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Glaucoma Treatment-latest updatesCreated:June 23, 2005Glaucoma therapeuticsStudy documents a shift in treatment patterns for glaucoma Prostaglandins account for close to half of all glaucoma prescriptions written in private practice in Australia, study finds. When it comes to glaucoma treatment patterns, new study results out of Australia suggest that the balance between medical and surgical management may be shifting. In a study published in 2004 in Clinical and Experimental Ophthalmology, Mark J. Walland, M.D., Melbourne, documented changing glaucoma treatment patterns in Australia from 1994 to 2003. Dr. Walland opted to launch the study based on his impressions that there had been a change in glaucoma management. “My own impression from clinical practice and also from my work in the public hospital system was that we just weren’t doing as many trabeculectomies any more,” Dr. Walland said. After reviewing Australian government data from 1994 to 2003, Dr. Walland determined that since the introduction of latanoprost (Xalatan, Pfizer, New York), travapost (Travatan, Alcon, Fort Worth, Texas), and bimatoprost (Lumigan, Allergan, Irvine, Calif.), there had been a steep rise not only in the prescription of prostaglandins, but in the total number of scripts. By 2003, the prostaglandins accounted for 48.9% of prescriptions written in private practice in Australia, out of a total of more than 1.6 million prescriptions issued for all types of topical glaucoma medications for the year. In Australia, surgeons are making far fewer blebs than they used to -- trabeculectomy surgery has sharply declined. Source: Mark J. Walland, M.D. “Over the decade, the usage of alpha-agonists and carbonic anhydrase inhibitors has also grown, and the beta-blocking agents have held their ground,” Dr. Walland said. “As a result, there has been a 73% rise in the total number of prescriptions written, from approximately 1.9 million in 1994 to about 3.3 million in 2003. Meanwhile, the rates of laser trabeculoplasty and trabeculectomy surgery have sharply declined. “In the decade that was reported, there was a decrease of 60% in our rates of both trabeculoplasty and primary trabeculectomy surgery,” Dr. Walland said. The number of primary trabeculectomies plummeted in Australia over the 10-year study period. Source: Mark J. Walland, M.D. The numbers show that there is a trend toward medical management of glaucoma, Dr. Walland said. “The prostaglandins are at least a part of that trend,” he said. “I suspect that the reason for the rise in the total number of scripts is that there’s just this impression now that you can get control of glaucoma with medication and you shouldn’t need surgery, or you need it much less frequently.” Currently, there are a dozen different glaucoma preparations to choose from across five classes of medication. “Part of my impression about the decreased rates of surgery was that people were trying each of the various classes before they embraced surgery,” Dr. Walland said. There are several different ramifications resulting from the shift. “From a patient’s point of view, we haven’t actually proven or shown in any study that their glaucoma is as well controlled now as it was in the mid 1990s,” Dr. Walland said. One key assumption often made is that if pressure can be lowered by whatever means, practitioners will have equal control of glaucoma. However, this assumption is an unproven one. While some evidence suggests that some medications may offer a neuroprotective effect, there’s also an understanding that surgery is the best way to remove diurnal variation in IOP. “It’s likely that a subgroup of the patients who continue to deteriorate despite medical therapy were actually getting worse because of a diurnal variation that just wasn’t detected,” Dr. Walland said. “Surgery manages to flatten that variation and may still be the preferred way to go.” Dr. Walland also determined that the total cost to the government as a result of the shift to medications was a 250% to 260% increase in subsidies. So far, the government hasn’t inquired about why this is occurring, but that may change. “They may at some stage ask to see evidence to the effect that patient care is improved by this increased expenditure,” he said. Since the study, Dr. Walland said that trabeculectomy rates may now be climbing again. “I suspect that what’s now going on is that the patients have now been tried on all the various classes and there’s still a subgroup of patients who won’t be controlled medically,” Dr. Walland said. “Those patients are now are coming to surgery.” Parallel American shiftReay H. Brown, M.D., in private practice, Atlanta, said that the shift from surgery to medication holds true in the United States.“It’s the same thing that we’re seeing in this country,” he said. There is always an interval that follows the introduction of new medications that results in a temporary surgical decline. “You go through a period where you’re trying all these new treatments, so there’s a period of time where surgery is at least delayed,” Dr. Brown said. He recalls some research he did as a resident at Johns Hopkins University, Baltimore, on what the introduction of laser trabeculoplasty did to the number of surgery cases at the institution during that time. “What we found was that it eliminated all surgery,” he said. “There were no cases done for one or two years on the Johns Hopkins residence service, while before that there were about 18 to 20 cases.” Within three years, however, there were more surgical cases being done than ever before. Like the current shift from surgery to medication with the current introduction of prostaglandins, a similar shift occurred in the past with the introduction of timolol (various manufacturers), said Michael S. Berlin, M.D., director, Glaucoma Institute of Beverly Hills, and professor of clinical ophthalmology, Jules Stein Eye Institute, University of California at Los Angeles. “What’s happening now is just like the inverse curve with the introduction of timolol — medication use increased and surgical use decreased,” Dr. Berlin said. “Over time, however, when it became apparent that the medications still didn’t always prevent further vision loss, surgical interest was renewed.” Dr. Brown said that the surgical procedure, which has stayed the same for 100 years, is the weak link. “We’re stuck with an operation that takes too long, has too much follow-up, patients don’t like it, and it too often doesn’t work,” he said. “There are so many negatives that people will try anything — they’ll put patients on five different medications, they’ll have red eyes, and they just won’t think about surgery.” Ultimately, newer laser procedures such as selective laser trabeculoplasty (SLT), which was approved in 2002, could turn the tide, said Dr. Berlin. If it is determined that the SLT procedure can effectively be repeated and continue to lower pressure, this could shift parameters away from medications back to surgery. Also, the evolving kinder, gentler Schlemm’s canal procedures — such as excimer laser trabeculostomy, the development of the new stents and drainage ducts into the canal, which yield, effective, long-term pressure lowering effects with less trauma to the eye — require less post-op medical monitoring, and are less debilitating to the patient. These procedures will drive a larger surgical population and decrease medication use, putting glaucoma management back in the hands of a skilled surgeon rather than the patient, Dr. Berlin said. Editors’ note: Dr. Walland has been a consultant for Pfizer, and a collaborative researcher for Allergan. Dr. Brown is a consultant for GMP Companies Inc. (Fort Lauderdale, Fla.) Dr. Berlin is a speaker for Alcon (Fort Worth, Texas), Lumenis (New York), Merck (Whitehouse Station, N.J.), and Santen (Napa, Calif.). Contact Information Berlin: 310-855-1112, berlin@ucla.edu Brown: 404-252-1194, reaymary@comcast.net Walland: 61-3-9417-1079, mwalland@clyde.its.unimelb.edu.au |