between the data points

[pellicle]

Hi

My INR has been bumping along between 2.5 and 2.8 for a while and I have been following a routine of taking my warfarin at 7pm and having an alternating dose of 7 / 7.5 to maintain my INR.

I test weekly on Saturday mornings.

The other day I felt a bit funny and thought I'd use that as an excuse to just check my INR. I had sort of over ordered my strips and so have been more casual about doing (what I call ) ad hoc monitoring between the weekly tests.

When I measured I was surprised to see that my INR was 3.4 (on the Thursday). So I scratched my head and thought about my doses a bit. My strategy had seen me changing my alternation pattern to being 7.5 on Mon, Wed and Fri. Leaving me Sat and Sun as 7 (thus two consecutive days of 7), but otherwise alternating. This of course means that my warfarin levels settle that tiny bit lower than a perfect series of alternations. Its my way of fine tuning.

Well I decided to bump my Friday 7.5 back to 7 daily and measure again every day till (and including) Saturday. The results were interesting.

Thur = 3.4
Fri = 3.1
Sat = 2.8
Sun = 2.7
Mon = 2.7

Putting the Saturday reading back into weekly context the "spike" did not exist and my readings bumped along fine seeming quite stable. It is only with the extra knowledge I obtained by sampling within a smaller time frame that revealed there was a bit more variation in my actuals on a day by day basis.

I post this to lend support to the argument that Protimenow is always making (and which I agree with) that monthly sampling is inadequate, even if the numbers are "in range" you don't know what happened either side of that sample.

Of course it is all about risk management. Even if you are under range significantly for a few days does not mean that you will have an issue. It simply increases the chances. Its worth considering the results from one of the early On-X investigations which showed that even a significant cohort who had "none or inadequate" anti-coagulation therapy did not have any dire consequences after some years.

The advantage of home testing is that you can test more easily and conveniently than going to a clinic and getting a blood draw. Particularly for those of us who have had quite enough vein draws recently (thank you) it enables us to stay within range, maximising the benefits of the therapy and minimising the risks.

 

[chaconne]

In my limited experience with INR testing (~7 months), it seems that my INR fluctuates, mostly in range, for no apparent reason. I eat a steady diet and take 5mg/day except for 7.5 on Wed and Fri. I tested a few times on Sunday night and Wednesday night expecting to see my INR elevated on Sunday and low on Wednesday. After doing this a few times, my INR was the same, or alternatively high or low on Sun or Wed for no apparent reason. About 80-90% of my tests show close to 3. I've been as low as 2.2 and as high as 3.8.

My conclusion is that it's nearly impossible for me to know what causes these relatively small changes in INR. As long as I'm able to keep my InRatio2 reporting around 3 most of the time, I'm reasonably confident that I'm in range.

 

[pellicle]

Hi

But do you test weekly or monthly?

I take 5mg/day except for 7.5 on Wed and Fri. I tested a few times on Sunday night and Wednesday night expecting to see my INR elevated on Sunday and low on Wednesday.

Out of interest why did you expect to see elevated in Sunday?

 

[Protimenow]

Having reasonable confidence that you're in range is an important thing.

In the past, I've also gone with slightly different doses on different days (one of my plans was to take one dose on days with a T in them, and the other dose on other days). If you do this, your INR SHOULD be different, depending on which day you test - if ALL other factors were EXACTLY the same. Alternating between 7 and 7.5 makes sense - but if you do like I did in my distant past (before I knew better) and do 7.5 on two or three days and 5 on the others, it would make more sense to try and get a daily average dose that is consistent from day to day.

I've used the InRatio and InRatio 2. In my experience, the results are always higher than actual. I had a TIA, in part, because I trusted my InRatio results to be absolutely correct. For myself, if I didn't have other meters, I would probably feel 'reasonably confident' that my INR was in range (2.5 - 3.5) if the InRatio results were 3.0-4.0.

As far as balancing the risk -- I'm not exactly sure how many days you can allow your INR to be below 2.0 and not risk having an 'event.' In my case, it was probably less than a week, although others can go longer without issues. (In the not so distant past, before I was regularly testing, I had a 'wart' on my face that disappeared when I increased my warfarin dosage -- that 'wart' was, as far as I can tell, a clot that resulted from under-anticoagulating and that, perhaps, saved my life by catching any clots before they got to my brain. I'm glad that I was spared, but without regular testing back then, who knows if my theory is right or not?)

Because my life DOES depend on proper anticoagulation, I test every week to 10 days - usually testing on the same day each week. For $5 or so each week, it's cheap insurance.

