Section of Endocrinology, Department of Medical Sciences, University of Ferrara, Via Savonarola 9, 44121 Ferrara, Italy.
Bone. 2013 Oct;56(2):426-31. doi: 10.1016/j.bone.2013.07.010. Epub 2013 Jul 17.
Bisphosphonates (BPs) are the first-line therapy for osteoporosis. In recent years, atypical femoral fractures (AFF) have been described in patients on BPs therapy. However, the relationship between BPs and AFF remains to be clarified. We evaluated clinical and hormonal characteristics of AFF patients, in order to determine AFF risk factors. We studied 11 females with AFF and 58 females with typical femoral fractures (TFF), admitted to our Department for surgical repair between January 2008 and December 2011. All AFF patients received BPs therapy for 6 to 13 yrs, whereas 36.2% (p<0.0001) of TFF patients received BPs for shorter period (TFF, 6.1±1.8 yr vs. AFF, 8.6±1.9 yr, p<0.0001). A higher prevalence of hypocalcemia was observed in AFF patients compared with TFF (p<0.02), with significantly (p<0.05) lower corrected calcium levels in AFF patients. By contrast a reduced prevalence of elevated PTH levels (p<0.05) was found in AFF patients. No significant difference in prevalence of vitamin D defect was observed between the two groups. Younger age (p<0.004), higher BMI (>30 kg/m2, p<0.03) and early menopausal age (p<0.05) were observed in AFF patients. At time of fracture, prevalence of osteopenia/osteoporosis and levels of bone turnover markers were significantly (p<0.01) lower in AFF compared with TFF patients. By multivariate analysis hypocalcemia, obesity, and younger age (<70 yr) were confirmed to be independent predictors of AFF; elevated PTH level was the predominant independent protective factor (p<0.004). In conclusion, our data indicate that clinical characteristics and metabolic factors may favor the development of AFF in BP treated patients. We identified hypocalcemia due to latent hypoparathyroidism as primary risk factor for AFF; age, obesity, early menopause, and BMD may also influence the development of AFF. An adequate clinical and metabolic assessment is suggested to prevent the development of AFF in BP treated patients.
双膦酸盐（BPs）是骨质疏松症的一线治疗药物。近年来，在接受 BPs 治疗的患者中出现了非典型股骨骨折（AFF）。然而，BPs 和 AFF 之间的关系仍需澄清。我们评估了 AFF 患者的临床和激素特征，以确定 AFF 的危险因素。我们研究了 2008 年 1 月至 2011 年 12 月在我们科接受手术修复的 11 名 AFF 女性患者和 58 名 TFF 女性患者。所有 AFF 患者均接受 BPs 治疗 6 至 13 年，而 36.2%（p<0.0001）的 TFF 患者接受 BPs 治疗时间较短（TFF，6.1±1.8 年 vs. AFF，8.6±1.9 年，p<0.0001）。与 TFF 患者相比，AFF 患者更易出现低钙血症（p<0.02），且 AFF 患者校正钙水平显著降低（p<0.05）。相反，AFF 患者甲状旁腺激素升高的患病率较低（p<0.05）。两组维生素 D 缺陷的患病率无显著差异。AFF 患者年龄较小（p<0.004），BMI 较高（>30 kg/m2，p<0.03），绝经年龄较早（p<0.05）。骨折时，AFF 患者的骨质疏松/骨量减少患病率和骨转换标志物水平明显较低（p<0.01）。通过多变量分析，低钙血症、肥胖和年龄较小（<70 岁）被确认为 AFF 的独立预测因素；甲状旁腺激素升高是主要的独立保护因素（p<0.004）。总之，我们的数据表明，临床特征和代谢因素可能有利于 BPs 治疗患者 AFF 的发生。我们确定低钙血症是由于潜在的甲状旁腺功能减退症是 AFF 的主要危险因素；年龄、肥胖、早绝经和 BMD 也可能影响 AFF 的发生。建议对接受 BPs 治疗的患者进行充分的临床和代谢评估，以预防 AFF 的发生。
