Primecuts – This Week In The Journals

August 24, 2015


china explosionBy Neha Sathe, MD 

Peer Reviewed 

As new fires ignite at the enormous Tianjin blast site in northern China, concern mounts regarding exposure to 700 tons of toxic chemicals that had been stored there. The initial explosion, a tragedy that claimed 116 lives and destroyed 17,000 homes, released high levels of such chemicals as sodium cyanide, which continues to affect local air and water quality.

While China moves to control this chemical exposure, Africa celebrates one year without a new case of polio on the continent. The success was achieved through large immunization drives, primarily in Nigeria, which accounted for half the world’s cases as recently as 2012.

To close this week in news, 3 Americans made international headlines for subduing a gunman with an AK-47 machine gun on a high-speed train in France, thus thwarting a potential tragedy.

This week in medical news, research highlights the potential benefit of a subcutaneous weight loss drug for overweight type 2 diabetics, early colectomy in ulcerative colitis, and adenosine guided ablation for patients with atrial fibrillation, while screening for occult malignancy with computed tomography of the abdomen and pelvis shows no benefit for asymptomatic patients with unprovoked venous thromboembolism.

Liraglutide lowers weight and improves glycemic control in obese patients with type 2 diabetes. [1]

Obesity is a challenging epidemic, in part due to the difficulty of achieving and maintaining weight loss. Diabetes mellitus and obesity share many pathologic hormonal changes, and weight loss has been shown to improve glycemic control. Liraglutide, a glucagon-like peptide 1 (GLP-1) analog administered as a subcutaneous injection, carries a potential to treat both obesity and type 2 diabetes.

The SCALE trial was a double-blind, placebo-controlled, parallel-group, multi-site trial that randomized 846 patients with BMI > 27.0 and type 2 diabetes (Hgb A1c 7-10%) to 1 of 3 groups: liraglutide 3.0 mg, liraglutide 1.8 mg, and placebo.

Participant experienced weight loss of 6.0% (6.4kg), 4.7% (5.0kg), and 2.0%(2.2kg) in these groups, respectively, at the end of 56 weeks. A significantly higher fraction of patients in the in the liragutide groups lost >5% and >10% of body weight compared to placebo. Multiple measures of glycemic control were also significantly better in the liraglutide groups. Adverse effects, primarily gastrointestinal, were more common in the liraglutide groups.

Whether these effects change cardiovascular health has yet to be explored; however, liraglutide represents an exciting new treatment option for obesity and diabetes.

CT of the abdomen and pelvis to screen for malignancy provides little clinical utility in patients with unprovoked venous thromboembolism. [2]

Venous thromboembolism (VTE) can be an early sign of malignancy, to the degree that up to 10% of patients first diagnosed with unprovoked venous thromboembolism are then diagnosed with cancer within 1 year. For this reason, physicians frequently assess for underlying malignancy in patients presenting with venous thromboembolism unexplained by another risk factor; however, practices vary widely.

The SOME trial was a multicenter randomized trial that examined patients with first-time unprovoked symptomatic venous thromboembolism (lower extremity and/or pulmonary). 854 patients (of 3186 assessed) were randomized to either a limited cancer screening strategy (including history and physical, basic blood testing, chest radiography, and standard age-appropriate cancer screening) or the same limited strategy plus CT of abdomen and pelvis. There were no significant differences in the rate of missed cancers, the time to cancer diagnosis, or in cancer-related mortality between the two groups. While selection bias limits the study’s generalizability, the results help inform the workup of new VTE. Conservative CT scan use can also help restrict radiation exposure and preserve hospital resources.

Elective colectomy is associated with improved survival compared to medical therapy among patients with advanced ulcerative colitis. [3]

Although treatment for ulcerative colitis typically begins with medical therapy, standard medications are associated with high failure rates and increased infection rates. An alternative treatment is colectomy, which may carry relatively low morbidity and mortality when done electively. A retrospective cohort study included 830 patients with ulcerative colitis pursuing electively colectomy and 7541 matched patients with ulcerative colitis pursuing medical therapy. Mortality rates was 34 per 1000 person-years for elective surgery, versus 54 per 1000 person-years for medical therapy, with elective surgery associated with improved survival (adjusted hazard ratio 0.67 [95% confidence interval, 0.52-0.87]). Although this result was not significant in all sensitivity analyses and the study design is liable to confounding, it provides compelling evidence for further trials to determine the standard of care in ulcerative colitis.

