Modic changes—Their associations with low back pain and activity limitation: A systematic literature review and meta-analysis

Background
Previous systematic reviews have reported positive associations between Modic changes (MCs) and low back pain (LBP), but due to their narrow scope and new primary studies, there is a need for a comprehensive systematic review. Our objectives were to investigate if MCs are associated with non-specific LBP and/or activity limitation and if such associations are modified by other factors.
Methods
A protocol for this review was registered at PROSPERO prior to commencing the work (PROSPERO record: CRD42015017350). The MEDLINE, CINAHL and EMBASE databases were searched for relevant studies from first record to June 15th 2016. Prospective or retrospective cross-sectional cohort studies and case-control studies including people of all ages from general, working and clinical study populations were eligible for inclusion. Risk of bias assessment and data extraction for associations and potential modifiers were completed independently by pairs of reviewers. Meta-analysis was performed for homogeneous studies and presented as odds ratios (OR) with 95% CI.
Results
In all, 5210 citations were identified and 31 studies were included. One study had low risk of bias. Fifteen studies (48%) reported statistically significant positive associations between MCs and LBP and one study found a statistically significant negative association. Meta-analysis performed for studies using concordant pain with provocative discography as the clinical outcome resulted in an OR of 4.01 (1.52–10.61). One of seven studies reported a statistically significant positive association between MCs and activity limitation. Lumbar disc level and disc degeneration were found to modify the association between MCs and LBP.
Conclusions
The results from this comprehensive systematic review indicate that the associations between MCs and LBP-related outcomes are inconsistent. The high risk of bias and the heterogeneity in terms of study samples, clinical outcomes and prevalence estimates of MCs and LBP may explain these findings. It is likely that new studies with low risk of bias will affect the direction and strength of these associations.

背景
既往系统综述已报道莫迪克改变（Modic changes, MCs）与腰背痛（low back pain, LBP）存在正向关联，但由于既往综述覆盖范围较窄且新的原始研究不断涌现，亟需开展一项全面的系统综述。本研究旨在探究莫迪克改变是否与非特异性腰背痛及/或活动受限相关，以及此类关联是否受其他因素调节。
方法
本项综述的研究方案已于工作开展前在PROSPERO平台注册（PROSPERO记录编号：CRD42015017350）。检索MEDLINE、CINAHL及EMBASE数据库，检索时限为从各数据库首条记录至2016年6月15日。纳入涵盖普通人群、职业人群及临床研究人群所有年龄段受试者的前瞻性或回顾性横断面队列研究、病例对照研究。由两名评审员组成的独立小组完成偏倚风险评估、关联数据及潜在调节因素的数据提取工作。对同质研究进行Meta分析，结果以比值比（odds ratio, OR）与95%置信区间（95% CI）呈现。
结果
共检索到5210条引文，最终纳入31项研究。其中1项研究偏倚风险较低。15项研究（占比48%）报道莫迪克改变与腰背痛间存在具有统计学意义的正向关联，另有1项研究发现二者间存在具有统计学意义的负向关联。针对以一致性疼痛伴激发性椎间盘造影作为临床结局的研究开展的Meta分析显示，其比值比为4.01（95%CI：1.52~10.61）。7项相关研究中仅1项报道莫迪克改变与活动受限间存在具有统计学意义的正向关联。研究发现，腰椎间盘节段及椎间盘退变程度可调节莫迪克改变与腰背痛间的关联。
结论
本项全面系统综述的结果表明，莫迪克改变与腰背痛相关结局间的关联并不一致。研究样本、临床结局、莫迪克改变及腰背痛患病率估算方面存在的高偏倚风险与异质性，或可解释上述研究结果。未来开展的低偏倚风险新研究，可能会改变此类关联的方向与强度。