Tuesday, February 16, 2010

Weight Loss, Nutrition, Low Salt, Low Sugar

This blog was stimulated by the recent surge to have government endorse/require lower salt in the diet. There is, of course, no direct evidence that a low salt diet prolongs life. In the recommendations, lowering salt in the diet is taken as a surrogate for lowering blood pressure. It is assumed that lowering the amount of salt in the diet by 3 grams/day will lower systolic blood pressure between 3.5 and 5.5 mm; no estimate is given for the effect on diastolic blood pressure (is there any?). It is claimed that this will reduce death by heart attacks and other problems.

High blood pressure is a demonstrated risk (i.e. there a correlation, but an 0.80 correlation is a 0.8x0.8 or 64% estimate) for strokes, hypertensive heart disease, and abdominal aortic aneurysms (the latter in male smokers). However, every study of lowering blood pressure (usually by diuretics) only shows a reduction in the risk of strokes; there is NO demonstrated reduction in mortality or hypertensive heart disease. I should also mention that reduction of blood pressure by beta-blockers alone has shown no reduction in any risk of stroke or heart attack. In addition, there has been no prospective study to see if lowering the amount of salt in the diet has any injurious effect, and a lot of medicine is counter-intuitive. I recall a study that lowering the salt in the diet INcreases the risk for heart failure, but who really knows?

A related dietary question deals with lowering the amount of sugar in the diet (?by taxing sodas). I pause here to remind my lay readers that just because diabetes is evidenced by elevated blood sugar, this does NOT mean that increasing the amount of sugar in your diet causes diabetes, assuming you gain no weight. And we will also ignore the white lab rat study that shows that if we keep lab rats 30% below their IBW (and who determines the Ideal Body Weight for a lab rat?) they live longer. The flip side is the recent studies that demonstrate that overweight adult humans (BMI 26-29) have an increased chance of surviving a heart attack.

Now let us assume that we wish to lose weight. What is the most efficient and surest way to do this? (Remember that when you lose weight as an adult, your fat cells shrink, and get smaller and have a smaller net surface area for metabolism.) Of course, the obvious method is to eat less. No one was overweight in a concentration camp. The lap-band surgery shrinks the functioning volume of your stomach, so you can't ingest many calories, and again you lose weight, and usually cure your diabetes as well. Anorectics have absolutely no problem in losing weight. In another vein,liposuction sucks the fat cells away from your body,and these cells can never increase in size again.

But the brain demands homeostasis, and strives to keep your body parameters as constant as possible. Most people's weight varies very little from year to year. All nutritionists agree that 3500 calories = 1 pound. If you divide 3500 by 350 days, you find that you have to micromanage your food intake to plus or minus 10 calories a day to keep your weight constant for the year. Not even the most dedicated fanatic can do this. Obviously, the brain has a mechanism to raise or lower your metabolism to keep your weight constant, sort of a feedback mechanism, which has nothing to do with leptin. This metabolic/mass inertia is what makes it equally difficult to gain or lose a lot of weight. In fact studies have shown that when you gain weight, your metabolism increases, and when you lose weight, your metabolism decreases, in a true negative feedback manner, which is why most dieters hit intermittent weight plateaus.

In order to lose weight, you must feel good about yourself, and be relatively happy and free from anger. Food was the first pleasure, given to you by your mother. It is very difficult to deny yourself this pleasure if you are not "in a good place". If you are mentally at peace, then you can walk around hungry without feeling (emotionally) deprived. You can be satisfied by the flavor of half a chocolate chip cookie rather than a whole box of Mallomars. So losing weight is not a matter of pure will-power, but rather a matter of not being too out of rhythm with the world and ego-dystonic. This is not to say that all overweight people are neurotic. Many are very happy with themselves, and see no need to change their body habitus. Your self-image is everything to you, and this is what we all rely on and judge ourselves by. This is why I don't think special diets are the answer. We all eat the way we like, and no one does Weight Watchers forever. The answer is always portion control. Why torture yourself by eating foods you don't like , instead of simply eating less of the foods you do like?

Let me close by saying eating "healthy" food is less important than eating less and losing weight. We know very little about nutrition. When I went to school as a child, the food pyramid was the exact inversion of what it is now. We don't even know (i.e. have good evidence) if the biggest meal of the day should be breakfast, lunch, or dinner. Should we have one large meal a day or six small ones. For every study, there is a counter-study. Do lefties live longer than righties? Do short people live longer than tall people? Why does overall health correlate so strongly with economic position in life? Maybe we all would be healthier if everyone were a millionaire? Any time any person or authority tries to tell you that something is "good" for you, or "good for your health" always ask the same question we asked reflexively in physics and on hospital rounds: "Do you have a published article to support that opinion?".

