Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands.
Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, The Netherlands.
Clin Infect Dis. 2023 Jun 16;76(12):2070-2076. doi: 10.1093/cid/ciad099.
Pre-existing lower urinary tract symptoms (LUTS), cognitive impairment, and the high prevalence of asymptomatic bacteriuria (ASB) complicate the diagnosis of urinary tract infection (UTI) in older women. The presence of pyuria remains the cornerstone of UTI diagnosis. However, >90% of ASB patients have pyuria, prompting unnecessary treatment. We quantified pyuria by automated microscopy and flowcytometry to determine the diagnostic accuracy for UTI and to derive pyuria thresholds for UTI in older women.
Women ≥65 years with ≥2 new-onset LUTS and 1 uropathogen ≥104 colony-forming units (CFU)/mL were included in the UTI group. Controls were asymptomatic and classified as ASB (1 uropathogen ≥105 CFU/mL), negative culture, or mixed flora. Patients with an indwelling catheter or antimicrobial pretreatment were excluded. Leukocyte medians were compared and sensitivity-specificity pairs were derived from a receiver operating characteristic curve.
We included 164 participants. UTI patients had higher median urinary leukocytes compared with control patients (microscopy: 900 vs 26 leukocytes/µL; flowcytometry: 1575 vs 23 leukocytes/µL; P < .001). Area under the curve was 0.93 for both methods. At a cutoff of 264 leukocytes/µL, sensitivity and specificity of microscopy were 88% (positive and negative likelihood ratio: 7.2 and 0.1, respectively). The commonly used cutoff of 10 leukocytes/µL had a poor specificity (36%) and a sensitivity of 100%.
The degree of pyuria can help to distinguish UTI in older women from ASB and asymptomatic controls with pyuria. Current pyuria cutoffs are too low and promote inappropriate UTI diagnosis in older women. Clinical Trials Registration. International Clinical Trials Registry Platform: NL9477 (https://trialsearch.who.int/Trial2.aspx?TrialID=NL9477).
下尿路症状（LUTS）、认知障碍和无症状性菌尿症（ASB）的高发率使老年女性尿路感染（UTI）的诊断变得复杂。脓尿的存在仍然是 UTI 诊断的基石。然而，>90%的 ASB 患者存在脓尿，这促使了不必要的治疗。我们通过自动化显微镜和流式细胞术来量化脓尿，以确定其对 UTI 的诊断准确性，并得出老年女性 UTI 的脓尿阈值。
纳入≥65 岁、≥2 种新发 LUTS 且≥1 种病原体≥104 个菌落形成单位（CFU）/mL 的患者为 UTI 组。对照组为无症状且分类为 ASB（1 种病原体≥105 CFU/mL）、阴性培养或混合菌群。排除留置导管或抗菌预处理的患者。比较白细胞中位数，并从受试者工作特征曲线中得出灵敏度-特异性对。
我们纳入了 164 名参与者。与对照组相比，UTI 患者的尿白细胞中位数更高（显微镜检查：900 与 26 个白细胞/µL；流式细胞术：1575 与 23 个白细胞/µL；P<.001）。两种方法的曲线下面积均为 0.93。在 264 个白细胞/µL 的截点处，显微镜检查的灵敏度和特异性分别为 88%（阳性和阴性似然比分别为 7.2 和 0.1）。常用的 10 个白细胞/µL 截点特异性差（36%），灵敏度为 100%。
脓尿程度有助于区分老年女性的 UTI 与 ASB 和有脓尿的无症状对照者。目前的脓尿截断值过低，导致老年女性不必要的 UTI 诊断。临床试验注册。国际临床试验注册平台：NL9477（https://trialsearch.who.int/Trial2.aspx?TrialID=NL9477）。
