New CT Methods Detect Treatment Effects on Osteoporosis

Inoue K, Hamano T, Nago N, et al. Multidetector-row computed tomography is useful to evaluate the therapeutic effects of bisphosphonates in glucocorticoid-induced osteoporosis. J Bone Miner Metab. (2013) [Epub ahead of print]

New technology that assesses trabecular bone microarchitecture -- multidetector-row computed tomography (MDCT) -- may be better than more conventional methods for monitoring glucocorticoid-induced osteoporosis (GIO), say Japanese researchers.

A small open-label randomized trial compared the effects of vitamin treatment on bone microarchitecture with those of bisphosphonates among 15 Japanese patients with GIO (mostly men, ages 25-32), using dual energy X-ray absorptiometry (DEXA) and MDCT. The differences were obvious.  

The patients, all of whom had immunoglobulin A (IgA) nephropathy but normal renal function, had received two courses of methylprednisolone pulse therapy and subsequent oral prednisolone, a regimen which the researchers note often induces fractures even in patients with normal bone mineral density.

They divided the patients randomly into three groups, treating their GIO with either vitamin D (n=5), vitamin K2 (n=4), or a daily (alendronate) or weekly (risedronate) bisphosphonate (n=4). At baseline and six months after the start of therapy, they assessed bone condition using blood turnover markers (e.g., NTX cross-linked N-telopeptide of type I collagen), DEXA, and MDCT.
 

MDCT could detect improvements in structural indices such as bone volume fraction, trabecular separation, marrow star volume, and structure model index among those who took bisphosphonates. Neither vitamin regimen produced significant differences in these measures.

Neither bone turnover markers nor DEXA could spot significant differences between any of the treatment groups.