Pneumococcal urinary antigen test use in diagnosis and treatment of pneumonia in seven Utah hospitals

A review of the value of point-of-care testing for community-acquired pneumonia

INTRODUCTION

Community-acquired pneumonia (CAP) is an infectious disease associated with high mortality worldwide. Although Streptococcus pneumoniae remains the most frequent pathogen in CAP, data from recent studies using molecular tests have shown that respiratory viruses play a key role in adults with pneumonia. The impact of difficult-to-treat pathogens on the outcomes of pneumonia is also important even though they represent only a small proportion of overall cases. Despite improvements in the microbiological diagnosis of CAP in recent decades, the identification of the causative pathogen is often delayed because of difficulties in obtaining good-quality sputum samples, issues in transporting samples, and slow laboratory processes. Therefore, the initial treatment of CAP is usually empirical. Point-of-care testing (POCT) was introduced to avoid treatment delays and reduce reliance on empirical antibiotics.

AREAS COVERED

This review summarizes the main scientific evidence on the role of POCT in the diagnosis and management of patients with CAP. The authors searched for articles on POCT in pneumonia on PubMed from inception to 20 January 2024. The references in the identified articles were also searched.

EXPERT OPINION

POCT involves rapid diagnostic assays that can be performed at the bedside especially in cases of severe CAP and immunocompromised patients. These tests can produce results that could help guide initial therapy and management.

Microbiology of Severe Community-Acquired Pneumonia and the Role of Rapid Molecular Techniques

The microbiology of severe community acquired pneumonia (SCAP) has implications on management, clinical outcomes and public health policy. Therefore, knowledge of the etiologies of SCAP and methods to identify these microorganisms is key. Bacteria including Streptococcus pneumoniae, Staphylococcus aureus and Enterobacteriaceae continue to be important causes of SCAP. Viruses remain the most commonly identified etiology of SCAP. Atypical organisms are also important etiologies of SCAP and are critical to identify for public health. With the increased number of immunocompromised individuals, less common pathogens may also be found as the causative agent of SCAP. Traditional diagnostic tests, including semi-quantitative respiratory cultures, blood cultures and urinary antigens continue to hold an important role in the evaluation of patients with SCAP. Many of the limitations of the aforementioned tests are addressed by rapid, molecular diagnostic tests. Molecular diagnostics utilize culture-independent technology to identify species-specific genetic sequences. These tests are often semi-automated and provide results within hours, which provides an opportunity for expedient antibiotic stewardship. The existing literature suggests molecular diagnostic techniques may improve antibiotic stewardship in CAP, and future research should investigate optimal methods for implementation of these assays into clinical practice.

Derivation and external validation of a prediction model for pneumococcal urinary antigen test positivity in patients with community-acquired pneumonia

Objective

Derive and externally validate a prediction model for pneumococcal urinary antigen test (pUAT) positivity.

Methods

Retrospective cohort study of adults admitted with community-acquired pneumonia (CAP) to 177 U.S. hospitals in the Premier Database (derivation and internal validation samples) or 12 Cleveland Clinic hospitals (external validation sample). We utilized multivariable logistic regression to predict pUAT positivity in the derivation dataset, followed by model performance evaluation in both validation datasets. Potential predictors included demographics, comorbidities, clinical findings, and markers of disease severity.

Results

Of 198,130 Premier patients admitted with CAP, 27,970 (14.1%) underwent pUAT; 1962 (7.0%) tested positive. The strongest predictors of pUAT positivity were history of pneumococcal infection in the previous year (OR 6.99, 95% CI 4.27-11.46), severe CAP on admission (OR 1.76, 95% CI 1.56-1.98), substance abuse (OR 1.57, 95% CI 1.27-1.93), smoking (OR 1.23, 95% CI 1.09-1.39), and hyponatremia (OR 1.35, 95% CI 1.17-1.55). Negative predictors included IV antibiotic use in past year (OR 0.65, 95% CI 0.52-0.82), congestive heart failure (OR 0.72, 95% CI 0.63-0.83), obesity (OR 0.71, 95% CI 0.60-0.85), and admission from skilled nursing facility (OR 0.60, 95% CI 0.45-0.78). Model c-statistics were 0.60 and 0.67 in the internal and external validation cohorts, respectively. Compared to guideline-recommended testing of severe CAP patients, our model would have detected 23% more cases with 5% fewer tests.

