Impact of Pneumococcal Urinary Antigen Testing in COVID-19 Patients: Outcomes from the San Matteo COVID-19 Registry (SMACORE).

Pietro Valsecchi,Marta Colaneri,Rita Minucci,Raffaele Bruno,Filippo Costanzo,Tiberio Oggionni,Silvia Roda,Elia Fraolini,Erika Asperges,Valentina Zuccaro,Claudio Tirelli,Bianca Mariani,Matteo Bosio,Francesco Bertuccio,Angelo Corsico

doi:10.3390/jpm11080762

Abstract

Despite low rates of bacterial co-infections, most COVID-19 patients receive antibiotic therapy. We hypothesized that patients with positive pneumococcal urinary antigens (PUAs) would benefit from antibiotic therapy in terms of clinical outcomes (death, ICU admission, and length of stay). The San Matteo COVID-19 Registry (SMACORE) prospectively enrolls patients admitted for COVID-19 pneumonia at IRCCS Policlinico San Matteo, Pavia. We retrospectively extracted the data of patients tested for PUA from October to December 2020. Demographic, clinical, and laboratory data were recorded. Of 469 patients, 42 tested positive for PUA (8.95%), while 427 (91.05%) tested negative. A positive PUA result had no significant impact on death (HR 0.53 CI [0.22–1.28] p-value 0.16) or ICU admission (HR 0.8; CI [0.25–2.54] p-value 0.70) in the Cox regression model, nor on length of stay in linear regression (estimate 1.71; SE 2.37; p-value 0.47). After adjusting for age, we found no significant correlation between urinary antigen positivity and variations in the WHO ordinal scale and laboratory markers at admission and after 14 days. We found that a positive PUA result was not frequent and had no impact on clinical outcomes or clinical improvement. Our results did not support the routine use of PUA tests to select COVID-19 patients who will benefit from antibiotic therapy.

Highlights

Bacterial co-infection is frequently described in patients affected by viral respiratory infections and is characterized by increased morbidity and mortality
Results of the Cox proportional-hazard regressions are reported as Hazard Ratios (HR) with 95% Confidence Intervals (CI); results of the linear regression and the linear mixed models are reported as unstandardized betas
We did not observe any impact of a positive pneumococcal urinary antigens (PUAs) result on clinical improvement or clinical outcomes in terms of mortality, intensive care units (ICU) admission, and length of stay

Summary

Introduction

Bacterial co-infection is frequently described in patients affected by viral respiratory infections and is characterized by increased morbidity and mortality. During the 2009 H1A1 influenza pandemic, bacterial co-infection was reported in 12% of hospitalized patients, with the proportion growing to 30% in those admitted to intensive care units (ICU). The frequency of bacterial co-infections in COVID-19 patients varies widely in different studies but seems to be low globally. A systematic review and meta-analysis reported an overall prevalence of bacterial infections of 7.1% [3,4,5,6,7]. The prevalence of bacterial co-infections upon presentation was lower than the rate of secondary infections occurring more than 48 h after hospital admission (3.5% versus 15.5%)

Methods

Results

Conclusion