Weight loss studies are widely diverse, but they always show that weight loss is tough and weight loss maintenance is tougher still unless surgeons become involved. The Counterweight programme shows that significant weight loss across populations is achievable, but extremely difficult (Counterweight Project Team, 2008); other studies have shown barely any benefit to weight loss at all. It is in this context that the Look AHEAD (Action for Health in Diabetes) Research Group demonstrated much superior weight loss that was well maintained and translated into significant improvements in cardiovascular risk factors. It was halted for “futility” after nearly 10 years.
Apart from the Swedish Obese Subjects study, and the SCOUT (Sibutramine Cardiovascular Outcome) study of the withdrawn drug sibutramine, there has never been evidence that a specific weight management regime reduces mortality (Sjöström, 2008; Caterson et al, 2012). Studies such as the Diabetes Prevention Program (DPP) and Diabetes Prevention Study have done the next best thing: both showed a massive 58% reduction in the cumulative incidence of diabetes with apparently minor weight loss (DPP Research Group, 2002; Lindström, 2003). Others, such as the Paris Prospective Study (Fontbonne and Eschwège, 1991), linked obesity with cardiovascular mortality, allowing the sensible assumption that weight loss reduces outcomes.
Look AHEAD was, therefore, exciting and eagerly anticipated, being a large, long, well-designed, decently funded trial of weight loss, cardiometabolic parameters and mortality. For the first time, a study (summarised alongside) would answer the question whether there was any point in losing weight. It recruited >5000 overweight or obese individuals with diabetes over a predicted 13.5 years, and offered intensive calorie restriction plus physical activity versus conventional management (outcomes being cardiovascular mortality, non-fatal myocardial infarction/stroke or hospitalisation for angina).
The result was a resounding success: weight reduction of 8.6% at one year maintained at an unheard-of 6% at study end. This was particularly impressive given that spouse studies have shown that patients with diabetes lose approximately half as much weight as normoglycaemic patients on lifestyle regimes. Results also showed greater reductions in HbA1c, as well as improvements in fitness and all cardiovascular risk factors.
The use of antihypertensive agents, e.g. statins, and insulin was lower in the intervention group than the control group. Remarkably, after 9.6 years the study was prematurely halted for reasons of “futility”, demonstrating the gulf between the responsibility of researchers compared to clinicians. Pronouncing such impressive results as “futile” shows academics’ lack of respect and grasp of the efforts practitioners go to in order engage and motivate patients, and improve their glycaemic control and weight, alongside other cardiometabolic risk factors on a daily basis.
Some commentators point to the fact that a hypocaloric rather than a low-carbohydrate or Mediterranean diet was used as the intervention as the reason for the lower than expected outcomes, but what is more likely is the fact that cohesive care of co-existing risk factors today is so good that long duration studies now seem universally underpowered because their design is based on contemporary mortality rates prior to the study starting.
Other benefits included reductions in urinary incontinence, sleep apnoea and depression, and improvements in quality of life, physical functioning and mobility. Are these results futile?
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