(This post was updated 4/9/2023)
The skeptical cardiologist primarily makes decisions on blood pressure treatment these days based on patient self-monitoring.
If high readings are obtained in the office I instruct patients to use an automatic BP cuff at home and make a measurement when they first get up and again 12 hours later. After two weeks they report the values to me.
I described in detail the recommended technique in my 2018 post entitled “Optimal Home Blood Pressure Monitoring: Must The Legs Be Uncrossed and The Feet Flat?“
Although I’ve been recommending self-monitoring to my patients for decades it is only recently that guidelines have endorsed the approach and good scientific studies verified its superiority.
I was pleased when the 2017 ACC/AHA guidelines for High Blood Pressure made home self-monitoring of BP a IA recommendation.
And last year a very good study, the TASMNH4 was published which demonstrated the superiority of self-monitoring compared to usual care.
TASMINH4 was a parallel randomised controlled trial done in 142 general practices in the UK, and included hypertensive patients older than 35 years, with blood pressure higher than 140/90 mm Hg, who were willing to self-monitor their blood pressure. Patients were randomly assigned (1:1:1) to self-monitoring blood pressure (self-montoring group), to self-monitoring blood pressure with telemonitoring (telemonitoring group), or to usual care (clinic blood pressure; usual care group).
The home BP goal was 135/85 mm Hg, 5 mm Hg lower than the office BP goal. At one year both home self-monitoring groups had significantly lower systolic blood pressure than the usual care group.
This trial was not powered to detect cardiovascular outcomes, but the differences between the interventions and control in systolic blood pressure would be expected to result in around a 20% reduction in stroke risk and 10% reduction in coronary heart disease risk. Although not significantly different from each other at 12 months, blood pressure in the group using telemonitoring for medication titration became lower more quickly (at 6 months) than those self-monitoring alone, an effect which is likely to further reduce cardiovascular events and might improve longer term control.
Advantages of Home Self-Monitored Blood Pressure-Limitations of Office BPs
I described why I switched to home BPs in a post about the landmark SPRINT trial in 2015:
Every patient I see in my office gets a BP check. This is typically done by one of the office assistants who is “rooming” the patient using the classic method with , listening with stethoscope for Korotkov sounds. If the BP seems unexpectedly high or low I will recheck it myself.
Often the BP we record is significantly higher than what the patient has been getting at home or at other physician offices.
There are multiple factors that could be raising the office BP: mental stress from driving to the doctor or being hurried or physical stress from walking from the parking lot.
In addition, I feel that multiple assessments of out of office BP over the course of the day and different days are more likely representative of the BP that we are consistently exposed to rather than one reading in the doctor’s office.
Accuracy and technique in the doctor’s office is also an issue.
Interestingly, we have assumed that manual office BP measurement is superior to automatic but this recent paper found the opposite:
Automated office blood pressure readings, only when recorded properly with the patient sitting alone in a quiet place, are more accurate than office BP readings in routine clinical practice and are similar to awake ambulatory BP readings, with mean AOBP being devoid of any white coat effect.
A patient left a comment to that paper which is quite insightful:
I had a high blood pressure event several years ago. Since then I have monitored my BP at home, sitting with both feet flat on the floor, not eating or drinking, not speaking or moving around, on a chair with a back, and without clothes on the arm being used for the measure. My BP remains normal.
I have never had my BP taken correctly in a doctor’s office. They will do it while I am speaking with the doctor, sitting on an exam table with my legs swinging, with the monitor band over my heavy winter sweater, right after I have sat down. They do not ensure that my arm is supported or at the right height. If I recommend that I take off my sweater, or move to a chair with a back, they tell me that is not needed. I have decided to refuse such measurements. How can they possibly be monitoring my health this way?
This patient’s observations are not unique and I suspect the majority of office BPs have most if not all of the limitations she describes.
Self Monitoring Improves Patient Engagement In BP Control
I have found self-monitoring of patient’s BP to substantially enhance patient engagement in the process.
Self-monitoring patients are more empowered to understand the lifestyle factors which influence their BP and make positive changes. Blood pressures are amazingly dynamic and as patient’s gain understanding of what influences their BP they are going to be able to take control of it.