Conclusion

Readily available data can identify patients most likely to have a positive pUAT. Our model could be incorporated into automated clinical decision support to improve test efficiency and antimicrobial stewardship.

A case report of disseminated Streptococcus pneumoniae infection complicated by infective endocarditis, septic arthritis and epidural abscess in an immunocompetent patient

Streptococcus pneumoniae is a highly virulent, vaccine-preventable pathogen which can cause disease on a spectrum from benign to fatal. Apart from pneumonia, it commonly causes septicaemia and meningitis. This case report describes an unusual range of complications in a 53-year-old Caucasian female presenting to a regional hospital, without any risk known factors for severe disease (such as extremes of age, immunodeficiency or co-morbidities). Progressing from an episode of otitis media, her condition rapidly progressed to mastoid sinusitis, septic arthritis, infective endocarditis, epidural abscesses and multiple subcutaneous abscesses. Following quick identification of S. pneumoniae from a positive blood culture, the patient was treated with high-dose benzylpenicillin and ceftriaxone and aggressive source control by surgery, enabling a good clinical recovery.

Urinary Antigen Testing for Respiratory Infections: Current Perspectives on Utility and Limitations

Pneumonia is a leading cause of hospitalization and death due to infection worldwide. Streptococcus pneumoniae and Legionella pneumophila remain among the most commonly identified bacterial pathogens. Unfortunately, more than half of all pneumonia cases today lack an etiologic diagnosis due to limitations in traditional microbiological methods like blood and sputum cultures, which are affected by poor sample collection, prior antibiotic administration, and delayed processing. Urinary antigen tests (UATs) for S. pneumoniae and L. pneumophila have emerged as powerful tools for improving the diagnosis of bacterial respiratory infections, enabling physicians to administer early directed therapy and improve antimicrobial stewardship. UATs are simple, rapid, and non-invasive diagnostic tests with high specificity (>90%) and moderate sensitivity (<80%). The potential impact of urinary antigen testing is especially significant for respiratory infections caused by Legionella. While all recommended community-acquired pneumonia (CAP) therapies are adequate for treating pneumococcal pneumonia, only certain antibiotics are effective against Legionella. Delayed therapy for Legionella is associated with worse clinical outcomes, which underscores the importance of rapid diagnostic methods like UATs. Despite their potential impact, current American Thoracic Society and Infectious Diseases Society of America (ATS/IDSA) guidelines argue against the routine use of urinary antigen testing for S. pneumoniae and L. pneumophila, except in patients with severe CAP and those with epidemiological risk factors for Legionella. Further research is necessary to evaluate the impact of early targeted treatment due to positive UAT results, as well as optimal strategies for UAT utilization. The purpose of this review is to summarize the UATs available for bacterial respiratory infections, describe current guidelines on their usage, and assess their impact on clinical outcomes and targeted therapy.

Impact of Streptococcus pneumoniae Urinary Antigen Testing in Patients With Community-Acquired Pneumonia Admitted Within a Large Academic Health System

Background

Limited data support use of pneumococcal urinary antigen testing (PUAT) for patients with community-acquired pneumonia (CAP) as an antimicrobial stewardship tool. At our institution, CAP guidelines and admission order set were standardized to include universal PUAT.

Methods

This was a retrospective study of adults hospitalized in 2019 who had PUAT performed. We compared incidence and timing of de-escalation in PUAT- positive vs -negative groups and described patients’ outcomes.

