Looking Back at Look AHEAD
Last week, the US National Institutes of Health (NIH) announced the discontinuation of the intensive diet and lifestyle interventions in the Look AHEAD (Action for Health in Diabetes) study. This study, now in its eleventh year, was designed to compare the effects of an intensive diet and lifestyle program designed to promote and sustain weight loss versus ‘usual care’ on the prevention of heart attacks, strokes and cardiovascular deaths in individuals with long-standing type 2 diabetes. The study was conducted at 16 centers across the United States included 5,145 people who were 45 to 76 years old when they enrolled in the study. Sixty percent of participants were women. Participants in the intervention group lost more than 8% of their initial body weight after one year of intervention and maintained an average weight loss of nearly 5 percent at four years. This reduction in body weight was accompanied by significant improvements in glycemic control and numerous other health benefits (e.g. decreased sleep apnea, improved mobility and quality of life). However, given a remarkably low incidence of ‘hard’ endpoints in both the interventions and control groups, it became evident the the study would stand little chance of demonstrating superiority of the lifestyle intervention in terms of preventing cardiovascular complications. These results are perhaps not all that surprising, given that recent pharmacological studies in patients with type 2 diabetes have also failed to show a significant reduction in cardiovascular deaths. Moreover, readers may be aware that even with the substantially greater reduction in body weigh with bariatric surgery, the Swedish Obesity Surgery study, took over 13 years to demonstrate a barely significant reduction in myocardial infarcts (but not deaths!) in patients with type 2 diabetes. In hindsight, hoping for a greater impact with diet and exercise than even that seen with bariatric surgery would seem rather optimistic (to be fair, the surgical data were not available at the time this study was planned). Nevertheless, according to the recommendations of the Data Monitoring Board, the study should be continued (without the intervention) to determine the long-term outcomes in the participants. While the results of this study are certainly disappointing to the researchers involved, they do provide important lessons for designing future trials of obesity treatments in patients with type 2 diabetes. Not only may future studies have to enrol a substantially greater number of participants but such studies may also need to substantially… Read More »
Weekend Roundup, October 19, 2012
As not everyone may have a chance during the week to read every post, here’s a roundup of last week’s posts: Early Bird Registration Opens for the Canadian Obesity Summit, Vancouver, May 1-4, 2013 More of the Same Leads to More of the Same CMPA Warns Canadian Surgeons About Risks of Bariatric Surgery Does Short-Term Overeating Make You Hungrier? Pelvic Radiographic Imaging in Obese Women Incidentally, pre-sales of tickets for the “Stop Being a Yo-Yo: a Lighter Look at the Ups and Downs of Weight Loss” events in St. Alberts (Nov 5) and Mill Woods (Nov 14) are remarkably brisk – just over 50% of tickets are already sold – so reserve your tickets before they are gone! Have a great Sunday! (or what is left of it) AMS Edmonton, Alberta
Hindsight: Fat Distribution, Not BMI, Determines Cardiovascular Risk
In 2005, while still at McMaster University, I had the privilege of being involved in a publication that is now, by any standard, already a ‘classic’ in the field of obesity. The paper, published in Lancet, compares BMI (as a measure of obesity) to wasit-to-hip ration (as a measure of fat distribution) as a predictor of myocardial infarction in 27,000 participants from 52 countries. In this standardised case-control study (INTERHEART), with 12,461 cases and 14,637 controls, we found that although BMI showed a modest and graded association with myocardial infarction (OR 1.44), this relationship was was substantially reduced after adjustment for waist-to-hip ratio (1.12), and non-significant after adjustment for other risk factors (0.98). In contrast, we found that for waist-to-hip ratio, the odds ratios for every successive quintile were significantly greater than that of the previous one (2nd quintile: 1.15; 3rd quintile: 1.39; 4th quintile: 1.90; and 5th quintiles: 2.52 [adjusted for age, sex, region, and smoking]). In fact, both waist (adjusted OR 1.77) and hip (0.73) circumferences were highly significant after adjustment for BMI. Finally, the population-attributable risks of myocardial infarction for increased waist-to-hip ratio in the top two quintiles was 24.3% compared with only 7.7% for the top two quintiles of BMI. For anyone still believing that BMI is even a weak indicator of cardiovascular risk, this study should have long dispelled any such notions – increased BMI (alone) is simply not a good measure of cardiovascular risk – period! Despite this, BMI continues to appear in guidelines, continues to be used as indications for treatments (e.g. bariatric surgery), and continues to be the basis for predictions on the health impact of the obesity epidemic. Some people just take longer to learn than others. Not surprisingly, this paper has so far been cited well over 1300 times. AMS Edmonton, Alberta
