Current Pyuria Cutoffs Promote Inappropriate Urinary Tract Infection Diagnosis in Older Women

Manu P Bilsen; Margaretha J Aantjes; Esther van Andel; Janneke E Stalenhoef; Cees van Nieuwkoop; Eliane M S Leyten; Nathalie M Delfos; Martijn Sijbom; Mattijs E Numans; Wilco P Achterberg; Simon P Mooijaart; Martha T van der Beek; Christa M Cobbaert; Simon P Conroy; Leo G Visser; Merel M C Lambregts

doi:10.1093/cid/ciad099

Current Pyuria Cutoffs Promote Inappropriate Urinary Tract Infection Diagnosis in Older Women

Clin Infect Dis. 2023 Jun 16;76(12):2070-2076. doi: 10.1093/cid/ciad099.

Authors

Manu P Bilsen¹, Margaretha J Aantjes¹, Esther van Andel², Janneke E Stalenhoef³, Cees van Nieuwkoop^{4

5}, Eliane M S Leyten⁶, Nathalie M Delfos⁷, Martijn Sijbom⁵, Mattijs E Numans⁵, Wilco P Achterberg⁵, Simon P Mooijaart⁸, Martha T van der Beek⁹, Christa M Cobbaert², Simon P Conroy¹⁰, Leo G Visser¹, Merel M C Lambregts¹

Affiliations

¹ Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands.
² Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, The Netherlands.
³ Department of Internal Medicine, OVLG, Amsterdam, The Netherlands.
⁴ Department of Internal Medicine, Haga Teaching Hospital, The Hague, The Netherlands.
⁵ Department of Public Health and Primary Care, Leiden University Medical Center, The Hague, The Netherlands.
⁶ Department of Internal Medicine, Haaglanden Medisch Centrum, The Hague, The Netherlands.
⁷ Department of Internal Medicine, Alrijne Hospital, Leiderdorp, The Netherlands.
⁸ Department of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, The Netherlands.
⁹ Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands.
¹⁰ Medical Research Council Unit for Lifelong Health and Ageing at University College London, University College London, London, United Kingdom.

Abstract

Background: 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.

Methods: 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.

Results: 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%.

Conclusions: 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).

Keywords: asymptomatic bacteriuria; microscopy; pyuria; urinary tract infection; urine flowcytometry.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aged
Bacteriuria* / drug therapy
Female
Humans
Pyuria* / diagnosis
Pyuria* / epidemiology
Pyuria* / etiology
ROC Curve
Sensitivity and Specificity
Urinary Tract Infections* / drug therapy

Associated data

NTR/NL9477