I take my BP almost daily and adjust my BP medications based on the readings. After prolonged work or exercise in heat, for example, BPs will decline to a point where I’m light headed or fatigued. Less BP med at this time is indicated.
Conversely, if I’ve been overly stressed BPs increase and upward titration of medication is warranted.
With some of my most engaged and enlightened patients we perform similar titrations depending on their circumstances. Sometimes patients perform these titrations on their own and tell me about them at the next office visit.
What’s The Best Way To Communicate Home BPs?
Many of my patients provide me with a hand-written record of their BPs over two weeks. Some mail them to me, others bring them in to the office. We scan these into the EMR.
I look at these and make an estimate of the average systolic blood pressure, the variation over time and the variation during the day. It’s not feasible for me or my staff to enter the numbers or precisely obtain an average.
Some patients send us the numbers through the internet-based patient portal into the EMR. This is preferable as I can view these and respond quickly and directly back to the patient with recommendations.
More and more patients are utilizing their smart phones to record and aggregate their health data and will bring them in for me to look at during an office visit. I’ve described one stylish and slick BP cuff, the QardioArm which has neither tubes nor wires and works through a smartphone app. Omron , also has multiple cuffs which communicate via BlueTooth to store data in a smartphone app.
I particularly like and often recommend the Omron Evolv (see my review here.)
Ideally, we would have a way for me to view those digitally recorded BPs with nicely calculated averages online and within the EMR. Unfortunately, such connectivity is not routinely available.
However, for my patients who are already monitoring their heart rhythms with a Kardia mobile ECG and are connected with me online through KardiaPro Remote I can view their BP recordings online.
I’ll discuss in detail in a subsequent post the Omron Evolv home automatic BP cuff (my current favorite) which is wireless and tubeless and connects seamlessly to KardiaPro allowing me to view both BP and heart rhythm (and weight) recordings in my patients
To me, this empowerment of patients to record, monitor and respond to their own physiologic parameters is the future of medicine.
From the 2017 ACC/AHA BP guidelines
and the proper technique for office BP measurement
17 thoughts on “Why I Encourage Self-Monitoring Of Blood Pressure In My Patients With High Blood Pressure”
Firstly, thanks for all your insightful posts and weeding out of poorly designed studies purporting to be real science.
As someone with family history of hypertension and a current BP of around 135/85 (at 40 years old) I’ve seen recent news reports of a study into inspiratory muscle strength training and it’s apparent (and initially unexpected) positive effect on blood pressure.
I wondered if you had seen this or had any thoughts on it’s potential (larger studies are on going I believe).
I had not heard of it but found this 2018 study which is likely what you are reference. https://www.ncbi.nlm.nih.gov/pubmed/29178489
A recent review concluded “IMT is an effective treatment for inspiratory muscle weakness in several populations and could be considered as a complementary treatment to improve the cardiovascular system, mainly HR and DBP. Further research is required to better understand the above findings.”
The review (https://www.ncbi.nlm.nih.gov/pubmed/31190975) concluded minimal benefit on systolic BP.
One more observation:
Most office/hospital robosphygmomanometers measure during deflation after having shut off the sounds. Some of these over-inflate, often painfully – causing increased BP and . . . further inflation!
Other devices measure during inflation and then deflate quickly when the job is done. Much more comfortable.
Is one more accurate than the other?
The Omron Evolv I mentioned measures during inflation and is quicker than the conventional ones that measure during deflation.
Several studies have demonstrated equivalent accuracy for the two types (https://www.ncbi.nlm.nih.gov/pubmed/19252437)
Thank you for your interesting articles, and the opportunity to contribute our personal observations.
I recently upgraded my Omron monitor to a Bluetooth model, and had a problem with erratic readings.
The helpful Omron tech advisor told me that the new model had a soft cuff, while the older model had a hard cuff.
The new model requires that it be fastened so that a finger can easily be inserted under the cuff. Quite a lot less tighter than the old hard cuff.
He also told me that left arm readings are more reliable.
The Omron monitor can give a warning of irregularities with a heart wiggle symbol. This symbol does pop up, much less often now the beta blockers have stopped PACS and PVBs. KARDIA reports all well now.
One measurement I track is the Pulse Pressure, the difference between systolic and diastolic. It is a measure of vessel stiffness. I am impressed at how exercise will drop it down should it start to drift up.
