Bone turnover markers (CTX and P1NP): do you have a baseline?

Posted by mayblin @mayblin, Mar 27 11:05am

Currently i am on forteo therapy with a couple bone markers tests done. However, I didnt have ctx or p1np tested before the start of forteo as a baseline, regrettably.

It is known that the CTX value varies greatly among different individuals, with a very wide range. For post menopausal women, the range could be 34 - 1037 pg/ml; while for perimenopausal women 34-635 pg/ml. Different labs also have a slight different range values.

CTX, a bone resorption (breakdown) marker, is heavily influenced by a number of factors, such as food intake, circadian variation and exercise/life style, etc.

Bone remodeling is a dynamic and complex process. CTX itself may not fully reveal the whole picture. The bone building marker P1NP, is a lot less influenced by external factors. Taking both into consideration at the same time may shed more lights than looking at CTX or P1NP alone.

For those who had their CTX and P1NP tested before treatment with a bone drug, could you share the results if you don't mind? Thanks a lot!

Interested in more discussions like this? Go to the Osteoporosis & Bone Health Support Group.

@nme1985

Can you clarify I don’t understand the numbers?

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Hi nmee1985,
I just wrote a new comment where I tried to explain it better. You can jump to it here: https://connect.mayoclinic.org/comment/1099229/

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@hopefullibrarian

I apologize if my previous explanations about CTx to P1NP (CTx:P1NP) were unclear. Let me attempt to clarify here. But before I do, I'd like to share a simpler way to track treatment progress that I learned from a YouTube video from Dr. Doug Lucas posted last December.
You can watch it here: https://youtu.be/NgZf1Vu8UyM?si=elj8Y6u_bWMLY9UT

Dr. Lucas uses this equation:
P1NP ÷ (CTx ÷ 1000) = X

When the result (X) increases, it indicates you're moving in the right direction. Here are my results from January and April using this calculation:

- Before Evenity treatment (January): X = 95.5
- 2 weeks after the 3rd Evenity treatment (April): X = 287

The number went up dramatically with Evenity treatment, so I know that it's working.

Now, let me provide a clearer explanation of the 10:1 ratio:

A good ratio in this context means that for every unit increase in CTx (a marker of bone breakdown), we ideally want to see a proportional increase in P1NP (a marker of bone formation).

For instance, if the ratio is 10:1 (10 to 1), it suggests that for every 10 units of CTx, there is 1 unit of P1NP. This indicates a balance where some bone formation is occurring relative to bone breakdown.

If our goal is to increase P1NP, we should ideally see the ratio adjust accordingly. A higher ratio, like 10:2 or 10:3, would mean that for every 10 units of CTx, there are 2 or 3 units of P1NP, respectively. This higher ratio indicates more bone formation relative to bone breakdown, which is beneficial for bone health.

Therefore, a good ratio when aiming for an increase in P1NP shows a proportional or higher increase in P1NP compared to CTx, suggesting improved bone formation relative to breakdown."

I hope that's helpful. It can be a real brain twister.
If your goal is just to track treatment progress, I recommend using Dr. Doug's equation. It's far more straight-forward.

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Thank you!

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@hopefullibrarian

Hi normahorn,
I attempted to write a clearer explanation of how the ratio can be useful in a separate comment. You can jump to it here: https://connect.mayoclinic.org/comment/1099229/

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That is basically what I wrote but I did it in a simpler manner.

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@normahorn, Thank you for your much simpler explanation. I apologize for being so verbose.
It seems I may have misunderstood your point in your explanation. Could you clarify whether you meant a ratio of 10:3 indicates a worse condition (losing bone) compared to 10:1, or if it actually signifies improvement (gaining bone)? If it's the former, it appears our interpretations differ.

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@hopefullibrarian

@normahorn, Thank you for your much simpler explanation. I apologize for being so verbose.
It seems I may have misunderstood your point in your explanation. Could you clarify whether you meant a ratio of 10:3 indicates a worse condition (losing bone) compared to 10:1, or if it actually signifies improvement (gaining bone)? If it's the former, it appears our interpretations differ.

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If, and that is a big IF, the "ideal value of CTX/P1NP is 10, then a value > 10 would mean more bone is being lost than produced while a value < 10 would mean more bone is being produced than lost. Those of us with values around 4 should have fantastic bones.

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@normahorn

If, and that is a big IF, the "ideal value of CTX/P1NP is 10, then a value > 10 would mean more bone is being lost than produced while a value < 10 would mean more bone is being produced than lost. Those of us with values around 4 should have fantastic bones.

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I see what's causing this confusion. You're looking purely at the value of CTx divided by P1NP, rather than as a ratio. We're comparing apples to oranges. You are absolutely correct that when dividing CTx by P1NP "a value > 10 would mean more bone is being lost than produced while a value < 10 would mean more bone is being produced than lost." That's an interesting way to look at it, and it does work.
I was taking it a step further to represent it as a ratio which is different, and admittedly more complicated. With the ratio, the larger the number in relation to 10, the better the bone turnover.
Mystery solved!
Thank you for sharing this alternative way of looking at it.

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@melia7

to @mayblin
About frax score:

I have 4,9 for spine and 1,3 for hip.
The risedronate will be the first medicine, and Dr. said if the results will be OK, I can stop it in 3-4 years. It all depends on many factors.

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I see @melia7. Your frax scores are relatively low. Hopefully risedronate will do the trick in stopping further bone loss. Best of luck and keep us posted!

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@mayblin

@babbsjoy me too, am interested in what your endo will be commenting regarding your bone markers as well as treatment plan. Please keep us updated. Thanks a lot!

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My osteo specialist is recommending Tymlos, subject to a 24 hour urine test and insurance cooperation. I’ve reviewed what my insurance company’s parameters are for approval, and I should qualify. We will see!

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@babbsjoy

My osteo specialist is recommending Tymlos, subject to a 24 hour urine test and insurance cooperation. I’ve reviewed what my insurance company’s parameters are for approval, and I should qualify. We will see!

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Tymlos is a wonderful bone builder. Hope a smooth path and a great success ahead of you!

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@mayblin

Tymlos is a wonderful bone builder. Hope a smooth path and a great success ahead of you!

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Thank you! I am cautiously excited to have this opportunity . Grateful, but apprehensive . I’m not a big med person, and have been blessed to not to have had to take much in the past. I know this means more meds for the rest of my life—and what comes after Tymlos is more troubling. But one step at a time! I read somewhere in these posts that someone was asked, “If you had cancer would you refuse treatment because of possible side effects? “ I knew someone who did that very thing, trying to heal holistically. I was with him as he died. So this resounded with me, as I want to continue to be active and independent. (Not that meds are necessary for everyone with osteo, but given my stats it appears to be necessary for me)

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