Medical Intensive Care Unit, Peking Union Medical College, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan, Dongcheng District, Beijing, 100730, China.
Department of Clinical Laboratory, Peking Union Medical College, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan, Dongcheng District, Beijing, 100730, China.
BMC Infect Dis. 2024 Sep 20;24(1):1015. doi: 10.1186/s12879-024-09873-1.
Serum (1,3)-β-D-glucan (BDG) detection for diagnosis of Pneumocystis jirovecii pneumonia (PJP) in non-human immunodeficiency virus (HIV) immunocompromised patients lacks intensive care unit (ICU)-specific data. We aimed to assess its performance and determine the optimal cutoff for PJP in ICU population.
This retrospective study included critically ill non-HIV immunocompromised patients admitted to a medical ICU with suspected pneumonia, undergoing simultaneous microbiological testing for P. jirovecii on lower respiratory tract specimens and serum BDG. Confounders affecting BDG positivity were explored by multivariable logistic regression. Optimal cut-offs were derived from Youden's index for the entire cohort and subgroups stratified by confounders. Diagnostic performance of serum BDG was estimated at different cutoffs.
Of 400 patients included, 42% were diagnosed with PJP and 58.3% had positive serum BDG. Serum BDG's area under the receiver operating characteristic curve was 0.90 (0.87-0.93). At manufacturer's 150 pg/ml cut-off, serum BDG had high sensitivity and negative predictive value (94%), but low specificity and positive predictive value (67%). Confounders associated with a positive serum BDG in PJP diagnosis included IVIG infusion within 3 days (odds ratio [OR] 9.24; 95% confidence interval [CI] 4.09-20.88, p < 0.001), other invasive fungal infections (OR 4.46; 95% CI 2.10-9.49, p < 0.001) and gram-negative bacteremia (OR 29.02; 95% CI 9.03-93.23, p < 0.001). The application of optimal BDG cut-off values determined by Youden's index (252 pg/ml, 390 pg/ml, and 202 pg/ml) specific for all patients and subgroups with or without confounders improved the specificity (79%, 74%, and 88%) and corresponding PPV (75%, 65%, and 85%), while maintaining reasonable sensitivity and NPV.
Tailoring serum BDG cutoff specific to PJP and incorporating consideration of confounders could enhance serum BDG's diagnostic performance in the ICU settings.
血清（1,3）-β-D-葡聚糖（BDG）检测用于诊断非人类免疫缺陷病毒（HIV）免疫抑制患者的卡氏肺孢子菌肺炎（PJP）缺乏重症监护病房（ICU）特异性数据。我们旨在评估其性能并确定 ICU 人群中 PJP 的最佳截断值。
本回顾性研究纳入了因疑似肺炎入住内科 ICU 的非 HIV 免疫抑制重症患者，同时对下呼吸道标本和血清 BDG 进行卡氏肺孢子菌的微生物学检测。通过多变量逻辑回归探讨影响 BDG 阳性的混杂因素。根据 Youden 指数为整个队列和按混杂因素分层的亚组得出最佳截断值。在不同截断值下评估血清 BDG 的诊断性能。
400 例患者中，42%诊断为 PJP，58.3%血清 BDG 阳性。血清 BDG 的受试者工作特征曲线下面积为 0.90（0.87-0.93）。在制造商规定的 150 pg/ml 截断值下，血清 BDG 具有高灵敏度和阴性预测值（94%），但特异性和阳性预测值（67%）较低。与 PJP 诊断中血清 BDG 阳性相关的混杂因素包括 3 天内静脉注射免疫球蛋白（IVIG）输注（比值比[OR] 9.24；95%置信区间[CI] 4.09-20.88，p<0.001）、其他侵袭性真菌感染（OR 4.46；95%CI 2.10-9.49，p<0.001）和革兰氏阴性菌血症（OR 29.02；95%CI 9.03-93.23，p<0.001）。应用 Youden 指数确定的针对所有患者和有无混杂因素的亚组的最佳 BDG 截断值（252 pg/ml、390 pg/ml 和 202 pg/ml）特异性提高了特异性（79%、74%和 88%）和相应的阳性预测值（75%、65%和 85%），同时保持了合理的敏感性和阴性预测值。
针对 PJP 定制血清 BDG 截断值并考虑混杂因素可以提高 ICU 环境中血清 BDG 的诊断性能。