I find that the iPad app MyNetDiary Pro is excellent in tracking the myriad parameters that are involved in monitoring health.
The Apple iHealth app is excellent, but vision issues make it difficult to use. Hope one day it will be available on the iPad.
The MyNetDiary on the iPad Pro has very large fonts, so is easy to use.
It has standard trackers, for medications, blood pressure and blood glucose, plus the ability to customise your own trackers.
With a bit of ingenuity you can create a tracker that shows the correlation between 2 different parameters. Eg a reading of 73 this morning on a custom tracker would mean Condition 1 had a value of 7, and condition 2 had a reading of 3. Repeated readings, plus graphs, show the long term correlation between the two conditions. Correlation may indicate a common underlying relationship.
The app gives excellent reporting with graphs.
The act of recording measurements is well documented as the Hawthorne Effect, so that what gets measured gets managed. This is shown in many weight loss trials.
MyNetDiary has excellent food diary recording, and is well suited for diabetics, and those who have a food plan to lose weight.
The challenges is to transform data into useful information, and integrating it into a total overview. Apps can help us understand what is happening inside our bodies, so we can help maintain good health.
hmm. maybe the correct way to measure the bp is with the patient asleep. how realistic is a bp that is taken with the pt sitting motionless and not speaking with the feet flat? that event is unlikely to occur at any other time of the day. maybe the advantage to that measurement is consistency- if it’s done the same way each time. but it is doubtful that this kind of measurement reflects real life bp .
There is 24 hour ambulatory measuring, but the equipment is still bulky and it’s really sleep-disturbing.
Let’s have some bio-tech enterprise develop an aortic BP sensor implant that will communicate through a smartphone app to his cardiologist 60/60/24/365.
Or, does that exist already?
There must be a sweet spot somewhere between negligence and obsession?
Ambulatory BP monitoring is felt to be the best method available. Medicare coverage of ABPM was just expanded. Anything that directly measures the blood pressure within the arteries will require an invasive procedure and leaving a foreign body inside an artery is never a good idea as it becomes a nidus for thrombus and infection.
We can get sleep BP with an ambulatory BP device which inflates every hour (and disrupts sleep) and this method is felt to be the best correlate of cardiovascular outcomes.
However, the most patients don’t like them at all and don’t like repeating them. In contrast the home self-monitored BP is easy to repeat daily over time and most patients don’t mind doing it and most likely reflects the overall burden of BP pretty well.
I love my qardioarm and have found it easy to use and pairs with my Apple 4 watch. I have found it is easy to use at my desk when Nebulizing for my COPD 4 times a day. unfortunately neither my Pulmonary Doctor or my Cardiologist seem to want to keep track of my BP. I would think it would be a good way to check how I am reacting to new Afib medications and if they are conflicting with the other breathing Meds. Yes, I am a gadget geek and love checking them out to keep track of my 77 year old body. This looks like a no brainer for you Doc’s to watch us old folks and make a little extra money along with it for remote monitoring. https://www.getqardio.com/qardiomd-heart-health/
It should be a no brainer!
I’ve also been using my QardioArm with activation by the Apple Watch 4 and it is great.
It seems to me that Mike’s notion of “real” BP is ephemeral. As you state yourself, BP is dynamic, responding to circumstances. I suggest that the lowest safe BP you can get – doing it properly while relaxed – WITHOUT feeling light-headed, is what you should shoot for. My GP can testify to the deadliness of going lower. A patient fainted upright in a confined space and died.
Regarding your own light-headedness, I’m wondering about the half-life of your med(s). Wouldn’t you expect to come back to your normal relaxed average BP within an hour or two after exercise? Chasing around a “dynamic” BP in that way strikes me as being a bit OCD. 🙂
Naturally, one should be concerned about one’s BP. Here’s my own problem: T-shirt syndrome. I get performance anxiety even when taking my own BP. It takes getting utterly bored with repeat readings over days to get past it. There’s a point of diminishing returns in constantly keeping track.
To me, 158/92 in the doctor’s office while 118/75 at home is a good combination.
Interesting concept-“lowest safe BP you can get-doing it properly while relaxed-WITHOUT feeling light headed is what you should shoot for”
Some one should do an outcomes study with your technique versus the standard.
