Calcium and vitamin D therapy in corticosteroid-induced bone loss: What isthe evidence?

Corticosteroid-induced osteoporosis (CIO) is a serious disorder that result s in significant long-term morbidity. Increased bone resorption is caused b y decreased Ca absorption and increased urinary Ca excretion leading to sec ondary hyperparathyroidsim. Calcium prophylaxis alone, when patients start corticosteroids, is associated with rapid rates of spinal bone loss and off ers only partial protection from corticosteroid-induced spinal bone loss. T hough calcium supplementation may have some benefit, it clearly cannot comp letely prevent corticosteroid-induced bone loss. At most, Ca therapy should only be considered adjunctive therapy in the treatment or prevention of co rticosteroid-induced bone loss and should be administered in combination wi th other treatments. Earlier work demonstrated increases in forearm bone mi neral density (BMD) with the use of Ca and vitamin D in patients with estab lished CIO. However, caution should be taken when interpreting these result s, since bone loss generally tapers or plateaus after the first 12 months o f corticosteroid treatment; as such, any therapy might show benefit. In add ition, bone density was only taken at the radius and not the spine where mo st of the bone loss takes place. Nonetheless, in recent trials of at least 2-year duration in which calcium and vitamin D therapy served as placebos, the result indicated that bone mass was maintained at the spine and hip thr oughout treatment in patients who had used chronic corticosteroids. in prim ary prevention trials, the amount of bone loss observed in the spine after therapy with Ca and vitamin D combinations is similar to that observed in o ther prevention studies in the Ca alone-treated control groups. Furthermore , Ca and vitamin D therapy appears to be less effective than other agents i n the prevention of corticosteroid-induce bone loss. Although several studi es do not report side effects that may be associated with Ca and vitamin D therapy, the few that do frequently report hypercalciuria. In the absence o f other studies that support the use of Ca and vitamin D in the Corticoster oid-Induced Osteoporosis prevention of CIO, the data are too limited to gen erally recommend them alone as a preventative therapy. Activated vitamin D may be of greater benefit.