Research news and notes

1. Which diet is better? 

The scourge of obesity is so widespread in the United States that it is no longer the problem of internists or the business of bariatric surgeons alone. All aspects of patient care are involved. Diet and exercise are the basic recommendations for most of the obese patients, but which diet is better? Is the classic low-fat diet the answer; or will its apparent opposite, the high-protein, high-fat, and low-carbohydrate Atkins diet, prove superior? The March 7 issue of the Journal of the American Medical Association [1] provides one of the few available direct randomized comparisons between various diets. Four different diets with different levels of carbohydrate intake were compared in 311 women with body mass index of 27 to 40. The diets included Zone, LEARN, Ornish, and Atkins. The primary outcome was weight loss at 12 months. Patients were assessed at 0, 2, 6, and 12 months for metabolic markers, including lipid profile (low-density lipoprotein, high-density lipoprotein, non–high-density lipoprotein cholesterol, and triglyceride levels), percentage of body fat, waist-hip ratio, fasting insulin and glucose levels, and blood pressure. Atkins dieters fared significantly better than all others, losing 4.7 kg on the average and having similar or better metabolic profiles at the 12-month end point. All the others lost around 2 kg on the average, without significant differences between them. This is an important evidence that the ubiquitous recommendation to replace fat in the diet with carbohydrates may not be an effective way to diet. Looks like low-carbohydrate diet is here to stay.

2. What we all know for sure—it is not necessarily so 

The exact method of cardiopulmonary resuscitation (CPR) by someone witnessing a cardiac arrest has been modified over the years, but the principles remain the same. Chest compressions are combined with mouth-to-mouth ventilation for the best chance of saving the victim. However, mouth-to-mouth ventilation is a major problem for most bystanders. Is doing only chest compressions valuable? In a recent issue of The Lancet, a prospective multicenter observation study evaluated the outcomes of 4068 adults who had out-of-hospital cardiac arrest [3]. Participating paramedic teams assessed the technique of bystander resuscitation upon arrival at the scene. The end point was favorable neurological outcome 30 days after the arrest. Having any resuscitation attempt by anybody resulted in a better outcome than no attempts before the paramedics arrived—5% vs 2.2%. So far, no surprises. Upon direct comparison, cardiac-only resuscitation was much better than conventional CPR—6.2% favorable outcome compared with 3.1% for apnea, 19.4% vs 11.2% for shockable rhythm, and 10.1% vs 5.1% for resuscitation that started within 4 minutes of the onset of the event. The results do make sense. To try and ventilate the patient, the rescuer has to stop chest compressions. Proper ventilation is technically difficult. This study does not prove that CPR performed perfectly by an instructor is not better or at least as good as chest compressions. However, in the real world, we should probably stop trying to insist on CPR. Possibly, some bystanders who may now avoid CPR would be more readily available for cardiac-only resuscitation. The accepted paradigm will shift again—what we all knew for sure may not be so.

3. Do not get a heart attack on a weekend 

Hospitals, like any other organization, work on a different schedule on weekends. Fewer physicians, technicians, operating room, and other personnel are available. Does it affect patient outcomes? I am not sure everyone would want to know the answer. Kostis et al asked and answered this question in a recent article in the New England Journal of Medicine [2]. They examined mortality in patients admitted in New Jersey from 1987 to 2002. They used a large database called the Myocardial Infarction Data Acquisition System. To account for changing practices and technology, they divided the time into 4-year periods. Invasive procedures advanced and improved significantly over the years, as did the patient outcomes. For the period 1999-2002, covering 59786 admissions, a new pattern appeared. The patients admitted on weekends had fewer invasive procedures and had worse outcome compared with those admitted on weekdays. The difference was relatively small—1% total difference in mortality—but it appeared on day 1 and persisted at 1 year of follow-up. Given the large number of patients involved, the total additional mortality of weekend patients accounted for hundreds of deaths. The patients admitted on weekends benefited less from the latest advances, and their outcomes were accordingly more like those in earlier years.

There are different ways to interpret the results. Positive spin is possible—by introducing new capabilities during weekdays, the hospitals and practitioners improved the outcome for most of the patients compared with previous years. However, patients and their families may not see it this way. Neither should we. This study is a demonstration of the effect of lack of availability of advanced specialty services on a particular day at a particular hospital. How many lives and how much neurological function is lost when a neurosurgeon is not available to cover a hospital that still accepts patients with trauma and other acute conditions? Our societies may want to promote such a study.