Friday, June 29, 2012

Low Carb Diet vs Heart Disease in Women

Anyone remember the tagline for 1978's Jaws 2?  "Just when you thought it was safe to go back in the water . . ."  Well, after yesterday's small short study of low carb vs low glycemic index vs low fat diets, all seemed well in nutrition-land, as much as one can expect from small short studies.  That is, until Dr. Dean D pointed out a study released almost contemporaneously in BMJ which concluded that low carb diet was associated w/heart disease.

More specifically, the authors studied 43,396 Swedish women, 30-49yo @ baseline & free of heart disease, and followed for close to 16yrs.  Decrease in carbohydrate consumption, increase in protein consumption, and increase in low carb:high protein score were all statistically significantly associated with increase risk of incident (initial) cardiovascular disease.

Granted, this isn't a randomized controlled trial able to demonstrate cause & effect.  But given the numbers & duration, it's certainly worrisome to recommend low carb diet as a lifestyle, especially if you're a youngish Swedish female.





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Thursday, June 28, 2012

Energy Expenditure: Low Carb vs Low Glycemic vs Low Fat Diets

As you know, I tend to be a lumper rather than a splitter.  I look for common themes rather than unique storylines.  Along those lines, I view low carb & low glycemic index diets as variations on a theme:  less than typical carbohydrate consumption.  But a study published yesterday in JAMA suggests that low carb diet results in less reduction in resting energy expenditure (REE) & total energy expenditure (TEE) compared to low glycemic diet which in turn has less reduction in REE & TEE compared to low fat diet.

The authors arrived at their conclusion via a very clever crossover study in which each of 21 overweight or obese adult avg 30yo avg body mass index 34.4kg/m2 served as his/her own control.  In other words, over the course of 12 weeks, the subjects consumed an isocaloric diet of various composition for 4 weeks in a randomized fashion.  The typical high glycemic load, low fat diet gathered 60% of its energy from carbohydrates w/20% from fat & protein each.  The low glycemic index, moderate glycemic load diet obtained 40% of its energy from carbohydrates & fat each w/20% from protein whereas the low carb, low glycemic load diet obtained 10% of its energy from carbohydrates, 60% from fat & 30% from protein.

My first reaction is that it's a sad commentary on our times when a 12 week study of 21 subjects garners national headlines.  But on further introspection, I find myself wondering if I'm ready to make recommendations to a large proportion of the population based upon such a small, short study.  Let's just say that this study makes for excellent hypothesis development.





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Wednesday, June 27, 2012

Cholesterol & Heart Disease: How Much Evidence Do You Need?

For the longest time, the medical profession was not able to determine an(y) association between cholesterol and heart disease, much less cause & effect, at least not until the Framingham study was published.  Since then, multiple studies have been published demonstrating not only a link between high cholesterol and heart disease, but also that actively lowering cholesterol can decrease heart disease risk.  In fact, we now use the Framingham risk calculator in its various guises to help assess heart disease risk and determine LDL (bad) cholesterol goal.

Thus, having swallowed the Kool-Aid figuratively, even so far as to go back & ask for more, it never ceases to amaze me when patients ask for the latest cutting edge, nay, bleeding edge, testing to determine their risk. It's never clear whether they don't believe the Framingham data or whether they're looking for more enticement/rationale/proof before they change their lifestyle and/or start their medication.  They ask for Berkeley Heart Lab, VAP panel, NMR Lipoprofile, PLAC test, etc, by name thanks to fantastic advertising.

I'm one of the first to tell my residents to only order tests that will make a difference in their decision making. If the result won't change the decision, then why waste the money?  And since most, if not all, of the patients asking for these bleeding edge tests (none of which have randomized controlled trials demonstrating effectiveness, just observational studies demonstrating association & correlation) have yet to reach their LDL goal, I typically attempt to dissuade them from wasting their own money.  More importantly, what's the solution to an abnormal test?  More (powerful) statin and therapeutic lifestyle changes.  How is that any different from what we'd already recommended?

In a study published in last week's JAMA, the authors followed 165,544 patients w/o baseline cardiovascular disease for 10+ years.  The addition of apolipoprotein B & A1, lipoprotein(a) & lipoprotein-associated phospholipase A2 to traditional lipid panel led to net reclassification from intermediate risk to high risk of heart disease of less than 1% of those assessed warranting pharmacologic management.  In essence, 4,500 patients w/o known heart disease would need to be tested for additional cardiovascular markers (at great expense) and agree to take a statin for 10 years in order to prevent one extra event.  So while the study may prove these additional bleeding edge tests are statistically significant, I question whether they are truly clinically significant.

I suppose if your crystal ball was in working order and you knew that it would be you who'd be having a vascular event, you'd want the additional testing and you'd be willing to pay for it.  But it doesn't work that way.  We don't know who's going to benefit.  And we all to have to pitch in to an ever increasingly expensive health care system.  Like the law of diminishing returns that we learned about in Economics 101, at some point we have to look at the numbers and declare, "that dog don't hunt".



