397 - Screening for HTN, OA Modifying Treatment, Central Hypothyroidism
Take 3 – Practical Practice Pointers©
From the USPSTF
1) Screening for Hypertension in Adults
Hypertension affects approximately 45% of the adult US population and is the most commonly diagnosed condition at outpatient office visits. It is a major contributing risk factor for heart failure, myocardial infarction, stroke, and chronic kidney disease.
The USPSTF recently updated and re-affirmed their 2015 recommendation regarding screening for hypertension in adults. Specifically, the recommendation states:
- Recommend screening for hypertension in adults 18 years or older with office blood pressure measurement (OBPM). (A recommendation)
- Recommend obtaining blood pressure measurements outside of the clinical setting for diagnostic confirmation before starting treatment. (A recommendation)
The office blood pressure measurement (OBPM) is most commonly performed using a manual or automated sphygmomanometer. In the studies reviewed by the USPSTF, OBPM was measured at the brachial artery (upper arm) with the patient most commonly in a seated position after 5 minutes of rest and medical personnel present during measurement. BP readings outside the clinical setting can be accomplished using either ambulatory blood pressure monitoring (ABPM) or home blood pressure monitoring (HBPM) with validated and accurate devices. White coat hypertension can be detected by obtaining out-of-office blood pressure measurements (either through HBPM or ABPM) after an elevated BP measurement is detected in the office.
Confirmation with ABPM would result in the greatest number of cases of sustained HTN being identified without any cases of white coat HTN being treated (by definition, ABPM is considered the gold standard). For this recommendation, the USPSTF used the OBPM threshold of 140/90 to define HTN, and compared it with a reference 24-hour ABPM of 130/80 and daytime ABPM of 135/85. Available data indicate the HBPM threshold of 135/85 appeared most comparable to these OBPM and ABPM thresholds. Limited evidence is available on the accuracy of automated office-based BP measurement (taking repeated measurements while the patient is alone in a quiet room).
Available evidence on optimal screening intervals for hypertension remains limited. The USPSTF suggests annual screening for hypertension in adults 40 years or older and for adults at increased risk for hypertension (such as Black persons, persons with high-normal blood pressure, or persons who are overweight or obese). Screening less frequently (ie, every 3 to 5 years) is appropriate for adults aged 18 to 39 years not at increased risk for hypertension and with a prior normal blood pressure reading.
Not news here, but what strikes me the most as I prepared this Pointer (and reflected on last week’s Pointer regarding CKD and HTN) is the lack of precision both around blood pressure measurements in general and when comparing OBPM, ABPM, and HBPM. This is particularly concerning since all estimates of benefit/risk in guidelines are based on measurements done in controlled settings, which is very different than the often very imprecise measurements done in both the ambulatory and hospital clinical settings.
In my own practice, I continue to look to frequent home BP measurements to guide diagnosis and treatment decisions, and allow the wisdom of Sir William Osler to help guide me: “Good clinical medicine will always combine the science of probability with the art of uncertainty.” Wise words when we become lured into thinking of medicine as an exact science ….
- USPSTF: Screening for Hypertension in Adults. JAMA. April 27, 2021; 325(16): 1650-1656. Link
- Guirguis-Blake J, et al. Screening for Hypertension in Adults: Updated Evidence Report and Systematic Review for the USPSTF. JAMA. April 27, 2021;325(16):1657-1669. Link
From the Literature
2) Disease Modifying Agents for Osteoarthritis
Osteoarthritis (OA) is a challenging disorder to manage in primary care given its progressive nature and largely symptom-based management. The lure of a potential “disease-modifying” treatment is enticing but has been elusive.
This systematic review synthesizes the research behind agents that have been studied for their ability to curtail the joint destruction seen with OA. The authors looked for evidence on: chondroitin, glucosamine, diacerein, matrix metalloproteinase (MMP) inhibitors, collagen hydrolysate, vitamin E, vitamin D, inducible nitric oxide synthase (iNOS) inhibitors, doxycycline, avocado-soybean unsaponifiables (ASUs), hyaluronic acid, bisphosphonates, strontium ranelate, calcitonin, and licofelone.
They included studies that focused on long-term (>= 12 months) outcomes in weight bearing joints (the OA seen in non-weight bearing joints like hands is thought to result from different pathophysiology). They included only studies that had some measure of structural change, i.e., change in joint-space narrowing, in addition to symptom outcomes and adverse events. This was a “network meta-analysis,” which can take the outcomes for a group of placebo-controlled studies and small head-to-head comparison studies and analyze them together to estimate the relative benefits of each intervention compared to all the others. Overall, this was a well-done review.
