DEXA challenge: Find the errors

It seems that at least one in 10 or maybe one in 20 DEXA scan reports that I read contain some typographical error regarding the reporting of T scores or BMD. It is important to recognize, because I have seen patients' therapy changed/started/stopped by referring physicians based on erroneous results that were missed. See if you can spot the errors here. I have called the radiologists to confirm the errors. There were two that I found.

Long Term follow up of Asymptomatic Hyperparathyroidism

J Clin Endocrinol Metab. 2008 Sep;93(9):3462-70.

A must review for any general Endocrinologist who treats hyperparathyroidism - which is most. Briefly: 116 patients with PHPT (66 post-menopausal F, 25 pre-menopausal F, 25 men) were studied. 59 patients had surgery (50 asymptomatic[asx], 9 symptomatic) and 57 did not have surgery (29 had not met surgical criteria[sc], 20 met sc but refused surgery).

A picture tells a thousand words. Above: the observation graph shows those who did not have surgery over a 15 year period (n = number of patients remaining in the study), the parathyroidectomy group obviously had the surgery. Z scores are compared. (*p<0.05 compared to baseline)

Baseline calcium (10.5 vs 10.8), PTH (116 vs 144), Z score lumb spine (-0.03 vs -0.8), and Z score fem neck (-0.63 vs -1.22) differed significantly at baseline between the no surgery vs surgical group.

Notably in those followed without surgery, calcium was signigicantly higher at year 15 vs baseline (11.1 vs 10.5), but not PTH or urinary calcium.

Unfortunately, the numbers are too small to draw any meaningful conclusions about fracture rates. This change in DEXA scores is food for thought though when deciding about surgical parathyroidectomy for asymptomatic patients. It would have been nice to see the changes in BMD split out for post-menopausal, pre-menopausal and men.

Screen for osteoporosis and colon cancer - at the same time?

Found these links in the Endocrine Daily briefing from the Endocrine Society. Interesting pair of news articles describes how CT colonography can also be used to measure bone density.

"The results of the study on 35 people showed the data from the CT colonography images agreed with the subject's DEXA bone mineral density scores normally used to check for osteoporosis."

See news articles in:
Health Day
Medical Page Today

What happens to endogenous PTH during teriparatide therapy?

I've often wondered this. Fortunately, there's a study:

Endocrine Journal Vol. 55 (2008) , No. 3 613-616



36 post-menopausal women with established osteoporosis received teriparatide 20 mcg daily for 18 months and then were followed for another 6 months. You can see that iPTH significantly declines for months 6-18. There was actually no significant increase in calcium.

The authors mention this as a potential way to monitor compliance. I have wondered if teriparatide could be used to treat osteoporosis in patients with mild asymptomatic primary hyperparathyroidism or even secondary hyperparathyroidism. I had assumed that the PTH would be additive and risk driving calcium higher. In fact it may possibly lower PTH in these conditions. That would be an interesting study...