Tidings from the Citadel: Warfarin in Dialysis

Warfarin Use and the Risk for Stroke and Bleeding in Patients With Atrial Fibrillation Undergoing Dialysis – Mitesh Shah et al. Circulation. 2014;129:1196-1203.

A retrospective cohort study

Population based cohort of patients > 65 years who were admitted in Canada – Quebec and Ontario with a primary or secondary diagnosis of atrial fibrillation. Used ICD-9/10 codes to determine diagnosis and complications such as bleeding and stroke complications. Drug prescriptions were identified by database in Canada where patients > 65 have prescription benefit. Warfarin use was identified by a filled prescription within 30-days of AF diagnosis

Patients
626 dialysis patients and 204,210 nondialysis patients. Did not separate by stages of CKD, but rather HD or non-HD. Dialysis patients were younger, male, CHF, HTN, DM, CAD, and bleeding history.

Dialysis vs Non-Dialysis: CHADS2 >/= 2: 72% versus 55% (indication for anti-coagulation); HAS-BLED >/=3: 85% versus 25%. Similar rates of warfarin prescription (46% vs 51%)

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Stroke
In non-dialysis patients, warfarin users had a lower incidence of stroke (2.19 vs 2.51/100 person-years)

In dialysis patients, stroke incidence was similar for warfarin and non-warfarin users: 3.37 versus 2.91/100 person-years.

After adjusting for confounders – warfarin use had a HR of 1.14 in diaylsis patients. While in non-dialysis patients had a HR 0.87 with warfarin use.

Bleeding
After adjusting for confounders, warfarin use, was associated with a 44% higher risk for bleeding event in dialysis patients and 19% higher risk in nondialysis patients.

 

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Flea Bytes: Calf DVTs

Randomized double blind placebo-control trial that faced slow recruitment thus faces the problem of being underpowered to detect a difference.

Outpatients without cancer or prior VTE with symptomatic calf DVT. Assigned 1:1 to receive nadroparin or placebo daily for 6 weeks. All were given compression stockings and followed for 90 days.

Primary outcome was extension to proximal vein, contralateral proximal DVT, or systemic embolism by day 42.

Safety outcome – non-major bleeding by day 42.
122 patients in nadroparin and 130 placebo.

Primary outcome 3% in the nadroparin and 5% in placebo. 5 patients had bleeding in nadroparin arm with 1 major bleeding event.

Need more information before change in practice.

Anticoagulant therapy for symptomatic calf deep vein thrombosis (CACTUS): a randomised, double-blind, placebo-controlled trial – M Righini et al; Lancet Haematology, The, 2016-12-01, Volume 3, Issue 12, Pages e556-e562.

Flea Bytes: Enhancing Teaching Effectiveness

Enhancing Teaching Effectiveness and Vitality in the Ambulatory SettingKelley M Skeff, MD, PhD

The Stanford Method

Seven-component Framework to Enhance Teaching Effectiveness

1. Establishing a Positive Learning Climate
-Reflects the degree of stimulation, enthusiasm, comfort, and excitement
-Demonstrate enthusiasm for the content being taught and for teaching itself
-Assess if the setting is conductive to teaching

2. Control of the Teaching Session
-Task-management approaches a teacher uses to focus and pace a session
-Time is limited, need to organize the session to manage time well
-Focus on several areas including ongoing disease processes, cost of care, and health maintenance (outpatient). Also need to evaluate and supervise house officers. can’t focus on all aspects and need to respect the time limitations for learners and patients.

3. Communication of Goals
– Expectation setting: educational experiences they should have, attitudes, knowledge and skills that should be acquired.
– Define specific observable behaviors you’d like to see

4. Enhance Understanding and Retention
– Attitudes: learners should have opportunities to consider and discuss their present attitudes, conceptualize their role, and discuss and set their own goals in a supportive environment.
– Knowledge: present material in clear and organized manner, emphasize key points to be remembered, and actively involve the learner in the process.

5. Evaluation
– Formative evaluation – conducted throughout education experience – helps plan future education experiences to help the learn master desired goals
– Summative evaluation – assessing learners final competence.

