ShortCuts-This Week in the Journals

January 28, 2008

800px-long_meadow_panorama_from_north_prospect_park_foggy_morning_jpg.pngCommentary by Henry Tran, MD

Old adage: just because it’s new doesn’t necessarily mean it’s better. The FDA approved the usage of drug-eluting stents (DES) in 2003 and these stents were quickly embraced by the cardiology community as a technological breakthrough in the treatment of coronary artery disease. It’s estimated that more than six million people worldwide have been implanted with a DES. In 2006, two studies created a lot of discussion by reporting an increased incidence of late stent thrombosis with DES with a high associated mortality. Two observational studies specifically examining DES were published this week in the NEJM.

One study by Hannan et al. compared the outcomes of DES versus coronary-artery bypass grafting (CABG) in a registry of patients from New York state. For multi-vessel disease, CABG was associated with significantly lower rates of death and of death or myocardial infarction (combined endpoint) compared to DES. This study also evaluated three high-risk subgroups (patients with diabetes, patients with LVEF <40, and age >80). In regard to patients with diabetes, contrary to the results of the BARI trial which randomized patient to CABG vs. PTCA, CABG did not have a statistically significant difference in adjusted mortality rates over DES. It should be noted that the BARI trial revascularized patients via angioplasty without the usage of stents. Perhaps there should be more examination of the outcomes of stenting in patients with diabetes.

Another study by Marroquin et al. compared outcomes of patients who were revascularized with either DES or bare metal stents. Aside from addressing the safety concerns of DES vs. bare metal stents, this is a very important study because it also examined the use of these stents in either approved or unapproved “off-label” situations. The FDA approved the use of DES based on the results in a highly selected trial population; however stents have been used in many “off-label” applications, i.e. lesions at vessel bifurcations, multi-vessel disease, etc. The authors found that off-label use is associated with worse outcomes when compared to standard usage. And while DES were used in a higher-risk patient population, the authors found no significant differences in the adjusted risk of death or myocardial infarction in patients with DES versus patients with bare-metal stents. Consistent with data from initial device trials, there was less need for revascularization with DES compared to bare-metal stents. However this study is limited by the short follow-up of only one year. It will be very important and powerful to see if the survival curves start separating as patients with DES discontinue dual anti-platelet therapy.

The association between obesity and insulin resistance is well known. Accumulating research has shown that obesity reduction through bariatic surgery can be an effective treatment for DM Type 2. JAMA reports a small unblinded, randomized trial that compared conventional medical/behavioral treatment of diabetes versus laparoscopic gastric banding plus medical/behavioral therapy in 60 obese pts with recent onset of diabetes mellitus. The primary endpoint of the study was the remission of diabetes, defined as a fasting blood glucose <126 mg/dL or Hemoglobin A1c< 6.2% without hypoglycemic treatments. Impressively, 22 pts (73%) of the surgical group achieved diabetes remission vs. 4pts (13%) in the medical group at 2 years. (NNT =1.6). This is the first time surgical therapy has been directly compared to bariatric surgery against medical therapy in a randomized trial. While these results may not be readily applied to the population of 19 million people with DM Type 2 in this country, certainly the promise of an effective remission of diabetes should spur a more robust trial to be conducted in a more hetergenous trial population. At one time peptic ulcer disease was one of the most common indications for surgery. The discovery of h. pylori and effective acid suppression treatments turned this surgical problem into a medical one. In the future will we think of obesity and diabetes as a surgical problem or will there be a more definitive medical treatment of this growing epidemic? (FYI, no article discussing diabetes can legally avoid using the phrase “growing epidemic.”)

Lastly, a  recent meta-analysis evaluated treatments for lower back pain, which is the blackbox of disease and complaint that internists frequently encounter. A Cochrane meta-analysis of 65 studies compared NSAIDs to placebo and acetaminophen. The meta-analysis found that NSAIDs have more side effects (mainly GI) than acetaminophen (RR 1.76). They found that for acute back pain, NSAIDs were only mildly more effective than placebo after a week of treatment (RR 1.19). Take home point: clinicians should recommend using NSAIDs for back pain only after acetaminophen has been tried.

Image courtesy of Wikimedia Commons