 

[dick0236]

I also agree that testing frequently has a positive impact on INR management. MY INR range is 2.5-3.5 and normally "floats" somewhere within that range, although I infrequently get readings above, or below, my range. Weekly testing allows me to "tweak" my INR, usually by slightly changing my diet, if I see I'm above, or below, my range.....and I seldom have to make changes to my warfarin dosing. It also allows me to spot "trends" which may indicate a need to change my normal dose. Weekly testing makes it much easier to spot any INR trends.

Weekly testing in a lab, or docs office, is a "pain" and can sometimes get expensive. Unfortunately, in the US, many insurers and doctors, cannot, or will not, permit "self-testing". My doc knows I have the experience to do it, but because of "liability issues" cannot permit it....so I test weekly at my expense($5) and go to his office for a monthly test that is covered by insurance. BTW, one of my weekly tests is on the same day as my monthly lab test and we SELDOM agree.

I can understand that many "newbies" get the impression that we "mechanical people" are obsessed with this INR stuff. Not so.....it's just necessary because of a the warfarin nonsense that is "floating" around. Ask any experienced warfarin user and you will find that the only "must do" rules to follow are....."take your warfarin as prescribed and test routinely" and your risk of problems is only slightly above average....but SCREW around with warfarin and it can bite you....at least that is my experience.

 

[chaconne]

Pellicle,

I test weekly and get compare with a lab draw every 1-2 months. My 4 lab draw comparisons have averaged +- 0.1. Since my high doses are on Wednes and Friday, I expect to see their effect 2-3 days later which I'm assuming is Sunday or Monday.

 

[Protimenow]

Dick:

I have an 'anticoagulation clinic' that relies on monthly testing. I STILL test every week, using my own meter(s). If you trust your meter--and there's little reason why you shouldn't, consider avoiding the expense of weekly lab tests and use your meter for the weekly test, satisfying your narrow-minded doctor with a monthly blood draw. The fact that this doctor may not know that you self-test weekly is probably of minimal concern as far as your health goes. Your strategy of staying with a consistent dosage and perhaps adjusting with minor dietary changes is a good one. You really don't need weekly blood draws to know that you are - or aren't - in range. But I strongly recommend (and you already agree) doing a weekly INR test -- whether it's done conveniently at home or expensively at a lab or doctor's office - is up to you.

 

[dick0236]

Dick:
........ little reason why you shouldn't, consider avoiding the expense of weekly lab tests and use your meter for the weekly test, satisfying your narrow-minded doctor with a monthly blood draw. .

You misunderstood my post.....my fault. I self-test(at home) weekly and only go to the docs lab monthly(for a lab stic)......and in his defense, he is an employee of a hospital owned physicians group, and the hospital policy(not his) is INR management MUST be monitored by them. I don't really mind going in for a monthly lab as it is a cross check of my meter.......and their lab tech is kinda cute LOL.

 

[pellicle]

that we "mechanical people"

That's a cute expression

but SCREW around with warfarin and it can bite you....at least that is my experience.

Definitely. Like fishtailing a car. Over do the corrections and you do a 180

 

[pellicle]

Hi

I test weekly and get compare with a lab draw every 1-2 months

Wow, thats great! Regular testing and frequent "calibration" checks

Much better than me, I just do weekly testing and check with labs every 6 months.

Since my high doses are on Wednes and Friday, I expect to see their effect 2-3 days later which I'm assuming is Sunday or Monday.

Reasonable and a common view, but with warfarin half life being 20 or so hours I'd expect to see the peak a bit sooner

 

[Protimenow]

Dick, I guess that I DID misunderstand your post. Right now, for as long as I can get coverage, I also go for a monthly blood draw.

The Anticoagulation clinic is controlled by a university (it's part of a teaching hospital) that is somehow comfortable with monthly blood draws. For me, the purpose of these blood draws is basically just to confirm that my meter(s) are giving me values that are similar to the hospital lab's results. I trust my meters to keep me in range..and don't plan to ever again be comfortable relying on a monthly 'snapshot' of my INR at that specific instant during the month.

Having a cute lab tech certainly helps -- too bad I don't think I've ever seen the same phlebotomist twice, and I don't recall any of them being what I would call 'cute.'