Saturday, February 6, 2010

Electronic Medical Records

There have been many articles published about the benefits of electronic medical records. The US gov't has appropriated millions of dollars to aid in their development and adoption. The claim is that the adoption of such systems will save money by reducing the number of duplicated tests and also reduce patient mortality and morbidity because fewer errors will be made.

I will leave aside the question of the possible (unproven as yet) benefits of computer-generated hospital records and notes. I will note,however, that computerized hospital notes and orders use up more of a doctor's time, and that is the one dimension we already have too little of. It used to take me 5 minutes to admit a patient with pen and paper. Now it takes at least 25 minutes on a computer, in part because of "mission creep". By mission creep I allude for instance to the U.S. Census, which is mandated by the U.S. Constitution to do a head count every 10 years to re-apportion U.S. Congressional districts among the states, but now also requires you to tell the government how many bathrooms, bedrooms, and telephones you have, among other details. And when the computer crashes, all the residents are helpless.

I admit to two hospitals. In one of them, I cannot even admit a patient unless I answer the question: should the patient I am admitting have a flu and pneumonia vaccine at discharge (and there is no place to indicate that the patient refuses). In the other hospital (and only God knows why) they ask for the birth date of the admitting doctor. This information can't possibly help the patient, but someone wants the information. They even set up the answer matrix so that 00-00-0000 does not work.So now most of the doctors were born on 11-11-1911, because that is the easiest number to write that the computer will accept.

I am also concerned because not once in the past 5 years has a nurse called me from the ward to ask if my drug order was correct. The order goes by the computer to the pharmacy dept., who delivers it pre-labeled to the floor. The nurses seem to think that a computer-generated label must be correct, and besides, the pharmacy filled it. Of course the pharmacologist does not know the patient nearly as well as the nurse does, but it is efficient! I don't even want to discuss my reaction when I ask an intern for a patient's Hct. , and I am told that it isn't in the computer yet. It never occurs to them that the number is generated by the hematology laboratory, and you can call them up for the result.

Now let's look at electronic medical records, and their benefit for the patient. When I started practice, I used to give all my patients a photo-reduced copy of their EKG to keep with them , because when a patient hits the ER with chest pain, the doctor certainly wants to know what the previous EKG looked like. I found that fewer than 10% of patients carried the copy with them, so I stopped this practice.

Now a doctor's medical record system is supposed to be compliant with and interactive with the hospital system. This requires you to be HIPAA compliant which means the changing of your hospital password every 90 days, or else you cannot log on to the hospital computer. How in the world can two hospital computers exchange data? I can't imagine changing your password every 90 days for every hospital in the US, and the SmartCard still requires a password.

I also know that every doctor wants to review Xrays and MRI results personally before surgery, etc. So even if I have a transmitted electronic report about the result of an MRI, I would want to repeat it if the patient's treatment depended on it. This also holds true for cardiac echoes, stress tests, cardiac angiograms,etc. If you were a patient, wouldn't you want your doctor to personally review a study before operating? You also would not trust the result of a technically difficult lab test (e.g. N-terminal parathyroid hormone) unless you had total faith in the lab, and therefore you would probably repeat the test. And if different labs with different techniques have different normal ranges, this complicates matters still further. Similarly, where cancer is concerned, the pathologist and oncologist will want to review the biopsy slides personally, rather than rely on a written report.

All the above can be summarized by saying that no doctor would depend on a written report alone, but would want to see the actual data. If details are needed in the ER about a patient, then the ER doctor will probably communicate with the family doctor for information that is not in the computer system (e.g. the patient uses cocaine, is bisexual, etc.) because no computer system is totally secure. There is always critical data about a patient that is known very well by the family doctor but never makes it into the chart because of its sensitive nature. I would never write down in an office chart that a patient hates his wife or is having an affair if I know the wife has legal access to the chart, or vice versa. I am not being paranoid about the non-security of data in the hospital system, because in the last 2 years I have received communications from 3 Veteran's Hospitals that their information systems have been hacked.

I yield to no one in agreeing that computers are terrific for transferring information. What concerns me is the uncritical acceptance of information on a computer, and where the paper backup is when the system crashes. When patient lives are at stake, there must be accessible backup. As I recall, a few months ago LAX had to divert planes for 3 hours because of a malfunction in the computer program that linked their radar systems. There have also been recent articles on radiation overdoses received by patients because the technicians did not understand the intricacies of computer-operated radiation beams. And with a typical automobile having 30 computers with thousands of lines of code, it's a miracle that there aren't more recalls.

Let me close with the following anecdote (and I repeat that I am not a Luddite, and was an early fan of Wylbur): "Ladies and Gentlemen, welcome to the first fully automatic transcontinental airplane ride that is fully operated by onboard computers. We have 3 computers, and therefore double redundancy for safety. This system has been tested thousands of times. Relax as we take off, and be assured that absolutely nothing can go wrong, go wrong, go wrong, go wrong, go wrong,....."