The authors analyzed 28 studies (judged to be of “moderate quality”) of almost 12,000 patients. Glucosamine and chondroitin were found to have a statistically significant but clinically marginal net benefit on structural outcomes and clinical symptoms. Strontium was associated with small structural benefits only, and vitamin D was associated with small symptomatic benefits only. None of the above was associated with significant adverse events. Doxycycline showed some small clinical and structural benefit, but this was limited by gastrointestinal adverse effects. None of the other medications showed any significant benefit.
I hadn’t heard of most of these potential treatments, which is apparently just as well. Unfortunately, it seems we have not yet found a medication that can change the course of OA of weight-bearing joints, so we are still in the hunt for an effective disease-modifying therapy. For now, our job in primary care can be to counsel safe exercise, activity modification, weight loss (if applicable), and pain control.
- Yang W et al. The Efficacy and Safety of Disease-Modifying Osteoarthritis Drugs for Knee and Hip Osteoarthritis-a Systematic Review and Network Meta-Analysis. J Gen Intern Med. 2021 Apr 12. Link
Clinical Lesson From a Colleague
3) Monitoring and Treatment of Central Hypothyroidism
Question: “I have identified a common clinical error that affects those in both outpatient primary care and inpatient practices: focusing on the TSH in patients with a history of central hypothyroidism, often due to previous pituitary surgery. Would you update our colleagues on this?”
Answer: The usual series of events is similar to this:
- The chart Problem List says "hypothyroidism" or "acquired hypothyroidism," even if the chart also lists "hx of pituitary surgery" or "panhypopituitarism." Sometimes the surgery was MANY years ago and this part of the history was forgotten. Often patients saw an Endocrinologist in the past but stopped seeing them because their doses of levothyroxine and hydrocortisone have been stable for years.
- The Primary Clinician takes over and every time they check a TSH, it is low, and the dose of LT4 is sequentially reduced on each visit during which a TSH is checked.
- Sometimes we just make the patients really symptomatically hypothyroid for 6 months before we figure it out...and apologize.
- But other times, they end up in the ICU with myxedema crisis, hypoglycemia, hypotension, bradycardia to the 30s, and severe encephalopathy, generally precipitated by an acute intercurrent illness such as COVID.
So please remember:
- If the cause of hypothyroidism is CENTRAL, then this should be very clearly documented on the problem list and conflicting diagnoses should be deleted.
- There should also be a reminder in the Comments section that TSHs should NOT be checked in central hypothyroidism. Instead, FT4 should be followed periodically and the dose of LT4 should be adjusted to keep the FT4 in the normal range.
- The usual dose of LT4 is weight-based and is approximately 1.6 mcg/kg.
My thanks to Jon Sweet, MD, who is our Carilion Interim Chief for Hospitalist Medicine, a regular Take 3 reader, and one of the most astute clinicians I know, for his outreach to provide this clinical reminder.
Though having a single medical record has many benefits, as more clinicians have access to such a record, I am amazed and often disheartened at the “medical mythology” that shows up regularly in patient’s histories. I therefore encourage our residents to regularly review both the “problem list” and history sections of the record with a critical thinker’s eye and annotate additional history when required so errors (and the often potentially harmful results) can be avoided.
Jonkglass J et al. Guideline for the Treatment of Hypothyroidism: American Thyroid Association Task Force. Thyroid 2014. 24(12):1060-1751. Link
Mark and John
Carilion Clinic Department of Family and Community Medicine
Feel free to forward Take 3 to your colleagues. Glad to add them to the distribution list.
Follow-up: Genetic Testing Fraud (April 2nd Pointer)
As follow-up to our recent Pointer on Genetic Testing Fraud, we received the following tip from one of our colleagues, Ted Polverino, DO. NOTE that Ted has no financial interest in either company: “I felt compelled to mention that patients should avoid the genetic testing option offered via 23&Me and other popular services. These are okay to use to find out about your family tree, but the problem is this testing service is flawed for disease diagnoses as they do not do all of the needed gene sequencing. This can result in a false negative screen and put patients at risk. For those interested in genetic testing I have researched and found the Invitae screening to be the best option. This is a reputable company with great follow up and support and is used by many academic centers in the US. I usually suggest the 147 gene option for my patients who are interested. https://www.invitae.com/en/testing-options
Another solid company that’s even more affordable is a company called Color, which has a good reputation and do a good job with genetic testing for key mutations. They have decided to focus on direct to consumer and the product is available on Amazon.”