Hinze Alicia M, Louie Grant H
Division of Rheumatology, Johns Hopkins University School of Medicine, 5200 Eastern Avenue, MFL Building, Center Tower, Suite 4100, Baltimore, MD, 21224.
Curr Treatm Opt Rheumatol. 2016 Dec;2(4):271-282. doi: 10.1007/s40674-016-0055-6. Epub 2016 Oct 5.
Low bone mineral density (BMD) is increasingly recognized as a common comorbid condition in ankylosing spondylitis (AS). As low BMD increases fracture risk, it is important to identify and treat low BMD in patients with AS who have been shown to be at increased risk for fractures above the population normal. Since low BMD occurs early in disease, we screen during the first year of diagnosis with dual energy x-ray absorptiometry (DXA). If patients are found to have osteoporosis by T-score of less than -2.5 or if their Z-score on DXA is more than two standard deviations below the mean, we initiate therapy with bisphosphonates in males and in females who are not planning any future pregnancies. While reduction in fracture risk with bisphosphonate therapy has not been clearly defined in patients with AS, reduction in vertebral and hip fractures has been well established in primary osteoporosis and thus it is our first line treatment. If there are contraindications to the use of bisphosphonates in the treatment of low BMD, we will consider the use of denosumab. If the patient is not receiving a TNF-alpha inhibitor (TNFi) and has active disease, we also favor early initiation of TNFi due to their positive effects on BMD though the outcome on reduction in vertebral fractures remains unclear. We counsel all patients regarding the importance of adequate intake of vitamin D and calcium per the Institute of Medicine guidelines. All patients should be encouraged to participate in weight-bearing activities with a focus on core strength and gait training.
低骨密度（BMD）日益被认为是强直性脊柱炎（AS）的一种常见合并症。由于低骨密度会增加骨折风险，因此对于已被证明骨折风险高于人群正常水平的AS患者，识别和治疗低骨密度非常重要。由于低骨密度在疾病早期就会出现，我们在诊断的第一年使用双能X线吸收法（DXA）进行筛查。如果患者通过T值小于-2.5被发现患有骨质疏松症，或者其DXA的Z值比平均值低两个标准差以上，对于不打算未来怀孕的男性和女性，我们开始使用双膦酸盐进行治疗。虽然双膦酸盐治疗对AS患者骨折风险的降低尚未明确界定，但在原发性骨质疏松症中，椎体和髋部骨折的减少已得到充分证实，因此它是我们的一线治疗方法。如果在治疗低骨密度时使用双膦酸盐存在禁忌证，我们将考虑使用地诺单抗。如果患者未接受肿瘤坏死因子-α抑制剂（TNFi）且患有活动性疾病，我们也倾向于早期开始使用TNFi，因为它们对骨密度有积极影响，尽管椎体骨折减少的结果仍不明确。我们根据医学研究所的指南，向所有患者咨询充足摄入维生素D和钙的重要性。应鼓励所有患者参加负重活动，重点是核心力量和步态训练。