 

[marc_kowal]

Weekly testing in a lab, or docs office, is a "pain" and can sometimes get expensive. Unfortunately, in the US, many insurers and doctors, cannot, or will not, permit "self-testing". My doc knows I have the experience to do it, but because of "liability issues" cannot permit it....so I test weekly at my expense($5) and go to his office for a monthly test that is covered by insurance. BTW, one of my weekly tests is on the same day as my monthly lab test and we SELDOM agree.QUOTE]

My cardiologist technically manages my INR management, but he wrote me the script to get a self-test machine. Just have to call into the Alere with the results. I fail to see what "liability issues" your doctor would have, as self-testing is becoming more of the norm.

 

[dick0236]

My cardiologist technically manages my INR management, but he wrote me the script to get a self-test machine. Just have to call into the Alere with the results. I fail to see what "liability issues" your doctor would have, as self-testing is becoming more of the norm.

I think the "liability" can arise when people self-test without informing their docs of INR results and then expect that doc to write scripts for their warfarin renewals even tho he has little, or no, INR history. In the "law suit environment" of the US, I can understand his caution when dealing with a drug like warfarin. As long as he tests my INR routinely, he has medical records to justify his medical handling of my warfarin needs.

Even tho you are self-testing, you are calling Alere with the result and they are calling the result in to your doc. Alere is just acting as an authorized "middle man". I used the Alere program for a year or so and decided their program was not to my liking. BTW, self-testing is a long way from becoming the norm. To my knowledge, it is only authorized for mechanical valve patients and we represent less than 10% of warfarin users. However, I do agree that it is becoming more appealing to those of us that should be monitoring our INR more frequently.

 

[Protimenow]

I think that it's more of a risk - and a liability - for doctors to be satisfied with monthly - or bi-monthly INRs. They have no idea WHAT the patient's INR is between tests. They have no idea if the patient is taking the warfarin properly (proper dose, daily, etc.) -- but to be fair, doctors have to rely on patients to follow their orders no matter what medications they take.

For myself, I keep what I call an 'INR Diary' - a spreadsheet that shows my dosage, my INR and prothrombin time (If the lab gives me both), which meter I use, time and date of testing, and any other possible factors that may have some relevance in relation to my INR. If I am EVER asked by a doctor whether or not I know what I'm doing, I can bring a copy of the diary as proof.

I've encouraged others to maintain a similar spreadsheet -- not only to follow personal INRs and testing, but as a historical record of your dosing and possible response to any changes in your diet, over the counter medications, or dosing.

I suspect that a doctor who is satisfied with monthly testing would be MORE LIABLE if something goes wrong than a doctor who supports and encourages weekly self-testing and more active monitoring and, if necessary, minor dosing adjustments.

 

[pellicle]

Hi

I think the "liability" can arise when people self-test without informing their docs of INR results and then expect that doc to write scripts for their warfarin renewals even tho he has little, or no, INR history. In the "law suit environment" of the US, I can understand his caution when dealing with a drug like warfarin.

I agree.

I would think that it also goes like this:
- something happens and some previously reasonable seeming patient perceives that they were harmed by their warfarin dose
- a lawyer is involved and the Dr needs to spend time and money defending his claim (perhaps that money is supplied by his indemnity insurance, so then they call the shots on what he does)
- some long and drawn out case eventually clears the Dr of liability

The Doctor thinks about the above scenario and thinks "nah, bugger that, not worth the hassle" and says to the patient no, you can't self manage.

That is perhaps the risk as the Dr sees it, and the insurance companies see it.

 

[Protimenow]

That scenario makes little sense, at this time.

It can also probably be argued that a doctor who adopts a once a month, or once every two month testing protocol, and who has a patient who suffers a stroke or hemorrhagic issue, can also be considered liable if an attorney finds other published protocols that call for more frequent testing.

13 years ago, my cardiologist wanted testing every other week.

There are published papers that document results that say weekly testing (including patient self-testing) provides more time in range for patients than does monthly or bi-monthly testing. In light of these published reports, it can probably be argued that a doctor provided INADEQUATE CARE for patients who were able and willing to self-test.

In many ways, putting the testing and reporting into the hands of the patient should REDUCE the doctor's liability, because the patient is taking some degree of responsibility for his or her own INR. Dosing instructions would still come from the doctor. Patient compliance will always be an issue -- is the patient following the doctor's instructions or is the patient self-managing the dosing?

I think that, once doctors are aware of the studies showing that those patients who test weekly are actually SAFER than those with monthly or even less frequent testing, the issue of liability in the mind of the doctor might change towards patient self-testing and more frequent management.

Yes. The United States can be very litigious -- but with recent study results, it can become clear to doctors that they are at risk if they do NOT allow patients to regularly self-test or if they DISCOURAGE weekly testing.

