Primecuts – This Week In The Journals

By Daniel Diaz, MD

Faculty Peer Reviewed

Now that the New Year has rolled in and winter has finally started to declare itself, it’s time for us to stop making resolutions and start acting upon them. Whether it’s losing weight, quitting smoking, or getting into shape, January is a very popular time to turn over a new leaf judging by the number of new gym memberships and fad diets that abound this time of year.

For those of us who overindulged during the holiday season, a study in JAMA this week examined the relationship between overeating, dietary protein intake, and body composition [1]. In this single-blinded, randomized controlled trial, 25 healthy, weight-stable individuals were placed on low (5%), normal (15%), or high (25%) protein diets. Each diet also had a caloric excess of 40% (approximately 950 extra calories per day). After 8 weeks, those on the low-protein diet experienced significantly less weight gain (3.16kg) compared with the normal- (6.05kg) and high-protein (6.51kg) diets (p=0.002). However, all three groups gained similar amounts of body fat (3.45-3.66kg, p=0.91). More than 90% of the excess energy in the low-protein group was stored as fat versus only 50% in the high-protein group, with most of the remainder going to lean body mass.

These results are useful for counseling patients who are trying to lose weight, as it supports prior research showing that calorie intake is more important than nutrition where weight loss is concerned. It should be noted, however, that these results apply only to weight gain, not weight loss, and that most of the study participants were male, although no significant difference between the sexes was discovered.

Another study in JAMA this week presented new data from the Swedish Obese Subjects (SOS) trial which suggests that bariatric surgery may provide long-term cardiovascular benefits in obese individuals [2]. The ongoing study was structured as a non-randomized controlled prospective study; patients who received bariatric surgery from 1987 to 2001 were compared with controls with a median follow-up of 14.7 years. The authors found that patients who underwent bariatric surgery had lower rates of stroke or MI (hazard ratio 0.67, p <0.01) and fatal cardiovascular events (hazard ratio 0.47, p=.002). In an interesting twist, the rate of cardiovascular events did not correlate with subjects’ BMI, but did scale with baseline plasma insulin level in the control group patients, suggesting that baseline insulin may be a better predictor of who may benefit from bariatric surgery than BMI. However, these conclusions were reached on post-hoc analysis. Additionally, subjects in this trial were not randomized, leading to potential confounding.

In other news, a randomized non-blinded trial published this week in the Annals of Internal Medicine studied the effects of various treatments on acute and subacute neck pain [3]. Two hundred and seventy two patients aged 18-65 who were complaining of neck pain for 2-12 weeks were randomized to either 12 weeks of spinal manipulation therapy (SMT) by an experienced chiropractor, home exercises with advice (HEA), or medication provided by a physician. The study found a statistically significant increase in pain reduction in the SMT group v. the medication group (0.94 point reduction at 12 weeks, p=0.001), with no statistically significant differences found between spinal manipulation therapy and home exercises with advice. Additionally, fewer adverse events were reported in the SMT and HEA groups (40% and 46% respectively) than in the medication group (60%). Reported events were primarily musculoskeletal in the SMT and HEA groups, while patients receiving medication complained mainly of GI symptoms and drowsiness.

Of note, this study was designed to evaluate only healthy patients with mechanical neck pain; it excluded patients with cervical fracture or instability or destructive or inflammatory changes of the cervical spine. The study also excluded patients with significant cardiac disease, progressive neurological deficits, blood clotting disorders, infectious disease, or other severe disabling health problems. Nevertheless, these therapies show promise, especially in patients who have relatively uncomplicated symptoms.