Adenosine testing to guide pulmonary vein isolation ablation for atrial fibrillation may reduce recurrence of symptomatic atrial fibrillation. [4]

One rhythm-control strategy for atrial fibrillation is catheter ablation of pulmonary vein conduction, however recurrence of atrial fibrillation approaches 50%. Adenosine can induce conduction in otherwise dormant areas of the pulmonary veins, and thereby unmask areas that may contribute to recurrent arrhythmias. In the ADVICE study, a multicenter randomized trial, 534 patients with symptomatic atrial fibrillation underwent catheter ablation and then adenosine testing to identify dormant conduction. The 284 patients with dormant conduction were randomized to additional ablation based on adenosine testing or to no further ablation. Additional ablation was successful in 97% of patients, although the procedure time was significantly longer. Freedom from any atrial tachyarrythmias was significantly greater in the group assigned to further adenosine guided ablation (65.3% versus 39.4%, p<0.0001).   While experience with this technique is limited, this strategy enhances available options for rhythm control in atrial fibrillation.

Quick cuts:

In an observational study of 2285 patients with type 2 diabetes and stable ischemic heart disease, investigators found that 99.6% had detectable Troponin T (>3ng) levels, and 39.3% had abnormal (>14 ng/L) troponin T levels. Those with abnormal troponin levels were more likely to have a composite end point of death from cardiovascular causes, myocardial infarction, or stroke, versus those with normal levels (27% versus 12.9%, P <0.001), although randomization to early revascularization based on troponin T did not demonstrate a benefit.[5]

Alta Charo, JD makes a strong argument for the use of fetal tissue for research and therapy in the New England Journal of Medicine. [6] The topic comes into play after renewed political threats to defund Planned Parenthood, sparked by questions regarding the organization’s retrieval of fetal tissue for research.

A review of electrolyte and acid-base disturbances in diabetes mellitus outlines disturbances in sodium and potassium levels, the development of both gap and non-gap acidosis, and relevant elements of renal physiology. [7]

A review of septic shock, which affects 230,000 patients in the United States each year, highlights advances in treatment, including the utility of focused ultrasonography, criteria for invasive hemodynamic monitoring, and ongoing debate over crystalloids. [8]

Dr. Neha Sathe is a 1st year resident at NYU Langone Medical Center 

Peer reviewed by Kerrilynn Carney, MD, Chief Resident, NYU Langone Medical Center 

Image courtesy of BBC.Com. http://www.bbc.com/news/world-asia-china-34029202

References

 

  1. Davies MJ, Bergenstal R, Bode B, et al. Efficacy of Liraglutide for Weight Loss Among Patients with Type 2 Diabetes. JAMA. 2015;314(7):687-699. https://jama.jamanetwork.com/article.aspx?articleid=2428956
  2. Carrier M, Lazo-Langner A, Shivakumar S, et al. Screening for Occult Cancer in Unprovoked Venous Thromboembolism. NEJM. 2015;373(8):697-704. http://www.nejm.org/doi/full/10.1056/NEJMoa1506623
  3. Bewtra M, Newcomb CW, Wu Q, et al. Mortality associated with medical therapy versus elective colectomy in ulcerative colitis. Ann Intern Med. 2015;163:262-270. http://annals.org/article.aspx?articleid=2395724
  4. Macle L, Khairy P, Weerasooriya R, et al. Adenosine-guided pulmonary vein isolation for the treatment of paroxysmal atrial fibrillation: an international, multicentre, randomised superiority trial. Lancet. 2015 ; 386 :672-679. http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(15)60026-5/abstract
  5. Everett BM, Brooks MM, Vlachos HEA, et al. Troponin and Cardiac Events in Stable Ischemic Heart Disease and Diabetes. N Engl J Med. 2015;272:610-620. http://www.nejm.org/doi/full/10.1056/NEJMoa1415921?query=featured_home
  6. Charo RA. Fetal tissue fallout. N Engl J Med. Epub ahead of print. Posted Aug 12 2015. Accessed Aug 17 2015. http://www.nejm.org/doi/ref/10.1056/NEJMp1510279#t=article
  7. Palmer BF and Clegg DJ. Electrolyte and Acid-Base Disturbances in Patients with Diabetes Mellitus. N Engl J Med. 2015;373:548-59. http://www.nejm.org/doi/full/10.1056/NEJMra1503102
  8. Seymour CW, Rosengar MR. Septic Shock: Advances in Diagnosis and Treatment. JAMA. Aug 18 2015;314(7):708-717. http://jama.jamanetwork.com/article.aspx?articleid=2428960