Osteopenia, osteoporosis, the T- and Z-score

I’ve had patients who wanted an explanation on what their DEXA/bone scan result was. I wanted to understand it better myself, what is a T-score and a Z-score?

Also, just because a patient’s results may be normal or the risk of fracture in the next 10 years low, best to compare the present result with their previous DEXA/bone scan. Has their T-score considerably changed?

According to the March 2017 BC Medical Journal, to assess a patient’s risk of fracture is not by bone mineral density results alone but also:

• previous hx of fragility fractures (if it’s happened before there is a higher risk of it happening again)
• CAROC fracture risk calculator
• FRAX fracture risk calculator

The question of a “drug holiday” came up, whereby my patient asked me whether she should stop taking her bone medication as she was taking it for over 4-5 years. I learned that bisphosphonates can be safely continued past 5 years in patients who are at a mod-high risk of fracture – chronic steroid use, previous fracture, BMD less than -2.5.

Those who are low risk may have a drug holiday between 1 to 3 years.

Very cool! 🙂