Department of General Practice, Erasmus Medical Center, PO Box 2040, Rotterdam 3000CA, The Netherlands.
Ann Rheum Dis. 2012 Sep;71(9):1517-23. doi: 10.1136/annrheumdis-2011-200687. Epub 2012 Apr 4.
Although pain due to osteoarthritis (OA) generally deteriorates over time, there is a large individual variation in the course of pain. This study examines the different longitudinal trajectories of patients with hip pain due to OA.
Data from a previously performed randomised controlled trial were used to investigate the course of pain over 2 years in 222 patients with clinically and radiographically determined hip OA. Pain was measured with a visual analogue scale (0-100). Latent class growth analysis was used to determine the number of trajectories of patients with hip pain due to OA.
Analyses yielded five trajectories of pain due to hip OA. Trajectory 1 ('mild pain'; n=69) consists of patients with stable mild pain. Patients in trajectory 2 ('moderate pain'; n=31) fluctuated slightly between moderate and severe pain levels. Trajectory 3 ('always pain'; n=32) consists of patients with severe pain. Patients in trajectory 4 ('regularly progressing'; n=48) started with mild pain and progressed slowly to moderate pain. Trajectory 5 ('highly progressing'; n=42) patients also started with mild pain but quickly progressed to severe pain over 2 years. Compared with the 'mild pain' group, patients in the 'always pain' group had more severe radiographic hip OA, morning stiffness and decreased range of motion. The 'highly progressing' group had more severe radiographic hip OA and morning stiffness.
Latent class growth analysis applied to longitudinal data of patients with hip OA identified five distinct trajectories of pain. More studies are needed to externally validate these findings.
尽管骨关节炎（OA）引起的疼痛通常会随时间恶化，但疼痛的进程在个体间存在很大差异。本研究旨在探讨髋部 OA 患者疼痛的不同纵向轨迹。
本研究使用先前进行的随机对照试验的数据，对 222 例临床和影像学诊断为髋部 OA 的患者进行了为期 2 年的疼痛进程研究。疼痛采用视觉模拟评分（0-100）进行测量。采用潜在类别增长分析确定髋部 OA 患者疼痛的轨迹数量。
分析得到了髋部 OA 疼痛的五种轨迹。轨迹 1（“轻度疼痛”；n=69）为疼痛稳定的轻度疼痛患者。轨迹 2（“中度疼痛”；n=31）为疼痛在中度和重度之间波动的患者。轨迹 3（“持续疼痛”；n=32）为重度疼痛患者。轨迹 4（“定期进展”；n=48）为轻度疼痛患者，疼痛缓慢进展为中度疼痛。轨迹 5（“快速进展”；n=42）患者也从轻度疼痛开始，但在 2 年内迅速进展为重度疼痛。与“轻度疼痛”组相比，“持续疼痛”组的髋关节 OA 影像学表现更严重，晨僵和活动范围受限更明显。“快速进展”组的髋关节 OA 影像学表现和晨僵更严重。
潜在类别增长分析应用于髋部 OA 患者的纵向数据，确定了疼痛的五种不同轨迹。需要进一步的研究来验证这些发现。