In general it does appear that lower is better for BP as long you are not having any low BP symptoms (fatigue, dizziness).
In my own case and for my patients I don’t recommend chasing transient BP drops or elevations. But if consistently the BP is so low during the day that you are having symptoms, then it is time to consider tweaking BP meds to adjust for this over days to weeks..
As usual, mediocre guidance from ACP who owes Dean Ornish a profound apology for inappropriate sniping at Ornish’s research. But here are my published 2 cents re home BP monitoring.:
The Journal of Clinical Hypertension Volume10, Issue11 November 2008, Pages 885-885
Re: “Call To Action on Use and Reimbursement for Home Blood Pressure Monitoring: Executive Summary”
H. Robert Silverstein MD
Published: 04 November 2008
To the Editor:
The injunction contained in “Call To Action on Use and Reimbursement for Home Blood Pressure Monitoring: Executive Summary”(1) against wrist BP monitors is arbitrary, prejudicial, lacking in clinical experience, and nonsense. Currently, there are so many people with large arms that, rather than larger cuffs, wrist monitors work uniformly well; moreover, wrist monitors fit just fine, are more convenient, are easily portable, and can be verified as accurate. The method that I use is as follows: apply the blood pressure (BP) cuff and record the BP (arm or wrist). BP is immediately measured again using my (lifetime‐certified) upper arm BP cuff. This is repeated twice in quick succession. The patient’s BP cuff and mine are used on the same arm, since there may be an important difference in readings between the two arms.
If the two cuffs measure identical readings or provide readings that are minimally different, the patient is informed of what to add or subtract from the systolic and/or diastolic values. Pickering and colleagues1 merely and inadequately state that the BP cuff is to be verified, with no specific method discussed.
This article’s recommended method for BP recording has nothing to do with the realities of life. It is ideal to see what the BP is at any time and under any circumstance, as well in the “9 times zones”: before and after each meal, in between meals, and at bedtime. These can be measured over 3 or 4 days, giving the physician a comprehensive picture of daytime and evening BP levels. This is more likely to be accomplished with the smaller and more portable wrist cuff. Sitting calmly in a near‐meditative state resembles no part of conscious life I am aware of. If the patient smokes, drinks, or exercises, I want to know what their BP numbers are(!). There is no reason to assume that these wrist monitors become inaccurate over time, and if such occurs, the discrepancy is usually obvious and readily identifiable.
A couple of observations:
1. The recommended method for BP measurement is the upper arm. See https://www.ahajournals.org/doi/pdf/10.1161/HYPERTENSIONAHA.116.07961
2. This was a “letter to the editor”, basically an opinion that contains no peer-reviewed study, thus although published it has no more credibility.
First of all thank you so much for your articles. As an engineer (and a hopeless skeptic myself) I find your information absolutely fascinating and extraordinarily helpful due to their practical and data-driven nature.
Regarding home BP monitoring, with a family history of strokes and one small NSTEMI in my past, I am a bit fanatic about daily monitoring my BP. While following the AHA guidelines on technique I have observed that some days it takes multiple readings to “wring out” the last 5-10 points in my systolic reading to get below 120. I use deep breathing and meditative techniques to become as relaxed as possible. However this begs the question, what is my “real” BP if I have to literally work at mentally getting my systolic BP down 5-10” Hg. Is it a matter of demonstrating absolute arterial elasticity? Does it matter that my “real” BP throughout the day is 10 or even 20 points higher? Neither my PCM nor my cardiologist really has an answer and simply tell me that my BP is “well controlled” and for me not to be concerned.
Sorry for the long post. Again, thanks for all the great info.
Thanks for your kind comments. I’ve added them to my section on “nice things people have said”.
I have exactly the same concerns you express.
The Achilles heel of the home self-monitoring of BP, I suspect, is that the patient selects the BP that will be recorded. Depending on how proactive they want to be about controlling the BP, and recognizing that higher BPs likely mean more BP medications, many of my patients will keep disgarding high BPs until they get the lower one they desire.
My philosophy on this is that if the patient is not giving me accurate data that is their choice and reflects how they wish to be treated. As long as they understand the benefits of tighter BP control I am ok with their decisions.