Results

We evaluated 910 patients, 121 (13.3%) of whom were PUAT positive. No difference in baseline characteristics, including severity of illness, was observed between groups. Initial de-escalation occurred in 82.9% and 81.2% of PUAT-positive and -negative patients, respectively (P = .749). Median time to de-escalation was shorter in the PUAT-positive group (1 [interquartile range {IQR}, 0–2] day vs 1 [IQR, 1–2] day, P = .01). Within 24 hours of PUAT, more patients in the PUAT-positive group had atypical coverage discontinued (61.3% vs 47.2%, P = .026) without difference in methicillin-resistant Staphylococcus aureus (MRSA) agent discontinuation (or antipseudomonal de-escalation). Among the PUAT-positive group, unadjusted analysis demonstrated shorter median length of stay in patients who were de-escalated compared to those who were not (6 [IQR, 4–10] vs 8 [IQR, 7–12] days, P = .0005), without difference in the incidence of Clostridioides difficile, in-hospital mortality, or 30-day infection-related readmission.

Conclusions

We observed earlier de-escalation in the PUAT-positive group. This seems to be due to discontinuation of atypical rather than anti-MRSA or antipseudomonal coverage. Further antimicrobial stewardship interventions are warranted.

Pneumococcal Urinary Antigen Testing in United States Hospitals: A Missed Opportunity for Antimicrobial Stewardship

BACKGROUND

The Infectious Diseases Society of America recommends pneumococcal urinary antigen testing (UAT) when identifying pneumococcal infection would allow for antibiotic de-escalation. However, the frequencies of UAT and subsequent antibiotic de-escalation are unknown.

METHODS

We conducted a retrospective cohort study of adult patients admitted with community-acquired or healthcare-associated pneumonia to 170 US hospitals in the Premier database from 2010 to 2015, to describe variation in UAT use, associations of UAT results with antibiotic de-escalation, and associations of de-escalation with outcomes.

RESULTS

Among 159 894 eligible admissions, 24 757 (15.5%) included UAT performed (18.4% of intensive care unit [ICU] and 15.3% of non-ICU patients). Among hospitals with ≥100 eligible patients, UAT proportions ranged from 0% to 69%. Compared to patients with negative UAT, 7.2% with positive UAT more often had a positive Streptococcus pneumoniae culture (25.4% vs 1.9%, P < .001) and less often had resistant bacteria (5.2% vs 6.8%, P < .05). Of patients initially treated with broad-spectrum antibiotics, most were still receiving broad-spectrum therapy 3 days later, but UAT-positive patients more often had coverage narrowed (38.4% vs 17.0% UAT-negative and 14.6% untested patients, P < .001). Hospital rate of UAT was strongly correlated with de-escalation following a positive test. Only 3 patients de-escalated after a positive UAT result were subsequently admitted to ICU.

CONCLUSIONS

UAT is not ordered routinely in pneumonia, even in ICU. A positive UAT result was associated with less frequent resistant organisms, but usually did not lead to antibiotic de-escalation. Increasing UAT and narrowing therapy after a positive UAT result are opportunities for improved antimicrobial stewardship.

Effectiveness of Streptococcus Pneumoniae Urinary Antigen Testing in Decreasing Mortality of COVID-19 Co-Infected Patients: A Clinical Investigation

