肾功能受损对细菌性血流感染患者降钙素原的影响

Effect of renal function impairment on procalcitonin in patients with bacterial bloodstream infection

目的探讨细菌性血流感染患者肾功能对血清降钙素原(PCT)水平的影响。方法回顾性收集某院2014年5月—2017年11月双份血培养结果阳性且在血培养前后12 h内行血清PCT检查的病例,按照血培养病原菌革兰染色结果和肾功能水平进行分组,分为革兰阳性(G^+)菌肾功能正常组、G^+菌肾功能受损组(含重度受损组),革兰阴性(G^-)菌肾功能正常组、G^-菌肾功能受损组(含重度受损组)。分别比较组间PCT水平,用受试者工作特征(ROC)曲线评估PCT水平对肾功能损伤合并血流感染患者感染情况的预测价值。结果G^+菌肾功能正常组23例、受损组27例(含重度受损组11例),G^-菌肾功能正常组63例、受损组74例(含重度受损组23例)。G^+菌、G^-菌肾功能正常组与肾功能受损组患者PCT水平比较,差异均无统计学意义(均P>0.05);G^-菌肾功能正常组患者PCT水平为[2.63(0.58～9.28)]ng/m L,低于G^-菌肾功能重度受损组患者的[18.23(8.55～49.72)]ng/m L(P<0.001)。依据其PCT折点将G^-菌肾功能正常组与重度受损组患者的Ccr分为两部分(PCT水平>4.26 ng/m L和PCT水平≤4.26 ng/m L)绘制ROC曲线,曲线下面积(AUC)为0.664(P=0.009)。Ccr以71.81 m L/min为临界值时,患者PCT水平受到肾功能重度损伤影响的阳性预测值灵敏度为86.0%,特异度为51.2%。结论当患者肾功能重度受损合并G^-菌血流感染时,其PCT水平较肾功能正常患者判断脓毒血症的阈值(>0.5 ng/m L)需进一步提高。

Objective To evaluate the effect of renal function on serum procalcitonin in patients with bacterial bloodstream infection (BSI).Methods Patients with double positive blood culture from May 2014 to November 2017 and detected serum procalcitonin(PCT) 12 hours before and after blood culture were analyzed retrospectively.They were grouped according to gram-staining result of pathogens from blood culture and renal function,four groups were gram-positive bacteria with normal renal function group(G^+/NRF group),gram-positive bacteria with impaired renal function group (including severely impaired)(G^+/IRF group),gram-negative bacteria with normal renal function group(G^-/NRF group),and gram-negative bacteria with impaired renal function group (including severely impaired)(G^-/IRF group).Levels of PCT among groups were compared,value of PCT level in predicting infection condition of patients with renal impairment and BSI was evaluated by receiver operating characteristic (ROC) curve.Results There were 23 cases in G^+/NRF group,27 in G^+/IRF group (including 11 severely impaired cases),63 in G^-/NRF group,and 74 in G^-/IRF group (including 23 severely impaired cases).PCT levels between G +/NRF group and G^+/IRF group,as well as G^-/NRF group and G^-/IRF group were neither significantly different (both P >0.05);PCT level in G -/NRF group was lower than that in severe G^-/IRF group (2.63 [0.58-9.28]ng/mL VS 18.23 [8.55-49.72] ng/mL,P <0.001).According to PCT break point,endogenous creatinine clearance rate (Ccr) of G^-/NRF group and severe G^-/ IRF group was divided into two parts (PCT level > 4.26 ng/mL and PCT level≤4.26 ng/mL),ROC curve was drawn,and the area under curve (AUC) was 0.664 ( P =0.009).When cutoff for Ccr was 71.81 mL/min ,the sensitivity and specificity of positive predictive value of PCT level affected by severe impairment of renal function were 86.0% and 51.2% respectively.Conclusion When patient’s renal function is severely impaired and G^- bacteria BSI occurs,the threshold value of PCT level for judging sepsis needs to be further improved than patient with normal renal function ( >0.5 ng/mL).