Prednisone-induced bone loss
A 68-year-old woman was admitted to your hospital with fractures of her right sixth and seventh ribs and right wrist following an automobile accident. Her medications on admission included prednisone 5 mg (polymyalgia rheumaticaduration 12 months), hydrochlorothiazide 25 mg, and omeprazole 20 mg per day. While in the hospital, a dual-energy X-ray absorptiometry (DXA) study showed the patient's femoral neck bone density to be 2.5 standard deviations below normal. She will be dismissed on the same medications as at admission (with increased prednisone) and oxycodone 5 mg/acetaminophen 500 mg. However, the physician recognizes the need to treat osteoporosis. What do you suggest and why?
This patient's osteoporosis is most likely due to a combination of age-related factors and long-term glucocorticoid therapy. To minimize bone loss, prednisone should be tapered to the lowest dose that will effectively manage the symptoms of polymyalgia rheumatica.
According to the American College of Rheumatology, patients receiving a prednisone equivalent of >= 5 mg/day with a T-score below 1 should take a bisphosphonate. If omeprazole use is indicative of esophageal abnormalities or the patient has other contraindications to alendronate, calcitonin is a second-line consideration. Therapy should continue as long as this patient is taking prednisone. Monitor bone mineral density every six to 12 months.
I'd recommend supplementation with 1500 mg of elemental calcium and 400 IU of vitamin D daily. Calcium citrate may be a preferred option in this patient due to decreased gastric acidity. Cessation of smoking and limitation of alcohol and caffeine intake should be encouraged. Weight-bearing activities can increase bone mineral density and should be added as tolerated.
Treatment options include HRT, raloxifene, calcitonin, and bisphosphonates. HRT reduces nonvertebral and vertebral fractures by 23% and 33% in five years, respectively. However, a recent controversial study demonstrated a modest increase in breast cancer, and one arm of the study was stopped prematurely because of increased risk of cardiovascular side effects.
Raloxifene reduces vertebral fracture risk by 55% over three years. Calcitonin is considered less effective, with no fracture-reduction data. Both alendronate and risedronate are approved for the treatment of osteoporosis and glucocorticoid-induced osteoporosis. They decrease the risk of spine, hip, and wrist fractures by 40%-50% over five years. In glucocorticoid-induced osteoporosis, vertebral fractures were reduced by 90% over two years of treatment with alendronate and 66% over one year of treatment with risedronate.
Bisphosphonates are the best choice for this patient even though her previous prednisone dose was < 7.5 mg/day. Regardless of future doses, bisphosphonates are optimal since they've demonstrated reduction of risk for both vertebral and nonvertebral fractures in the treatment of osteoporosis. Adequate calcium and vitamin D intake are essential with bisphosphonates.
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Kathy Hitchens. Prednisone-induced bone loss. Drug Topics 2002;18:HSE27.