Background and objectives: Streptococcus pneumoniae urinary antigen (u-Ag) testing has recently gained attention in the early diagnosis of severe and critical acute respiratory syndrome coronavirus-2/pneumococcal co-infection. The aim of this study is to assess the effectiveness of Streptococcus pneumoniae u-Ag testing in coronavirus disease 2019 (COVID-19) patients, in order to assess whether pneumococcal co-infection is associated with different mortality rate and hospital stay in these patients. Materials and Methods: Charts, protocols, mortality, and hospitalization data of a consecutive series of COVID-19 patients admitted to a tertiary hospital in northern Italy during COVID-19 outbreak were retrospectively reviewed. All patients underwent Streptococcus pneumoniae u-Ag testing to detect an underlying pneumococcal co-infection. Covid19+/u-Ag+ and Covid19+/u-Ag- patients were compared in terms of overall survival and length of hospital stay using chi-square test and survival analysis. Results: Out of 575 patients with documented pneumonia, 13% screened positive for the u-Ag test. All u-Ag+ patients underwent treatment with Ceftriaxone and Azithromycin or Levofloxacin. Lopinavir/Ritonavir or Darunavir/Cobicistat were added in 44 patients, and hydroxychloroquine and low-molecular-weight heparin (LMWH) in 47 and 33 patients, respectively. All u-Ag+ patients were hospitalized. Mortality was 15.4% and 25.9% in u-Ag+ and u-Ag- patients, respectively (p = 0.09). Survival analysis showed a better prognosis, albeit not significant, in u-Ag+ patients. Median hospital stay did not differ among groups (10 vs. 9 days, p = 0.71). Conclusions: The routine use of Streptococcus pneumoniae u-Ag testing helped to better target antibiotic therapy with a final trend of reduction in mortality of u-Ag+ COVID-19 patients having a concomitant pneumococcal infection. Randomized trials on larger cohorts are necessary in order to draw definitive conclusion.

Performance of pneumococcal urinary antigen test in patients with community-onset pneumonia: a propensity score-matching study

BACKGROUND/AIMS

Although pneumococcal urinary antigen tests (PUATs) have universally been used for the diagnosis of pneumococcal pneumonia, data on the efficacy of these exams are limited. The objective of our study was to investigate the clinical impact of the PUAT in patients with community-onset pneumonia (CO-pneumonia).

METHODS

We conducted a retrospective cohort study of patients diagnosed with CO-pneumonia. Patients were classified according to their PUAT results and were matched using the propensity score-matching method. The primary outcome was 30-day mortality.

RESULTS

A total of 1,257 patients were identified and 163 (13.0%) demonstrated positive PUAT results. The sensitivity and specificity values of PUAT for overall pneumococcal pneumonia were 56.5% and 91.4%, respectively. In the full cohort, there were no significant differences in 30-day mortality between the two groups (6.1% in the positive PUAT group vs. 8.2% in the negative PUAT group, p = 0.357). However, in the propensity-matched cohort, the 30-day mortality rates were lower in the positive PUAT group (5.6% vs. 17.4%, p = 0.001). With respect to secondary outcomes, the proportion of patients with potentially drug-resistant pathogens, changes in antibiotics, and failure rates of initial antibiotic therapy were significantly lower in the positive PUAT group than in the negative PUAT group of the propensity-matched cohort.

CONCLUSION

We found that the sensitivity of the index test was low and specificity was high in this clinical setting. And our findings suggest that positive PUAT results may be associated with favorable clinical outcomes in patients with CO-pneumonia.

Determinants of empirical antipseudomonal antibiotic prescription for adults with pneumonia in the emergency department

Background

Antipseudomonal antibiotics should be restricted to patients at risk of Pseudomonas aeruginosa infection. However, the indications in different guidelines on community-acquired pneumonia (CAP) are discordant. Our objectives were to assess the prevalence of antipseudomonal antibiotic prescriptions and to identify determinants of empirical antibiotic choices in the emergency department.

Methods

Observational, retrospective, one-year cohort study in hospitalized adults with pneumonia. Antibiotic choices and clinical and demographic data were recorded on a standardized form. Antibiotics with antipseudomonal activity were classified into two groups: a) β-lactam antipseudomonals (β-APS), including carbapenems, piperacillin / tazobactam or cefepime (in monotherapy or combination) and b) monotherapy with antipseudomonal quinolones.