 

[pellicle]

That scenario makes little sense, at this time

My personal experience with the findings of courts and the operations of the legal system is that in general it makes little sense. Let me give you an example

I was riding on my motorcycle one evening when a policeman pulled me over after I left an intersection. He said that I did not stop at the stop sign. I said that I did and he said "well, we'll see you in court then"

At the court the officer stated that he observed that I failed to stop. I replied that not only did I stop but I stopped twice, because I rolled back slightly before taking off.

The judge asked the officer if he had seen me roll back to which he answered "yes, but he didn't put his foot down, and you can't stop a motorcycle without putting your foot down."

I said that for one I ride motorcycle trials and stopping without putting your foot down is what you need to do to get points in a section. Further I said that it was physically impossible to go from a forward direction to backwards without stopping."

The judge asked me if I had any qualifications to back that assertion. I answered that I have a degree in science from the XXX university. The judge asked was my degree in physics? I said no, it was biochemistry.

So the judge in said that in the eyes of the court I had no recognised qualification in physics and so the observations of the police officer would stand.

So I was found guilty.

I thus learned a lot about the legal system. To this day I read of incomprehensible decisions by courts weekly. My view is at whoever has the most expensive legal team will be found in favour of.

Thus doctors are quite likely cautious.

 

[pellicle]

It can also probably be argued that a doctor who adopts a once a month, or once every two month testing protocol, and who has a patient who suffers a stroke or hemorrhagic issue, can also be considered liable if an attorney finds other published protocols that call for more frequent testing.

It certainly can.

If you win that argument or not is uncertain.

 

[dick0236]

That scenario makes little sense, at this time........
........I think that, once doctors are aware of the studies showing that those patients who test weekly are actually SAFER than those with monthly or even less frequent testing, the issue of liability in the mind of the doctor might change towards patient self-testing and more frequent management.
.

I agree that knowledgeable patients, such as those on this valve forum, can easily monitor their INR. The doctors problem is identifying those who can, or cannot, be trusted to self-monitor. The vast majority of people on warfarin are senior(like me LOL)...or older LOL and many could not, or should not, attempt self-monitoring.....like a couple of my neighbors. One is 95, very frail, and has hers monitored by an "traveling nurse" and the other is an 84 year old man who hasn't the foggiest idea of why any kind of monitoring is necessary.....both are "non-valve" warfarin users......and represent, I imagine, the majority of ER patients that have given warfarin such a bad reputation. I am not deriding my own generation, but fact is fact. I can see a time, hopefully WAY down the road, that I may have trouble self-testing.

Self-testing is fairly new. I only stumbled on it about seven years ago even tho I had been getting "finger sticks" since the early '90s. Until it is universally accepted the best you can do is show your doc that you are responsible enough to self-test....'cause we experienced warfarin users know "it is not rocket science".

As Pellicle outlined, there are a bunch of "ambulance chasing" lawyers that continuously look for "class action" lawsuits......I see several "medical class action" ads on cable TV every week. While some may be justified, many are not....and the attorneys realize that they can often get settlements whether the cases are justified or not. I've already seen a class action suite ad against one of the new anti-coagulant drugs that are for non-heart valve users.

 

[Protimenow]

Dick:

You're absolutely right about some people not being good candidates for self-testing. Assessing the ability of the patient to reliably - and correctly - self-test is an important part of the approval process. Although some physicians don't want to try to assess the ability of a patient to self-test, some can fairly easily tell whether a person can or can't do the testing. (In fact, if an office had a test setup, and administered tests at the office, couldn't they try to demonstrate/train a patient, and then see if the patient would be able to follow the instructions? An In-Office, hands-on test could be useful for assessing who can, or can't do a self-test).

I would imagine, too, that for patients who are on medicare, the percentage of people who would be able to self-test would be lower than the percentage for those younger patients.

HOWEVER - I don't think that the argument that people who can't self-test are okay being tested monthly or even less often can safely do so. There are home health nurses (though the service isn't free) who should be able to quickly do a test at the patient's home; a percentage of these seniors are already in facilities where it should be simple to do a fingerstick test; and if testing was made more readily available and affordable to anyone on warfarin, the issue of testing frequencies should become moot.

Yes, Pellicle, the legal system is screwy. It's become ridiculously litigious; its lawyers somehow pass the Bar but still don't seem to have the ability to write, spell, or recognize logic (I'm talking from recent experience); and the U.S. doctors are PETREFIED by the potential of litigation. This stupid system even forces insurers into caregivers by putting medical decisions into the hands of the actuaries, rather than the caregivers.