Has anyone e lost bone mass while on Forteo?

I wonder if it's the technician. Minor differences in positioning can change the outcome. Did your doctor tell you anything?

redlo, hip and femur scores or spine? Positioning can give in inaccurate reading. That drop would be unlikely after six months of Forteo, unless you have a secondary cause of osteoporosis.
I had a dissimilar situation two different machines. I think it was because the second scan captured the area were radiation treatment had passed through the hip leaving edema and fat tissue.
Dxa should be reimaged given the anamoly.
If your osteoporosis were caused by the parathyroid and you wouldn't want to increase PTH levels with Forteo, you'd want to remedy the parathyroid issue before resuming Forteo.
Was the second dxa to determine the effect of Forteo. Are you using bone markers as well.
I'd be guessing that the numbers are a problem with the scan, but not taking any chances with other cause.

Thank you for responding. Yes it was my spine that dropped from -2.9 to -3.1
I did have surgery on my L4 to relieve leg pain in
June. Could it be inactive wearing back brace and no exercise? I just had high hopes for Forteo. The drop in dexa score scared me it miht be the drug. I go in for my 3 month blood test in Dec. To monitor how my system is handling Forteo. Just took me off guard. Thank you all for being there. I have learned so much.

Hi @redlo your experience resonates with me. I was in a similar situation when my DXA scan came back after 13mo on Forteo. The results showed good improvements in spine and TBS score; my bone markers indicated a great response to Forteo too. However, my hip bmd had a whopping 7.6% drop in just 13mo! The conflicting results did not make any sense! My DXA results ended up being re-examined. Technical errors were found and it turned out the hip bmd did not change during first 13mo on Forteo. When I finished Forteo treatment, my hips (r/l) had 5.7%/3.6% bmd increase, both "significant with 95% confidence". TBS score improved as well to a level thats within normal range.

Sometimes 6mo treatment of Forteo may not be long enough to give meanful bmd changes. You could look for LSC (least significant change) - usually in DXA report's footnote if you have them. In my report, the LSC is expressed in (numerical number) g/cm^2 for bmd. So instead of comparing T scores, we could compare the differences in bmd (before and after). If the difference is greater than the LSC, then the % change in bmd is signicant hence your Tscore too. Otherwise, there is nothing to worry about even with your slight decrease in T score which could be just variations in scan readings.

All the best to you!

Thank you so much for sharing. I live in a rual area and I don't get much
from the doctors. This group is such a blessing and a wealth of
information. I will give the Forteo more time and maybe do another Dexa in
6 more months. Thank you so much for replying.

I'd like to add that I have several T score changes of 0.2 (up or down) at different bone sites in my 3 annual DXA reports (same machine same tech). If they are clinically significant, an asterisk (*) was indicated right next to the bmd %change. It's interesting that one 3.6% change (with Tscore change of 0.2) in bmd is "significant with 95% confidence" while the other 3.6% bmd change is not. A closer look showed they are for different skeletal sites and LSCs are different.

Your original post of T score change from -2.9 to -3.5 appeared to be large but you had corrected later as -2.9 to -3.1. I definitely hope it is the latter. Double check to see if 4% change in bmd is signifcant if you have LSC info. There are talks about the common mistakes when scanning Lspine. One of which is scanning L2-L5 by mistake instead of L1-L4 according to books and online information. If this is what happened then a rescan could be warranted.

Checking bone turnover markers as @gently pointed out is one way to monitor if an anabolic such as Forteo is working well in early months of treatment. At 6mo of therapy, it is a good time to do a lab. Medical care in a rural area could be a challenge. It won't hurt to communicate with your doctor though. Some of the members on this forum use P1NP and CTX. There are threads discussing pros vs cons of bone markers and steps to take to ensure a more accurate reading. In case the managing doctor is not into bone markers, we as patients could order the lab online ourselves (by paying out of pocket 🙁 ). There is a thread for this info with ordering codes and costs. The drawback in your case might be that you might not have a baseline (me either) prior to Forteo therapy. The variability in bone turnover markers due to premetrologic and metrological causes could also make the results hard to interpret.

mayblin, if the bone markers at 6 months of Forteo indicated high CTX and low P1NP might a person suspect that they might not be on the best medication for their situation even without a baseline.

Thank you for responding. You are correct. My original post was -2.9 to -3.5
I in error, was comparing my previous - 2.9, which was my total average Lumbar score. This new scan broke out level L1 L 2 L 3 and 4 and gave me a total average lumbar score of a negative 3.1 with a negative 4%*
decrease in bmd (with an asterisk.)
I mistakly pick the -L4 of -3.5. The previous Dexa only gave my the lumbar average(-2.9)
I did get CTX and P1NP before Forteo but I had just got off of 8 months on Fosamax.So I am not sure how to interpret the result. CTX 99, P1NP 19.8 I go in for my blood work tomorrow.,but I can't get Into Dr until December .
Love this group. My primary Dr actually laughed at me when I requested CTX and P1np. I had to request a referral to endocrinologist who ordered it but did not hold much stock in the results. Could not even tell me if my numbers were good or bad.It was Dr McCormick that told me to demand off Fosamax and get on Forteo or Tymlos.

redlo,
say, if your are repeating the bonemarkers be sure and fast and have an early draw. I'll be curious about the markers because they will indicate whether Fosamax is still blunting the effect of Forteo.

After eight months on Fosamax, the response to Forteo would be stymied.
Fosamax works by stopping the natural process of bone growth which initially breaks bone down. Bone building cells (osteoblasts) stimulated by Forteo depend upon the cells (inhibited by Fosamax) to prepare the bone for a layer of new bone.
P1NP isn't as useful after a bisphosphonate. CTX is helpful to determine if Foxamax has effectively lowered the amount of bone being broken down. The next set of labs will be more interesting.

This would not be a characteristic pattern of btms in early months of forteo treatment, although one can only tell for sure when there is a baseline for comparison. When this happens, it's important to rule out underlying pathologies contributing to bone turnover derangements. Getting the secondary cause of bone loss under control is key to ensure the success of an anabolic treatment.