Tag: Evidence Based Medicine

ADS – Anticoagulation

I think the bottom line for this ADS is “Adam, you need to review your primary literature for anticoagulation”. The session certainly brought up a lot of primary literature, but also raised a couple of clinical controversies. The take-home messages I got were:

– Basically anyone who is immobile, has recently had surgery, or has cancer or another medical condition predisposing to clots requires DVT prophylaxis. Harking back to Clinical Orientation, the words of Mike: “You need to talk yourself out of DVT prophylaxis rather than into DVT prophylaxis”.
– Hip surgery > knee surgery for clot risk, therefore treat longer.
– The BRIDGE trial only included A-fib patients with a mean CHADS2 of 2, so only consider bridging therapy for high-risk clotters…in terms of other high-risk clotting scenarios, there is less to no evidence.
– CONTROVERSY: the rivaroxaban EINSTEIN-PE trial, although it showed non-inferiority to warfarin, had a wide confidence interval (CI), whereas AMPLIFY had a tighter CI when showing non-inferiority to warfarin.
– I always thought VTE treatment in cancer patients was always with indefinite duration until malignancy is resolved, but it turns out it is >6 months. PO options for this population are pending trials (MATISSE subgroup)

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Reflections on Evidence-based Medicine

It was really great to see the other residents, both hospital and community alike. Although by the end of a Friday afternoon it was tough to sit in one spot for 7-8 hours, there are many things to unpack and revisit throughout the residency year when it comes to appraising the literature, always having a critical lens, and (what I found to be an important talk) keeping your patient’s wishes in mind. So, how did I do on my goals?

Goal #1: Develop an efficient process for appraising a variety of literature, including RCTs, observational studies, meta-analyses, systematic reviews, and guidelines. I’d like to believe I have achieved this in that I have a good foundation and framework for approaching a variety of literature. For all the “checklists” and “scores”, I don’t think I’ll be using them for every single study I come across, but they are good for keeping in mind what elements make up a quality study.
– For observational studies, I have the STROBE checklist
– For guidelines, I have the AGREE II scoresheet
– For meta-analyses, there is the PRISMA checklist and AMSTAR score. I liked AMSTAR because it is fast, and a quick hit on what “big-picture” things to look out for in a meta-analysis.

Goal #2: Develop a process to approaching clinical dilemmas and treatment choice with patients. Achieved. Dr. Slavik provided us the 10 step workflow to doing this. The main idea I got from this was to start big when explaining medication choice, such as:
Condition (what it is) –> Drug class options –> Individual drugs –> Tangible risks (don’t give an NNT) –> Tangible benefits –> side effects, cost, other factors

Overall, the surprising thing I learned during this week was that meta-analyses are not as necessarily bulletproof as I’d like to believe. I think during undergrad, it was drilled into our heads that RCTs have a lot of areas where investigators can improve on, but I was part of a large group of my colleagues who imagined that as we were told that meta-analyses are at the “top of the evidence food chain”, they have to be of a higher quality.

Another thing that made me reflect and give me more pause was that certain research questions may be better answered by a cohort or case-control study, such as in the cases of rare adverse events, hypothesis-generating studies, or ones where larger studies may be impractical or too expensive.

Goals and Objectives: Evidence-based Medicine Rotation

Goal #1: Develop an efficient process for appraising a variety of literature, including RCTs, observational studies, meta-analyses, systematic reviews, and guidelines.
Objectives to meet this goal:
– Remain engaged during the didactic sessions and ask questions of my colleagues and the facilitator where necessary
– Develop a “hit-list” of 3-5 elements to look for in a paper or guideline to determine whether the evidence is applicable to a patient under my care, and whether I should continue appraising a paper before moving on to the next one
– Develop a “hit-list” of 2-3 elements to look for bias or systematic weaknesses in a paper or guideline to efficiently triage papers for more extensive review

Goal #2: Develop a process to approaching clinical dilemmas and treatment choice with patients.
Objectives to meet this goal:
– Develop an approach to elucidating patient values within the first 2 minutes of a patient interaction
– Endeavour to use zero medical jargon during each patient interaction, and to explain medical jargon not previously clarified
– Present at least 2 alternatives and 2 pros and cons for each treatment option, and develop a process to develop these pros and cons based on patient values

QTc prolongation + Torsades de Pointes risk stratification and management

For this Nugget of Knowledge, I put several tags on it because I think I will be referring to it on multiple rotations…I just picked the ones that I suspect it will come in most handy.

Probably not the first thing that comes to mind when one thinks about drug distribution, but always a thing to keep in mind on a dispensary shift if a patient is on a bunch of QT prolonging drugs – how do you know who is at higher risk than another? Today I attended a CSHP webinar on this very topic; here are some pearls I picked up:

FDA and Health Canada definition of a prolonged QTc
>500 ms OR >60 ms above baseline

Beware of the hypos – K, Mg, and Ca

Risk stratification tool #1 – Tisdale et al – validated in cardiac critical care units
– Assigns varying point values to different risk factors
– Offending DRUGS are given more weight than say, hypokalemia
– Great positive predictive value for high risk individuals
– They did not routinely measure magnesium levels
– However, only predicts risk of prolonged QT, NOT TdP or any hard outcomes such as mortality.

Risk stratification tool #2 – Haugaa et al with the Mayo Clinic – not validated, but had patients across the board: peds, medicine, cardiology, ICU, you name it
– EQUAL weighing of risk factors
– Hard outcome: mortality
– Good predictive value of mortality for scores 4 or above
– ONLY valid for baseline QTc of 500 ms or greater

These tools are great for stratifying patients according to risk and will help me prioritize interventions. As always I would perform NESA on each offending drug (or each option to treat a condition) to see if it is worth the risk. Also, downloaded the CredibleMeds app onto my phone – a great tool to quickly look up rough risk levels for various medications to prolong the QT interval.