When treating patients with low bone mineral density, when/how do you monitor bone turnover markers (NTX, CTX, etc)?

It is a bit difficult to answer this question without more information.

If you are monitoring a patient during a drug holiday, I would order a CTX-1 and PINP when discontinuing the bisphosphonate and then again after one year. If the levels have increased over 50% from the year before that would trigger a DEXA measurement and evaluation for secondary causes of osteoporosis.

I do not order bone turnover markers for patients on anti-resorptive agents on a regular basis because the correlation between BMD change and bone turnover markers is low.

If I start a patient on a PTH anabolic therapy, I will order CTX-1 and PINP before the patient begins and then after 6 weeks. If the PINP does not increase by more than 50%, then the patient is either...