Biomedical subjects

Steven T Harris

Publications and source records attributed to Steven T Harris.

5 recordsLinked to original sources

PubMed2005

Parathyroid hormone and teriparatide for the treatment of osteoporosis: a review of the evidence and suggested guidelines for its use.

All therapies currently recommended for the management of osteoporosis act mainly to inhibit bone resorption and reduce bone remodeling. PTH and its analog, teriparatide [recombinant human PTH(1-34)], represent a new class of anabolic therapies for the treatment of severe osteoporosis, having the potential to improve skeletal microarchitecture. Significant reductions in both vertebral and appendicular fracture rates have been demonstrated in the phase III trial of teriparatide, involving elderly women with at least one prevalent vertebral fracture before the onset of therapy. However, there is as yet no evidence that the antifracture efficacy of PTH will be superior to the bisphosphonates, whereas cost-utility estimates suggest that teriparatide is significantly more expensive. Teriparatide should be considered as treatment for postmenopausal women and men with severe osteoporosis, as well as for patients with established glucocorticoid-induced osteoporosis who require long-term steroid treatment. Teriparatide should also be considered for the management of individuals at particularly high risk for fractures, including subjects who are younger than age 65 and who have particularly low bone mineral density measurements (T scores < or = 3.5). Teriparatide therapy is not recommended for more than 2 yr, based, in part, on the induction of osteosarcoma in a rat model of carcinogenicity. Total daily calcium intake from both supplements and dietary sources should be limited to 1500 mg together with adequate vitamin D intake (< or =1000 U/d). Monitoring of serum calcium may be safely limited to measurement after 1 month of treatment; mild hypercalcemia may be treated by withdrawing dietary calcium supplements, reducing the dosing frequency of PTH, or both. At present, concurrent therapy with antiresorptive therapy, particularly bisphosphonates, should be avoided, although sequential therapy with such agents may consolidate the beneficial effects upon the skeleton after PTH is discontinued.

Aged↗

PubMed2005

Ibandronate produces significant, similar antifracture efficacy in North American and European women: new clinical findings from BONE.

OBJECTIVES: BONE (oral iBandronate Osteoporosis vertebral fracture trial in North America and Europe) determined whether less frequent dosing of ibandronate (dose-free interval > 2 months) provided similar antifracture efficacy to daily dosing. As osteoporosis medications must be effective across different populations, an additional objective of BONE was to investigate and report the effect of oral ibandronate in North American and European women, as described here. PATIENTS AND METHODS: BONE was a randomized, double-blind, placebo-controlled, fractureprevention study in 2946 postmenopausal women (age 55 years-80 years; > or = 5 years since menopause) with osteoporosis (low lumbar spine bone mineral density and one to four prevalent vertebral fractures [T4-L4]). Participants received daily calcium (500 mg) and vitamin D (400 IU) plus either placebo, oral daily ibandronate (2.5 mg) or oral intermittent ibandronate (20 mg every other day for 12 doses every 3 months). The efficacy and tolerability of ibandronate were assessed independently in both North American and European populations. RESULTS: Consistent, significant efficacy was observed in the North American (new vertebral fracture risk reduction: 60% and 54% with daily and intermittent ibandronate, respectively) and European patient populations (50% and 48%, respectively). Both ibandronate regimens also significantly reduced the incidence of new, worsening, and acute clinical, vertebral fractures. Daily and intermittent ibandronate significantly increased bone density at the spine in both North American (5.4% and 4.4% vs. baseline with daily and intermittent ibandronate, respectively) and European (7.1% and 6.3% vs. baseline, respectively) populations. Significant increases were also observed for total hip bone density (2.6% and 3.7% vs. baseline for daily, and 2.5% and 3.1% for intermittent; North American and European populations, respectively). Comparable, significant decreases in biochemical markers of bone turnover (reductions in urinary excretion of C-telopeptide levels of 53.5% and 67.1% vs. baseline for daily, and 50.0% and 53.8% for intermittent; North American and European populations, respectively) were also observed in both populations (p < 0.004 for all cited measurements in each ibandronate group vs. placebo). Oral ibandronate was well tolerated in both North American and European patients, with a safety profile similar to placebo. CONCLUSIONS: Oral ibandronate, administered daily or intermittently, effectively reduced vertebral fracture risk in North American and European women with postmenopausal osteoporosis. These results demonstrate the efficacy of ibandronate administered with extended dose-free intervals, regardless of patients' geographical origin. Research investigating other less frequent ibandronate regimens, such as once-monthly oral administration, is underway.