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Tuesday, June 26, 2012

Bariatric Surgery vs Alcohol Use Disorder

I'm sure you've heard about something being too good to be true.  As much as you want it to be true, don't you always sniff around and investigate a bit?  Poke & prod at it to see if it's really that good?  And too often, when you look hard enough, you'll fine a crack in the armor somewhere.

And so it is w/bariatric surgery in which study after study has demonstrated the ability to lose 100+ pounds post-operatively, something that very few patients can do on their own by dint of lifestyle (ask yourself how many people compete on NBC's Biggest Loser TV show).  Don't get me wrong, it can be done.  Just by increasing intense physical activity to upwards of 4 hours/d and restricting caloric intake to 70-75% of estimated daily resting energy expenditure, these select few were able to lose dramatic amounts of weight equivalent to that achieved by bariatric surgery.  But as I noted already, these are the few, the proud, the Biggest Losers.

More importantly, it's been pointed out in several studies that post-operatively, diabetic bariatric surgery patients are often cured of their diabetes and able to stop medications completely.  But as of this past week, the luster of bariatric surgery has dulled just a bit as Roux-en-Y gastric bypass, in particular, has been linked to an increase in alcohol use disorder (AUD), defined as alcohol abuse & dependence.

As published in JAMA, the authors prospectively followed a cohort of 1,945 obese patients, 79% female, 87% white, avg 47yo w/body mass index 45.8kg/m2 for 2 years post-operatively.  Interestingly, evidence of AUD did not differ over a two year period from 1 year pre-op to 1 year post-op.  However, by the 2nd year post-op, there was a statistically significantly greater prevalence of AUD, especially in younger males who smoked & exhibited AUD & other substance use pre-op.  Most curious of all, those who under Roux-en-Y procedure had a greater risk of AUD compared to those who underwent a laparoscopic adjustable gastric band procedure.

While this was a prospective study, let's not forget that as a cohort study, it was not designed to determine & prove cause & effect.  The conclusions of this study can only link Roux-en-Y procedure in younger men w/previous AUD & polysubstance use pre-op to greater AUD post-op.  For now, we need to be more cognizant of screening for alcohol use in our obese patients, even as we attempt to search for cause & effect.  And as more & more patients opt for bariatric surgery as their solution to obesity, those of us in primary care need to monitor for increased alcohol consumption 2 years post-operatively.


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Monday, June 25, 2012

USPSTF vs Pap Smears

So, did you hear the latest from the US Preventive Services Task Force?  No, not regarding vitamin D.  And no, not regarding screening for prostate cancer w/PSA.  Rather, I'm referring to the update of their 2003 recommendations regarding screening for cervical cancer published, two weeks ago in the Annals of Internal Medicine.

First, we always want to review to whom these recommendations apply.  In this instance, USPSTF is addressing women w/cervix regardless of sexual history who have not had a high-grade precancerous cervical lesion or cervical cancer, been exposed to diethylstilbestrol, or are immunocompromised.

For this very specific group, USPSTF recommends screening for cervical cancer in women aged 21 to 65 years with cytology (Pap smear) every 3 years.  Women who are 30 to 65yo may opt for a combination of Pap smear and human papilloma virus (HPV) testing every 5 years.  On the other hand, HPV testing should not be used in those younger than 30yo.

What came out as a bit of a surprise was that USPSTF recommends against Pap smears for women younger than 21yo and those older than 65yo who've had adequate prior screening and are otherwise at low risk.

What hasn't changed is that USPSTF continues to recommend against Pap smears for women who've had a total hysterectomy (referring to removal of cervix, not ovaries) AND don't have a history of high-grade precancerous cervical lesion or cervical cancer.

Bottom line: know your guidelines, know your groups.

The times, they are a-changin'.
-Bob Dylan



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Sunday, June 24, 2012

Q&A Session at HealthTap.com

When do men and women reach their individual sexual peaks differently?




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Q&A Session at HealthTap.com

Why do people crave sex and others have no interest?




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Q&A Session at HealthTap.com

Does having a complete prostatectomy lower a mans sexual drive?




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Q&A Session at HealthTap.com

Erectile dysfunction--is this a made-up term to sell drugs?




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Q&A Session at HealthTap.com

Is the ed drug muse better than cialis and viagra?




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Q&A Session at HealthTap.com

What is some info on the erectile dysfuntion medication 'muse'?




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Q&A Session at HealthTap.com

Using muse for mens erection. Is it ok for diabetic people?




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Q&A Session at HealthTap.com

How do you use a male enhancement drug called muse?




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Q&A Session at HealthTap.com

What should I know about the erectile prescription called muse?




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Q&A Session at HealthTap.com

What is the drug that causes the effect in ED drug muse?




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Q&A Session at HealthTap.com

What can i expect while taking muse for erectile dysfunction ED?




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