Primecuts – This Week In The Journals

January 28, 2013

By Jillian Rosengard, MD

Faculty Peer Reviewed

This week we bundled up to bear the brutal cold, watched President Obama’s second term inaugural address, and inched closer to our return to Bellevue. Meanwhile, an article from this week’s New England Journal of Medicine gained media attention. Jha et al’s retrospective cohort study of more than 200,000 Americans examined cigarette smoking’s effect on survival and the benefits of smoking cessation. After accounting for potential confounders (namely education level, alcohol use, and obesity), life expectancy for current smokers was reduced by 11 and 12 years compared to men and women, respectively, who never smoked. While there have been previous large cohort studies documenting the adverse health consequences of cigarette smoking, this study was unique because the women in the cohort are among the first generation who began smoking early in life and continued to smoke heavily for several decades. Furthermore, this study quantified the mortality benefit of smoking cessation for different ages. Subjects who stopped smoking between 25 and 34 years of age had nearly identical survival curves to those who never smoked. Participants who quit smoking between ages 35-44 years, 45-54 years, and 55-64 years, however, gained approximately nine, six, and four years of life, respectively. This study will certainly be useful in discussing the benefits of smoking cessation with patients. Furthermore, these statistics are also pertinent to former smokers, who now outnumber current smokers in the US. It would have been useful to examine the impact of smoking cessation on individuals over 65 years of age.

In another large retrospective study, Dharmarajan et al’s publication in JAMA analyzed Medicare patients who were readmitted within 30 days of hospitalizations for heart failure, acute MI, and pneumonia, representing 24.8%, 19.9%, and 18.3% of all patients hospitalized for those diagnoses, respectively. Not coincidentally, these are the three diagnoses for which Medicare monitors readmission rates and provides incentives to reduce readmissions. More than 60% of readmissions for all three of these diagnoses occurred within 15 days of discharge, though readmission rates remained high throughout the thirty-day period, suggesting that close follow-up is warranted for these patients. Interestingly, the readmission diagnosis was different from the initial diagnosis for the majority of patients in all three cohorts. This finding is significant because it reveals the importance of broad, multi-disciplinary follow-up strategies. I believe that it also highlights the impact of hospitalization on elderly patients and their subsequent increased vulnerability to a myriad of problems even days to weeks after discharge.

In the world of vascular medicine, researchers from the University of Pennsylvania published a study in Circulation that asked whether a mechanism for aspirin resistance exists. This prospective study consisted of 400 individuals who ingested either 325mg of regular aspirin or 325mg of enteric-coated aspirin. “Response” was measured by inhibition of maximal arachidonic acid-induced platelet aggregation (as compared to predose aggregation), and those who had <60% inhibition were considered “non-responders.” Only individuals in the EC aspirin group met criteria to be classified as non-responders. Among the non-responders, the majority responded when the single dose was repeated at a later date, and all but one had appropriate molecular response to aspirin 81mg daily for seven days. These results suggest that true aspirin resistance does not exist, but that we can observe pseudoresistance with enteric-coated aspirin secondary to variable and delayed absorption. Of note, the study population included young healthy adults who were not taking other medications. I believe that a larger study of individuals who more closely reflect the population normally taking daily aspirin is needed in order to provide convincing evidence that true aspirin resistance does not exist.

Lastly, on to Neurology – researchers from the Mayo Clinic conducted a retrospective cohort study of fifty-four patients to examine the role of continuous EEG in patients undergoing therapeutic hypothermia after cardiac arrest. Using a novel EEG grading system, patients’ EEGs received grades of 1, 2, or 3 (mild, moderate, or severe) during therapeutic hypothermia, rewarming, and normothermia. EEG grade corresponded with clinical outcome (using the Cerebral Performance Category Scale) and few patients exhibited a change in EEG grade from stage to stage. Five patients experienced seizures and they all had bad clinical outcomes despite recognition and treatment of their seizures; however, all five of these patients had “severe” grade EEGs at baseline and received different anti-epileptic regimens. We cannot conclude whether identifying and treating seizures in this population impacts outcome based on only five patients, especially because each received distinct therapies. Continuous EEG for cardiac arrest patients undergoing hypothermia demands significant hospital resources, and not all facilities have the capacity to do this. Finally, an ideal larger study would capture more patients who experienced changes in their EEG grades, and those who experienced seizures would receive standardized treatment.

Other articles published this week:

Neurology: Low Prevalence of Neurocognitive Impairment in Early Diagnosed and Managed HIV-infected Persons – http://www.neurology.org/content/80/4/371.abstract -The prevalence of neurocognitive impairment in HIV+ patients who were diagnosed and managed early was comparable to matched HIV- individuals.

British Medical Journal: Women’s Views on Overdiagnosis in Breast Cancer Screening: A Qualitative Study – http://www.bmj.com/content/346/bmj.f158 – Women of various backgrounds were able to grasp the issue of overdiagnosis, highlighting the importance of thorough communication.

Nature Medicine: Neglected Diseases See Few New Drugs Despite Upped Investment – http://www.nature.com/nm/journal/v19/n1/full/nm0113-2.html – One proposed explanation is that basic research is receiving significantly more funding than product development.

The Lancet: Antibody-mediated Vascular Rejection of Kidney Allografts: A Population-based Study – http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2812%2961265-3/fulltext – They identified four patters of kidney allograft rejection, including one phenotype that is not included in current classification schemes – antibody-mediated vascular rejection, for which new therapeutic approaches should be considered.

Dr. Jillian Rosengard is a 1st year resident at NYU Langone Medical Center

Peer reviewed by Lakshmi Tummala, MD,  Associate Editor, Clinical Correlations.

Image courtesy of Wikimedia Commons

References:

1. Jha P, et al. 21st-Century Hazards of Smoking and Benefits of Cessation in the United States. NEJM. 2013;368(4):341-350.  http://www.nejm.org/doi/full/10.1056/NEJMsa1211128

2. Dharmarajan K, et al. Diagnoses and Timing of 30-Day Readmissions After Hospitalization for Heart Failure, Acute Myocardial Infarction, or Pneumonia. JAMA. 2013;309(4):355-363. http://jama.jamanetwork.com/article.aspx?articleid=1558276#qundefined

3. Grosser T, et al. Drug Resistance and Pseudoresistance: An Unintended Consequence of Enteric Coating Aspirin. Circulation. 2013;127(3):377-385. http://circ.ahajournals.org/content/early/2012/12/04/CIRCULATIONAHA.112.117283.abstract

4. Crepeau AZ, et al. Continuous EEG in Therapeutic Hypothermia After Cardiac Arrest: Prognostic and Clinical Value. Neurology. 2013;80(4):339-344. http://www.neurology.org/content/80/4/339.abstract

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