Another study published in the New England Journal of Medicine this week examined the efficacy of a subunit vaccine for HSV-2 [4]. This randomized, double-blinded trial included over 8,000 women aged 18-30 who were seronegative for both HSV1 and HSV-2. They followed the participants for 20 months with a primary endpoint of genital herpes disease due to either HSV-1 or HSV-2. Unfortunately, the trial failed to show a significant reduction in either genital herpes or HSV seroconversion (20% and 22% respectively with 95% CI -29-50% and 2-38%). These results were surprising since two earlier studies in discordant couples showed efficacy rates above 70 percent. On subgroup analysis, there was a statistically significant decrease in HSV-1 genital disease (58% efficacy) and HSV-1 infection (35% efficacy). These results were not mirrored in the HSV-2 analysis. The authors attributed this to various reasons, including fact that the vaccine’s target shared 89% amino-acid homology with its HSV-1 counterpart. While firm conclusions shouldn’t necessarily be drawn from a subgroup analysis, protection against HSV1 would also be useful, as it causes over half of genital herpes cases.

Finally, a cost-effectiveness analysis published in the Annals of Internal Medicine argued for routine screening for HCV in individuals born from 1945-1965 (the cohort most commonly infected with Hepatitis C) using a simulated model based on established data. The study estimated that screening this cohort would cost between $15,700-35,700 per quality-adjusted-life-year saved [5].

As we embark upon a new year and begin to implement all those New Year’s resolutions for ourselves and our patients, the journals this week offered some helpful guidance for us clinicians. With new research showing the benefits of weight loss and protein intake on health, as well as the potential advantages of HSV-1 vaccination, our patients now have a better chance of improving and maintaining optimum health.

Dr. Daniel Diaz is a 1st year resident at NYU Langone Medical Center

Peer reviewed by Ishmael Bradley, MD,  section editor, Clinical Correlations

Image courtesy of Wikimedia Commons

References:

1. Bray GA, Smith SR, de Jonge L, Xie H, Rood J, Martin CK, Most M, Brock C, Mancuso S, Redman LM. Effect of Dietary Protein Content on Weight Gain, Energy Expenditure, and Body Composition During Overeating: A Randomized Controlled Trial. JAMA. 2012 Jan 4;307(1):47-55. http://jama.ama-assn.org/content/307/1/47.full

2. Sjöström L, Peltonen M, Jacobson P, Sjöström CD, Karason K, Wedel H, Ahlin S, Anveden Å, Bengtsson C, Bergmark G, Bouchard C, Carlsson B, Dahlgren S, Karlsson J, Lindroos AK, Lönroth H, Narbro K, Näslund I, Olbers T, Svensson PA, Carlsson LM. Bariatric Surgery and Long-Term Cardiovascular Events. JAMA. 2012 Jan 4;307(1):56-65. PMID: 22215166. http://jama.ama-assn.org/content/307/1/56.full.pdf+html

3. Bronfort G, Evans R, Anderson AV, Svendsen KH, Bracha Y, Grimm RH. Spinal Manipulation, Medication, or Home Exercise with Advice for Acute and Subacute Neck Pain: A Randomized Trial. Ann Intern Med. 2012 Jan 3;156(1 Pt 1):1-10. http://www.annals.org/content/156/1_Part_1/1.long

4. Belshe RB, Leone PA, Bernstein DI, Wald A, Levin MJ, Stapleton JT, Gorfinkel I, Morrow RL, Ewell MG, Stokes-Riner A, Dubin G, Heineman TC, Schulte JM, Deal CD; the Herpevac Trial for Women. Efficacy Results of a Trial of a Herpes Simplex Vaccine. N Engl J Med. 2012 Jan 5;366(1):34-43. http://www.nejm.org/doi/full/10.1056/NEJMoa1103151

5. Rein DB, Smith BD, Wittenborn JS, Lesesne SB, Wagner LD, Roblin DW, Patel N, Ward JW, Weinbaum CM. The Cost-Effectiveness of Birth-Cohort Screening for Hepatitis C Antibody in U.S. Primary Care Settings. Ann Intern Med. 2011 Nov 4. [Epub ahead of print]. http://www.annals.org/content/early/2011/11/03/0003-4819-156-4-201202210-00378.full

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