CMPA Warns Canadian Surgeons About Risks of Bariatric Surgery
Regular readers will note that I fully support the use of bariatric surgery as a treatment for patients presenting with severe obesity, especially when these patients present with obesity related complications (EOSS Stage 2 and higher). However, as regular readers will also note, I am the first to remind clinicians (and my patients) that surgery is surgery and that even in the best hands, serious life-threatening complications can occur. In a recent issue of its journal, the Canadian Medical Protective Association (CMPA), which provides mandatory medical liability protection to the majority of Canadian physicians, warns that surgeons and physicians involved in caring for bariatric surgical patients should be fully aware of the medico-legal issues regarding bariatric care. As the authors of the article note: “Between 2006 and 2011, the CMPA had 27 medico-legal cases relating to bariatric surgery, 21 of which were closed. A review of the closed cases showed the main allegations from patients were that consent discussions were lacking and histories were inadequate.” The article lists in detail the problems that were identified by the experts reviewing these cases: Pre-Surgical Issues: – Failure to evaluate the patient, discuss the risks including the alternatives to surgery, and document the consent discussion. – Failure to rule out pregnancy. – Failure to order prophylactic antibiotics. – Not requesting the assistance of a second surgeon to help with a laparotomy for a complex patient with peritonitis. Intra-Surgical Issues: – Internal injuries (e.g. to stomach and small bowel) sustained during a laparoscopic approach from manipulations of the organs; often these were diagnosed post-operatively when patients became symptomatic with nausea, vomiting, fever, or abdominal pain – Inadequate attempts to locate and repair the source of a gastric leak. – Retention of a large malleable retractor, discovered 2 years after the operation; instrument counts were not done as per hospital policy. – Failure to convert from a laparoscopic to an open procedure when experiencing significant difficulty identifying anatomical structures. – Misconstruction of the small bowel limbs during Roux-en-Y gastric bypass. Post-Operative Issues: – Delayed recognition of respiratory distress and the need for treatment. – Premature hospital discharge of a patient with fever and erythema at the surgical incision site with delayed recognition of the underlying wound infection and dehiscence; the nursing care was also criticized for inadequate postoperative monitoring of vital signs and wound assessment. – Lack of documentation of a patient’s condition on discharge and inadequate discharge instructions given to the patient and family. – Failure to investigate a patient’s complaint of abdominal pain, nausea, and vomiting when readmitted a few days after surgery. –… Read More »
Pelvic Radiographic Imaging in Obese Women
Readers of these pages are probably well aware that increasing body size poses important challenges for many areas of health care. Not least, when it comes to diagnostic imaging. A paper by Phyllis Glanc and colleagues from the University of Toronto, published in RadioGraphics provides a succinct overview of some of these challenges when it comes to radiographic imaging of the pelvis in obese women. As the authors point out, “Obesity can contribute to missed diagnoses, nondiagnostic results of imaging studies, imaging examination cancellation because of weight or girth restrictions, scheduling of inappropriate examinations, and increased radiation dose exposure.” Furthermore, “The utility of the clinical examination is often limited in the obese woman, which results in an even greater reliance on imaging.” Thus, “Recognition of equipment limitations, imaging artifacts, optimization techniques, and appropriateness of modality choices is critical to providing good patient care.” Although quite technical (as one would expect), this article is probably a worthwhile read for anyone who orders or performs pelvic exams in obese women. AMS Edmonton, Alberta photo credit: EUSKALANATO via photopin cc Glanc P, O’Hayon BE, Singh DK, Bokhari SA, & Maxwell CV (2012). Challenges of pelvic imaging in obese women. Radiographics : a review publication of the Radiological Society of North America, Inc, 32 (6), 1839-62 PMID: 23065172 .
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