March 17, 2017

FIbs and strokes

The story

They say blood runs thicker than water, but that's a problem for patients with a fib. New research shows who is and isn't on therapeutic anticoagulation.

The background

Atrial fibrillation (AF) accounts for 10 - 15% of the 700,000 annual strokes in the United States. Therapeutic anticoagulation (AC) reduces stroke risk in AF patients and makes strokes less severe, but remains substantially underused. Little is known about therapeutic AC in AF patients prior to ischemic stroke, especially in the era of novel oral anticoagulants (NOACs).

The study

Were AF patients who suffered stroke or TIA on therapeutic anticoagulation at the time of their stroke? Researchers retrospectively evaluated 100,000 cases of AF patients with a CHA2DS2VASc score ≥ 2 who suffered ischemic stroke and found that a whopping 84% of patients were not on therapeutic AC. Thirty percent were on no form of anticoagulation at all, 40% were on antiplatelet therapy, and 14% were on subtherapeutic warfarin. Of patients who were not on any form of AC, 30% did not have a documented reason explaining why the meds weren't started.

The hits and misses

Of the patients on therapeutic AC, analyses estimated that warfarin cut the risk of stroke by about half and NOACs cut it by about 35%, though the difference between the two classes of medications was not significant. Two-thirds of warfarin patients, however, had a subtherapeutic INR at the time of their stroke, highlighting the difficulties associated with INR monitoring. Patients from both medication groups had less severe strokes than their non-anticoagulated counterparts.

The takeaway

The research suggests that appropriate AC could have prevented a tremendous number of ischemic strokes. Since so many of the patients on warfarin were subtherapeutic at the time of stroke, consider placing your patients on NOACs when appropriate.

Say it on rounds

When it's late on St. Patty's Day, and you reach for a last drink

Things that seem good at the time can bite you later. Take angiotensin-converting-enzyme inhibitors (ACE-i): an increase in creatinine of up to 30% is classically considered benign after the meds are started. But a population-based cohort study of over 100,000 patients in the UK found that creatinine increases associated with ACE-i initiation were linked in stepwise fashion to worse long-term cardiorenal outcomes (ESRD, MI, heart failure, and death). The findings held for each 10% incremental increase in creatinine, even for values below 30%.

When your caffeine habit needs more excuses

A prospective cohort study of over 6,000 patients found that individuals who reported drinking tea regularly (≥1 cup per day, black or green) had slower progression of coronary artery calcium on imaging compared to non-drinkers after a median follow-up of 5 years. After 11 years of follow-up, the tea drinkers had a 30% lower incidence of cardiovascular events. Self-reported coffee intake appeared neutral with respect to coronary artery calcium progression.
Am J Med

When you get jazzed about your patients' lab holidays

Everyone needs an excuse to celebrate, and we can all celebrate when lower costs lead to equal outcomes. A retrospective analysis of hospitalists and general internists over 4 years revealed more variation in spending between physicians of the same hospital than across hospitals, with intra-practitioner spending differences of up to 40%. There were no differences in 30-day mortality or readmissions among high vs. low spenders, suggesting that individual practice patterns may merit more attention in cost-saving initiatives.
JAMA Int Med

Brush up

Under the weather

Some influenza infections are asymptomatic, but most will make you and your patients feel pretty miserable. Look for high fevers, malaise, and myalgias as clues in the clinical history. Viral shedding peaks over the first 1-2 days of clinical illness, and tends to correlate with the severity of clinical symptoms. Since the sensitivity of clinical diagnosis is highly variable, look to test for the virus early in the course of illness with nasopharyngeal swabs and aspirates. The WHO and CDC recommend surgical masks for any healthcare workers caring for infected patients.

What's the evidence

For influenza vaccine efficacy? Your patients love quibbling about the flu shot, so it’s good to have numbers on your side. Using a model that compares the incidence of flu in those who are vaccinated against those who aren’t, the CDC estimates that that the 2015 - 2016 flu season vaccine prevented 5 million cases of flu, 2.5 million medical visits, 71,000 hospitalizations, and 3,000 deaths. The estimates are available yearly.

Work work work work work

No one's dancing after 24-hour call. But the ACGME, citing a lack of benefit from capped duty hours in studies of surgical interns, removed the 16-hour shift restriction for interns beginning this July. This team of writers, happy that our days of 27-hour shifts are mostly in the rearview, can't recall a headache-free recovery period after 24+ hours on the job.

Spread the word

Congrats to all of the fourth year medical students participating in the Match! We're proud of you and all you've accomplished up to this point. Be sure to share The Scope with your new colleagues.  


We're on break next week as we continue our travels in South Africa. We'll be back with more on March 31st.

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