. Steed. Screening and referral to wound clinics, systemic hyperbaric oxygen therapy, and living skin equivalents are "probably beneficial," he said. "There is less convincing evidence for therapeutic footware, although almost all would recommend it," he said.
For venous leg ulcers, said Dr. Steed, compression bandages and stockings are "clearly indicated" for controlling venous hypertension, which is the initial cause of the ulcers. This was supported by Level I evidence. Living skin equivalents and superficial vein surgery are "probably of benefit," he said. "Most of the other treatments we use have varying degrees of support in the literature, including enzymatic debriding agents, specialty dressings, laser therapy, and topical antibiotic therapy," said Dr. Steed. There may not be conclusive proof that they work. "For any individual patient, however, one of these therapies may make a difference."
Panels of doctors create guidelines to collect the evidence for different treatments, and to recommend the best treatments. The Wound Healing Society recently created guidelines for treating the major ulcer types, said Dr. Steed. They are available free at the Wound Healing Society's web site, .
