Antifracture efficacy of currently available therapies for postmenopausal
osteoporosis.
Author(s): Reginster JY.
Affiliation(s): Bone and Cartilage Metabolism Research Unit, CHU Centre - Ville, Liege, Belgium.
jyreginster@ulg.ac.be
Publication date & source: 2011, Drugs. , 71(1):65-78
Osteoporosis is a systemic bone disease characterized by low bone mass and bone
mineral density, and deterioration of the underlying structure of bone tissue.
These changes lead to an increase in bone fragility and an increased risk for
fracture, which are the clinical consequences of osteoporosis. The classical
triad for consideration in osteoporosis is morbidity, mortality and cost.
Vertebral fracture is an important source of morbidity in terms of pain and
spinal deformity. On the other hand, hip fracture is associated with the worst
outcomes and is widely regarded as a life-threatening event in the elderly; it is
the source of the bulk of the cost of the disease in contemporary healthcare. The
prevention of osteoporosis-associated fracture should include fall prevention,
calcium supplementation and lifestyle advice, as well as pharmacological therapy
using agents with proven antifracture efficacy. The most commonly used
osteoporosis treatments in Europe are the bisphosphonates alendronate,
risedronate, ibandronate and zoledronic acid; the selective estrogen receptor
modulator (SERM) raloxifene; teriparatide; and strontium ranelate. Recent
additions include the biological therapy denosumab and the SERM bazedoxifene. In
this review, we explore the antifracture efficacy of these agents with the aim of
simplifying treatment decisions. These treatments can be broadly divided
according to their mode of action. The antiresorptive agents include the
bisphosphonates, the SERMs and denosumab, while the bone-forming agents include
parathyroid hormone and teriparatide. Strontium ranelate appears to combine both
antiresorptive and anabolic activities. We collated data on vertebral and hip
fracture efficacy from the pivotal 3-year phase III trials, all of which had a
randomized, double-blind, placebo-controlled design. The relative reductions in
risk in the osteoporosis trials range from 30% to 70% for vertebral fracture and
30% to 51% for hip fracture. This translates into 3-year number needed to treat
values of between 9 and 21 for vertebral fracture and from 48 upwards for hip
fracture. International guidelines agree that agents that have been shown to
decrease vertebral, nonvertebral and hip fractures should be used preferentially
over agents that only demonstrate vertebral antifracture efficacy. This is the
case for alendronate, risedronate, zoledronic acid, denosumab and strontium
ranelate. Finally, therapeutic decisions should be based on a balance between
benefits and risks of treatment, which must be carefully considered in each
particular case both by the physician and the patient. Indeed, no single agent is
appropriate for all patients and, therefore, treatment decisions should be made
on an individual basis, taking into account all measures of treatment effect and
risk before making informed judgments about the best individual treatment option.
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