The incidence of mucocutaneous lymph node syndrome (MCLS), also known as Kawasaki disease (KD), has been increasing year by year. Coronary artery lesions (CAL) induced by KD has become the main cause of acquired heart disease in children. Many clinical studies show that mycoplasma pneumoniae (MP) is associated with CAL in KD, but the strength of association between them differs across original research on different individuals.

To systematically evaluate the correlation between MP infection and CAL in KD, providing evidence for early and timely delivery of effective clinical treatment to improve the quality of life and to prevent adverse outcomes in children with KD.

Observational studies on KD〔KD patients with MP infection (MP-IgM positive) (exposed group) compared with those with simple KD (control group), with CAL as the outcome measure〕 were retrieved from databases of CNKI, Wanfang Data, VIP, SinoMed, PubMed, Embase, Cochrane Library and Web of Science from inception to April 3, 2022. Two researchers independently performed literature screening and data exaction. The Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of included studies. Stata 15.0 and RevMan 5.4 were used for data analysis.

A total of 31 studies involving 6 131 subjects were included. The average quality score of the studies rated using the NOS was 7, indicating a high overall quality. Meta-analysis showed that the risk of CAL in the exposed group was higher than that in the control group〔RR=1.65, 95%CI (1.40, 1.94), P<0.000 01〕. Subgroup analysis based on baseline data revealed that, the risk of CAL in exposed group was higher in studies on exposed and control groups with matched baseline data〔RR=1.92, 95%CI (1.71, 2.16), P<0.000 01〕, but was similar in studies on two groups with unmatched baseline data〔RR=0.98, 95%CI (0.91, 1.06), P=0.65〕. Furthermore, the risk of CAL was found to be higher in the exposed group in subgroup analysis based on MP infection diagnosed serologically with IgM>1∶160, or by quantitative PCR, or undescribed method (P<0.05). And in subgroup analysis based on age, C-creactive protein/procalcitonin ratio, or undescribed method, the risk of CAL was still higher in the exposed group (P<0.05). Egger's and Begg's tests showed that all the studies had publication bias (P<0.05). However, the comparison of the pooled effect size using the random effects model〔RR=1.32, 95%CI (1.13, 1.54), P<0.000 01〕 showed that the results before and after trimming and filling were not reversed, indicating that the results of this study were relatively stable.

MP infection increased the risk of CAL in children with KD. Early detection of MP and timely delivery of effective intervention are very important.

小儿皮肤黏膜淋巴结综合征（MCLS）即川崎病（KD），发病率逐年上升，KD所致的冠状动脉损伤（CAL）已成为儿童获得性心脏病的主要原因，多项临床研究表明肺炎支原体（MP）感染与KD发生CAL相关，但不同个体的原始研究结果存在差异。

系统评估MP感染与KD发生CAL的相关性，为临床治疗提供循证依据，以便进行早期、及时、有效的干预，提高KD患儿的生存质量，避免不良后果的发生。

计算机检索中国知网（CNKI）、万方数据知识服务平台、维普网（VIP）、中国生物医学文献服务系统（SinoMed）、PubMed、Embase、Cochrane Library、Web of Science中有关KD的观察性研究，暴露组为KD合并MP感染（MP-IgM阳性），对照组为单纯KD，结局指标为发生CAL。检索时限为建库至2022-04-03。由2名研究者独立对文献进行筛选并提取信息，采用纽卡斯尔-渥太华质量评估量表（NOS）对纳入文献的质量进行评估。使用Stata 15.0软件、RevMan 5.4软件进行数据分析。

本研究共纳入31篇文献，包含6 131例研究对象。NOS质量评价平均得分为7分，总体质量较高。Meta分析结果显示，暴露组发生CAL的风险高于对照组〔RR=1.65，95%CI（1.40，1.94），P<0.000 01〕。根据组间基线是否统一进行亚组分析，组间基线统一的文献的Meta分析结果显示，暴露组发生CAL的风险高于对照组〔RR=1.92，95%CI（1.71，2.16），P<0.000 01〕。组间基线不统一的文献的Meta分析结果显示，两组CAL发生风险比较，差异无统计学意义〔RR=0.98，95%CI（0.91，1.06），P=0.65〕。分别以IgM>1∶160、IgM定性、未描述作为MP诊断标准的亚组Meta分析结果显示，暴露组发生CAL的风险均高于对照组（P<0.05）；分别以依据年龄、根据比值、未描述作为CAL诊断标准的亚组Meta分析结果显示，暴露组发生CAL的风险均高于对照组（P<0.05）。Egger's和Begg's检验发表偏倚提示31篇文献存在发表偏倚（P<0.05）。但剪补后采用随机效应模型合并效应量〔RR=1.32，95%CI（1.13，1.54），P<0.000 01〕与剪补前采用随机效应模型合并效应量对比发现，剪补前后结果未发生逆转，说明本研究结果相对稳定。

MP感染增加了KD患儿发生CAL的风险。早期检测MP，并在早期进行有效的干预是十分重要的。