Department of Rheumatology and Clinical Immunology, Chinese Academy of Medical Sciences & Peking Union Medical College; National Clinical Research Center for Dermatologic and Immunologic Diseases (NCRC-DID), Ministry of Science & Technology; State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital (PUMCH); Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing, 100730, China.
Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, 100730, China.
Arthritis Res Ther. 2021 Apr 24;23(1):127. doi: 10.1186/s13075-021-02503-0.
Patients with rheumatoid arthritis (RA) are at increased risk of fractures. Although their decline in bone mineral density (BMD) is well-established, data regarding the alterations in bone microarchitecture are limited. In this study, we aimed to evaluate bone microarchitecture, geometry, and volumetric BMD among patients with RA in mainland China using high-resolution peripheral quantitative computed tomography (HRpQCT).
In this cross-sectional study, patients with RA were recruited from the Peking Union Medical College Hospital site of the Chinese Registry of rhEumatoiD arthrITis (CREDIT). Each participant underwent HRpQCT scanning (Scanco XtremeCT II), thoracolumbar X-ray and dual-energy X-ray absorptiometry. The primary outcomes were HRpQCT-related measures at distal radius and tibia. Data regarding demographic features, RA-related characteristics, and history of fragility fractures were collected. Correlation between HRpQCT parameters and potentially related factors were analyzed using linear regression analysis. A group of age- and sex-matched healthy controls was included for comparison.
A total of 81 patients with RA [69 women, aged 57.9 ± 8.7 years, disease duration 5.7 (IQR 1.4-11.2) years] and 81 matched healthy controls were included. Compared with controls, patients with RA had significantly larger bone area and lower total and trabecular vBMD at both the distal radius and tibia. Lower cortical bone thickness was also shown at the distal tibia. Among patients with RA, advanced age, low BMI, female sex, disease duration, and activity were associated with decreased vBMD and impaired bone microstructure. Female reproductive factors including menopause, late menarche, breast feeding, and early childbirth also showed negative correlation with these parameters. Compared to patients with RA without fractures, patients with fragility fractures (n = 11) showed lower trabecular and cortical vBMD, thinner cortical bone, impaired trabecular microstructure, and a trend of declined bone strength. Current glucocorticoid intake was related to decreased vBMD, trabecular number, increased trabecular separation, and inhomogeneity.
In this study, we observed alterations in bone mineral density, geometry, and microarchitecture among patients with RA compared to healthy individuals, which may impair bone strength and lead to increased risk of fractures. Both traditional risk factors for osteoporosis and RA-associated factors need to be considered in the assessment of the bone quality.
类风湿关节炎（RA）患者骨折风险增加。尽管其骨密度（BMD）下降已得到充分证实，但有关骨微结构变化的数据有限。本研究旨在使用高分辨率外周定量计算机断层扫描（HRpQCT）评估中国大陆 RA 患者的骨微结构、几何形状和容积 BMD。
这是一项横断面研究，RA 患者来自中国类风湿关节炎注册研究（CREDIT）北京协和医院的研究点。每位参与者均接受 HRpQCT 扫描（Scanco XtremeCT II）、胸腰椎 X 射线和双能 X 射线吸收法检查。主要结局为桡骨远端和胫骨的 HRpQCT 相关测量值。收集人口统计学特征、RA 相关特征和脆性骨折史的数据。采用线性回归分析分析 HRpQCT 参数与潜在相关因素之间的相关性。纳入一组年龄和性别匹配的健康对照者进行比较。
共纳入 81 例 RA 患者[69 例女性，年龄 57.9±8.7 岁，病程 5.7（IQR 1.4-11.2）年]和 81 例匹配的健康对照者。与对照组相比，RA 患者的桡骨远端和胫骨的骨面积更大，总骨密度和小梁骨密度更低。胫骨远端的皮质骨厚度也较低。在 RA 患者中，年龄较大、BMI 较低、女性、病程和活动度与骨密度降低和骨微结构受损有关。女性生殖因素，如绝经、初潮晚、母乳喂养和早育，也与这些参数呈负相关。与无脆性骨折的 RA 患者（n=11）相比，脆性骨折患者的小梁和皮质骨密度较低、皮质骨较薄、小梁微结构受损且骨强度呈下降趋势。目前糖皮质激素的摄入与骨密度、小梁数量、小梁分离增加和不均匀性降低有关。
与健康人相比，本研究观察到 RA 患者的骨密度、几何形状和微结构发生改变，这可能会损害骨强度并导致骨折风险增加。在评估骨质量时，需要考虑骨质疏松症的传统危险因素和 RA 相关因素。