Results

Data were recorded from 549 adults with pneumonia, with Pseudomonas aeruginosa being isolated in only nine (1.6%). Most (85%) prescriptions were compliant with SEPAR guidelines and 207 (37%) patients received antibiotics with antipseudomonal activity (14% β-APS and 23% levofloxacin). The use of β-APS was independently associated with ICU admission (OR 8.16 95% CI 3.69–18.06) and prior hospitalization (OR 6.76 95% CI 3.02–15.15), while levofloxacin was associated with negative pneumococcal urine antigen tests (OR 3.41 95% CI 1.70–6.85) but negatively associated with ICU admission (OR 0.26 95% CI 0.08–0.86). None of these factors were associated with P aeruginosa episodes. In univariate analysis, prior P aeruginosa infection/colonization (2/9 vs 6/372, p = 0.013), severe COPD (3/9 vs 26/372, p = 0.024), multilobar involvement (7/9 vs 119/372, p = 0.007) and prior antibiotic (6/9 vs 109/372, p = 0.025) were significantly associated with P aeruginosa episodes.

Conclusions

Antipseudomonal prescriptions were common, in spite of the very low incidence of Pseudomonas aeruginosa. The rationale for prescription was influenced by both severity-of-illness and pneumococcal urine antigen test (levofloxacin) and prior hospitalization and ICU admission (β-APS). However, these factors were not associated with P aeruginosa episodes. Only prior P aeruginosa infection/colonization and severe COPD seem to be reliable indicators in clinical practice.

Impact of antimicrobial de-escalation on mortality: a literature review of study methodology and recommendations for observational studies

Introduction: The safety of de-escalation of empirical antimicrobial therapy is largely based on observational data, with many reporting protective effects on mortality. As there is no plausible biological explanation for this phenomenon, it is most probably caused by confounding by indication.Areas covered: We evaluate the methodology used in observational studies on the effects of de-escalation of antimicrobial therapy on mortality. We extended the search for a recent systematic review and identified 52 observational studies. The heterogeneity in study populations was large. Only 19 (36.5%) studies adjusted for confounders and four (8%) adjusted for clinical stability during admission, all as a fixed variable. All studies had methodological limitations, most importantly the lack of adjustment for clinical stability, causing bias toward a protective effect.Expert opinion: The methodology used in studies evaluating the effects of de-escalation on mortality requires improvement. We depicted all potential confounders in a directed acyclic graph to illustrate all associations between exposure (de-escalation) and outcome (mortality). Clinical stability is an important confounder in this association and should be modeled as a time-varying variable. We recommend to include de-escalation as time-varying exposure and use inverse-probability-of-treatment weighted marginal structural models to properly adjust for time-varying confounders.

Urinary antigen testing for pneumococcal pneumonia: is there evidence to make its use uncommon in clinical practice?

Microbiological confirmation of pneumonia caused by Streptococcus pneumoniae remains challenging as culture from blood or pleural fluid is positive in only 15–30% cases. It was hoped that a commercially available urine antigen test would improve diagnosis and consequently patient care, with improved antimicrobial stewardship. Urine antigen testing for pneumococcal pneumonia is recommended in current British Thoracic Society guidelines, whilst the National Institute for Health and Care Excellence and The American Thoracic Society and the Infectious Diseases Society of America guidelines consider its usage. Urine antigen testing is therefore widely used in hospital medicine. The assay is noninvasive, simple and culture-independent, producing a result within 15 min. Whilst initial evidence suggested urine antigen testing had a high sensitivity, recently data have suggested the actual sensitivity is lower than expected, at approximately 60–65%. Evidence has also emerged indicating that clinicians infrequently rationalise antibiotics following positive urine antigen testing, with multiple publications evaluating the role of urine antigen testing in clinical care. Furthermore, urine antigen testing does not appear to lead to any cost saving or reduction in length of hospital stay. We therefore conclude that the pneumococcal urinary antigen test does not alter patient management and leads to no cost saving, and has a lower than expected accuracy. Therefore, it may be time to make its use uncommon in clinical practice.