6. Feedback
– provide information to improve performance.
– inform, reinforce, or praise when performance is acceptable to excellent
– inform and constructively criticize when performance is needing improvement
– referencing stated expectations can provide the standard for feedback
– ensure time for feedback

7. Self-directed Learning

Flea Bytes: Hepatic Cysts

More common in women, 1.5:1 female to male ratio. 5% of people have cysts on autopsy and 5% of these are neoplastic. The majority of liver cysts (90%) are asymptomatic. Found incidentally on US or CT. Neoplastic cysts are mostly solitary. US imaging is most helpful and CT scan are used in specific cases. US helps determine content of the cysts. Certain cysts are responsive to estrogen.

Location in the liver does not help differentiate neoplastic from non-neoplastic.

Non-neoplastic cysts: wall is smooth, no septa, and no debris. Presence of these suggests the possibility of biliary cystadenoma or cystadenocarcinoma.

Liver tests are normal. In cases of congenital polycystic liver disease alkaline phosphatase maybe elevated.

Surgical removal and histologic sectioning is the only way to determine if neoplastic or not.

First must rule out Echinococcus – endemic worldwide and associated with rural areas with sheep. Test with ELIZA which is 90% sensitive. If surgery is not an option can consider aspiration. Mucin in cystic fluid is concerning for malignancy, but absence does not rule out malignancy. Also can check CEA and CA 19-9 in the aspirate, but inadequate NPV.

Monitor cysts that are 1-2cm, but if they grow to 2-5 consider, and definitely > 5 cm must consider surgery.

If all of the cyst tissue is removed, recurrence is unlikely, however if any part of the cyst wall is left behind recurrence can be up to 50%.
References:

Advances in Hepatology: Current Developments in the Treatment of Hepatitis and Hepatobiliary Disease: Managment of Heaptic Cysts – Jorge L Herrera
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2886389/

Tidings from the Citadel: Accuracy of Lung Ultrasonography in the Diagnosis of Pneumonia

16 studies were included – significant heterogeneity, but of 2359 patients. Heterogeneity was assessed graphically and with a Q test. The Q test should only be used once in a data set to exclude outliers. The reference standard, we considered it to be of high quality if based on CT alone or when it consisted of a final diagnosis made by experts using an integrated synthesis of radiology and laboratory or microbiological data (or both).

The highest risk of bias stemmed from the flow of patients within each study because of an uneven application of the reference test (differential verification bias).

The dispersion of studies in the ROC plane suggests marked heterogeneity.
The 95% CI of the overall effect indicates a sensitivity of approximately 80% to 90% and a specificity of 70% to 90%.

References:
Accuracy of Lung Ultrasonography in the Diagnosis of Pneumonia in Adults: Systematic Review and Meta-Analysis – Ana M. Llamas-Álvarez, MD; Eva M. Tenza-Lozano, MD; and Jaime Latour-Pérez, MD, PhD; . Chest 2017; 151(2):374-382

Flea Bytes: Antibiotics or Surgery for Spinal Epidural Abscess

Baseline rates of treatment failure have varied in studies and rates have ranged from 8.5 to 17% in the best case scenarios to 43-75% in other studies. So even at baseline, we know that a significant number of patients will fail antibiotics and require surgery. Risk factors include diabetes mellitus, leukocytosis greater than 12.5, positive blood cultures, and C-reactive protein greater than 115. One risk factor increases failure rates for to 35.4%, two risk factors increases failure to 40.2%, and three or more risk factors increases failure rates to 76.9%.

So basically, most patients should ideally managed with surgery and barring that we should advocate for surgery in patients who have risk factors. 

Flea Bytes: Duration of Antibiotics for Intra-abdominal Abscess

STOP-IT trial: In patients with intraabdominal infections WITH source control, outcomes were similar between fixed duration (4 days) vs. duration guided by clinical improvement – 2 days after the resolution of fever, leukocytosis, and ileus (mean 8 days). Both intention to treat and per-protocol analysis found no difference. However, the study was terminated early due to funding, and only enrolled half the intended patients.

Stopit

 

Reference:
N Engl J Med 2015;372:1996-2005