血清炎症指标及关节液分析在类风湿关节炎假体周围感染诊断中的应用

Serum inflammation index and synovial fluid analysis in the diagnosis of periprosthetic joint infection in patients with rheumatoid arthritis

目的探讨血清C-反应蛋白(C-reactive protein,CRP)、红细胞沉降率(erythrocyte sedimentation rate,ESR)、关节液白细胞计数(white blood-cell count,WBC)及多形核细胞(polymorphonuclear cells,PMN)比例诊断类风湿关节炎(rheumatoid arthritis,RA)患者假体周围感染(periprosthetic joint infection,PJI)的阈值。方法回顾性分析2006年1月至2019年12月收治的既往接受人工膝、髋关节置换术的246例RA和骨关节炎(osteoarthritis,OA)患者的临床资料。将患者按病种和是否发生PJI进行分组:RA-PJI组46例,RA-非PJI组64例,OA-PJI组72例,OA-非PJI组64例。采用受试者工作特征(receiver operating characteristics,ROC)曲线确定CRP、ESR、关节液WBC及PMN比例诊断RA-PJI和OA-PJI的最佳截断值,通过比较各项指标的曲线下面积(area under curve,AUC)及应用联合试验分析结果评价血清及关节液指标的最佳截断值对RA-PJI的诊断效能。结果在预测PJI时,RA-PJI组和OA-PJI组的血清学及关节液指标的检测结果不同。ROC曲线分析结果显示各检测指标的最佳截断值为:诊断RA-PJI的CRP最佳截断值为14.4 mg/L,ESR为39 mm/1 h,关节液WBC为3654×106/L,PMN比例为0.659;诊断OA-PJI分别为8.16 mg/L、31 mm/1 h、2452×106/L、0.625。在RA-PJI组中各检测指标的AUC与AUC=0.5的差异均有统计学意义(P<0.05)。其中关节液WBC的特异性为92.3%、AUC为0.879(95%CI:0.776,0.982)、阳性预测值为87.8%、阳性似然比为10.21,均较CRP、ESR、PMN比例高。联合试验分析诊断RA-PJI的结果为:串联试验的特异性为100%,并联试验敏感性为100%;联合指标诊断试验的特异性为100%、AUC为0.926(95%CI:0.848,1.000),AUC与AUC=0.5的差异有统计学意义(P<0.05)。结论CRP、ESR、关节液WBC及PMN比例在诊断RA患者PJI时的最佳截断值均高于OA患者,其最佳截断值可作为明确RA患者PJI诊断的重要辅助指标;其中关节液WBC与其他指标相比预测能力强、误诊率低,是鉴别RA患者PJI与否的最佳检测指标;联合试验可提高RA患者PJI诊断的敏感性或特异性,联合多项检测指标可为早期准确诊断RA患者PJI提供参考依据。

Objective To investigate the threshold of serum C-reactive protein(CRP),erythrocyte sedimentation rate(ESR),synovial fluid white blood-cell count(WBC)and polymorphonuclear cells(PMN)proportion in the diagnosis of periprosthetic joint infection(PJI)in patients with rheumatoid arthritis(RA).Methods The clinical data of 246 patients with RA and osteoarthritis(OA)who had previously undergone total knee and hip arthroplasty from January 2006 to December 2019 was retrospectively analyzed.The patients were divided into four groups according to the disease type and whether PJI occurred,namely 46 patients in the RA-PJI group,64 patients in the RA-non-PJI group,72 patients in the OA-PJI group,and 64 patients in the OA-non-PJI group.The receiver operating characteristics(ROC)curve was used to determine the optimum cut-off values of CRP,ESR,synovial fluid WBC and PMN proportion for diagnosing the RA-PJI and OA-PJI.The optimal cut-off values of serum and synovial fluid indexes were evaluated for the diagnostic efficacy of RA-PJI by comparing the area under curve(AUC)of each index.Further,the values were applied for joint test analysis.Results For PJI prediction,the results of serological and synovial fluid indexes were different between RA-PJI group and OA-PJI group.The results of ROC curve analysis showed that the optimal cut-off values of each detection index were as follows.The optimal cut-off value of CRP for diagnosing RA-PJI was 14.4 mg/L,ESR was 39 mm/1 h,synovial fluid WBC was 3654×106/L,and PMN proportion was 0.659.The optimal cut-off value for diagnosing OA-PJI were 8.16 mg/L,31 mm/1 h,2452×106/L,and 0.625,respectively.In the RA-PJI group,the difference between the AUC of each detection index and AUC=0.5 was statistically significant(P<0.05).Among them,the specificity of synovial fluid WBC was 92.3%,AUC was 0.879(95%CI:0.776,0.982)with 87.8%positive predictive value and 10.21 positive likelihood ratio.These values were higher than those of CRP,ESR,and PMN proportion.The results of joint test analysis for the diagnosis of RA-PJI were as follows.The specificity of the series test was 100%,and the sensitivity of the parallel test was 100%;the specificity of the joint index diagnostic test was 100%,AUC was 0.926(95%CI:0.848,1.000),the difference between AUC and AUC=0.5 was statistically significant(P<0.05).Conclusion The optimum cut-off values of CRP,ESR,synovial fluid WBC and PMN proportion for the diagnosis of PJI in patients with RA are all higher than those of patients with OA.Their optimal cut-off values can be used as important auxiliary indexes for a clear diagnosis of PJI in patients with RA.Compared with other indexes,the synovial fluid WBC has strong predicting power and lower misdiagnosis rate,which could be the best detection index for identifying PJI in patients with RA.The joint test could improve the sensitivity or specificity of PJI diagnosis in patients with RA.The combination with multiple detection indexes could provide a reference for the early and accurate diagnosis of PJI in patients with RA.