Administration, Oral↗

PubMed2002

Efficacy of raloxifene on vertebral fracture risk reduction in postmenopausal women with osteoporosis: four-year results from a randomized clinical trial.

The Multiple Outcomes of Raloxifene Evaluation trial studied 7705 postmenopausal women with osteoporosis randomized to placebo, or raloxifene 60 or 120 mg/d [JAMA 282(1999): 637]. This report assesses the efficacy of raloxifene on the long-term cumulative incidence new vertebral fractures through 4 yr. New vertebral fractures was assessed from radiographs taken at baseline, yr 2-4. The primary analysis was the cumulative incidence of new vertebral fractures through 4 yr. A posthoc analysis compared the vertebral fracture risk in yr 4 alone with that observed in the first 3 yr. The 4-yr cumulative relative risks (RR) for one or more new vertebral fractures were 0.64 [95% confidence interval (CI) 0.53, 0.76] with raloxifene 60 mg/d and 0.57 (95% CI 0.48, 0.69) with raloxifene 120 mg/d. In yr 4 alone, raloxifene 60 mg/d reduced the new vertebral fracture risk by 39% [RR 0.61 (95% CI 0.43, 0.88)], which was not found to be significantly different from the RR observed in the first 3 yr in both raloxifene groups, irrespective of prevalent fracture status. The nonvertebral fracture risk was not significantly reduced [RR 0.93 (95% CI 0.81, 1.06)]. The safety profile after 4 yr was similar to that observed after 3 yr. Raloxifene 60 and 120 mg/d through 4 yr decreased the cumulative risk of new vertebral fractures in postmenopausal women with osteoporosis. The decreased vertebral fracture risk in yr 4 alone was not different from that observed in the first 3 yr.

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PubMedDate not supplied

Classification algorithms for hip fracture prediction based on recursive partitioning methods.

This article presents 2 modifications to the classification and regression tree. The authors improved the robustness of a split in the test sample approach and developed a cost-saving classification algorithm by selecting noninferior to the optimum splits from variables with lower cost or being used in parent splits. The new algorithm was illustrated by 43 predictive variables for 5-year hip fracture previously documented in the Study of Osteoporotic Fractures. The authors generated the robust optimum classification rule without consideration of classification variable costs and then generated an alternative cost-saving rule with equivalent diagnostic utility. A 6-fold cross-validation study proved that the cost-saving alternative classification is statistically noninferior to the optimal one. Their modified classification and regression tree algorithm can be useful in clinical applications. A dual X-ray absorptiometry hip scan and information from clinical examinations can identify subjects with elevated 5-year hip fracture risk without loss of efficiency to more costly and complicated algorithms.

Absorptiometry, Photon↗

PubMedDate not supplied

Clinical use of teriparatide in the real world: initial insights.

OBJECTIVE: To summarize expert opinion regarding clinical application of the recently introduced anabolic agent teriparatide [human parathyroid hormone (1-34)] in treatment of postmenopausal osteoporosis in women, and osteoporosis in men. SUMMARY: The anabolic agent teriparatide was approved for clinical use by the Food and Drug Administration (FDA) on November 26, 2002. Since the launch of teriparatide, many more questions about clinical use of this exciting agent have emerged than there are answers provided by clinical trials or FDA-approved product labeling. A group of physicians with a broad range of experience in research and clinical applications of teriparatide met recently to address practical issues related to its use. This manuscript is a compendium of the consensus opinions of the authors that attempts to provide practical answers to many real-world questions being asked about teriparatide therapy since its approval by the FDA.

Anabolic Agents↗