I have one problem with your otherwise excellent article, “Diabetic dyslipidemia: A practical guide to therapy,”1 in the June issue. In a remark concerning Vytorin, the authors state: “This combination has been questioned recently, as the addition of ezetimibe provided no improvement in surrogate markers.” I believe this sentence, which references a JAMA commentary by Philip Greenland and Donald Lloyd-Jones,2 is inaccurate and misleading.
I am not here to praise or bury Caesar, but I agree with Drs. Greenland’s and Lloyd-Jones’ interpretation of the ENHANCE trial and the lessons to be learned by the media, research scientists, and pharmaceutical firms. ENHANCE found statistically significant benefits in several cardiovascular surrogate markers (low-density lipoprotein, total cholesterol, and C-reactive protein) from the combination of agents in Vytorin (ezetimibe and simvastatin); it simply failed to find a statistical difference in carotid intimal thickness. The mistake repeated by the authors was to equate the failure to determine a difference with proof that no difference exists.
Oliver T. Willard, MD, ABFM
Piedmont Health Group
Greenwood, SC
owillard@phgrp.com
The authors of the June cover story on diabetic dyslipidemia do a nice job of describing the lipid studies, but draw some conclusions that several national organizations and authorities in the field do not support.
I do not agree that data suggesting low-density lipoprotein (LDL) <70 mg/dL is controversial. A recent consensus statement by the American Diabetes Association and the American College of Cardiology1 reviews the existing literature and recommends LDL <70 mg/dL as a goal for diabetic patients with 1 additional risk factor.
Nor do I agree that patients whose aspartate aminotransferase/alanine aminotransferase (AST/ALT) is 3 times the upper limit of normal (ULN) are not eligible for lipid-lowering therapy. If all patients with diabetes had liver biopsies, most would be found to have fatty livers—but not all would manifest this condition with elevated liver enzymes. Many such patients receive lipid-lowering therapy, with no adverse effect. After an extensive literature review, the National Lipid Association (NLA) Statin Safety Task Force determined that statins are safe when enzymes are >3 times ULN. The task force has published extensive guidelines2 that review the subject and offer helpful recommendations. Among them is the suggestion that routine monitoring of liver enzymes not be done. The issue is also addressed on the NLA web site (http://www.lipid.org).
Granted, consensus statements are a different level of evidence than the studies the authors cite. In fairness, however, consensus statements and the articles that support them should be included in a review so readers have all the information they need to make clinical decisions.
Edward Shahady, MD
Diplomate, American Board of Family Medicine
Diplomate, American Board of Clinical Lipidology
Diabetes Master Clinician Program
Florida Academy Family Physicians Foundation
Fernandina Beach, FL
eshahady@att.net