This article reviews the pneumococcal urine antigen test (Pn UAT), recommended in BTS, NICE and ATS/IDSA guidelines. Pn UAT is less accurate than expected, and has not been shown to improve patient care or antimicrobial stewardship or lead to cost saving.http://bit.ly/2MJpjWL

A positive pneumococcal urinary antigen test promotes narrow spectrum antibiotic use in patients with non-invasive pneumococcal pneumonia

BACKGROUND

We compared changes in antibiotics in patients diagnosed with noninvasive pneumococcal pneumonia (NPP) by pneumoccocal urinary antigen tests or respiratory cultures.

METHODS

We compared patients diagnosed by pneumococcal urinary antigen tests or respiratory cultures that grew Streptococcus pneumoniae. We assessed the time from sample receipt to final result and antibiotic regimens, including an Antibiotic Spectrum Index (ASI).

RESULTS

Seventy-two cases of NPP were diagnosed by pneumococcal urinary antigen and 87 by respiratory cultures, with a median time from sample receipt to final result of 0.21 days (interquartile range (IQR) 0.17-1.17) and 3.21 days (IQR 3.17-4.21 days), respectively. Among 123 cases without antibiotic allergies, between days 0 and 2, the ASI decreased in 36% (18/50) of cases diagnosed by urinary antigen compared to 10% (7/73) of cases diagnosed by respiratory culture (P < 0.01).

CONCLUSIONS

Positive pneumococcal urinary antigen tests lead to early deescalation of antibiotics more frequently than respiratory cultures.

Confounding by indication of the safety of de-escalation in community-acquired pneumonia: A simulation study embedded in a prospective cohort

Observational studies have demonstrated that de-escalation of antimicrobial therapy is independently associated with lower mortality. This most probably results from confounding by indication. Reaching clinical stability is associated with the decision to de-escalate and with survival. However, studies rarely adjust for this confounder. We quantified the potential confounding effect of clinical stability on the estimated impact of de-escalation on mortality in patients with community-acquired pneumonia. Data were used from the Community-Acquired Pneumonia immunization Trial in Adults (CAPiTA). The primary outcome was 30-day mortality. We performed Cox proportional-hazards regression with de-escalation as time-dependent variable and adjusted for baseline characteristics using propensity scores. The potential impact of unmeasured confounding was quantified through simulating a variable representing clinical stability on day three, using data on prevalence and associations with mortality from the literature. Of 1,536 included patients, 257 (16.7%) were de-escalated, 123 (8.0%) were escalated and in 1156 (75.3%) the antibiotic spectrum remained unchanged. Crude 30-day mortality was 3.5% (9/257) and 10.9% (107/986) in the de-escalation and continuation groups, respectively. The adjusted hazard ratio of de-escalation for 30-day mortality (compared to patients with unchanged coverage), without adjustment for clinical stability, was 0.39 (95%CI: 0.19–0.79). If 90% to 100% of de-escalated patients were clinically stable on day three, the fully adjusted hazard ratio would be 0.56 (95%CI: 0.27–1.12) to 1.04 (95%CI: 0.49–2.23), respectively. The simulated confounder was substantially stronger than any of the baseline confounders in our dataset. Quantification of effects of de-escalation on patient outcomes without proper adjustment for clinical stability results in strong negative bias. This study suggests the effect of de-escalation on mortality needs further well-designed prospective research to determine effect size more accurately.

Pneumococcal and Legionella Urinary Antigen Tests in Community-acquired Pneumonia: Prospective Evaluation of Indications for Testing

BACKGROUND

Adult, community-acquired pneumonia (CAP) guidelines from the Infectious Diseases Society of America (IDSA) and American Thoracic Society (ATS) include indications for urinary antigen tests (UATs) for Streptococcus pneumoniae (SP) and Legionella pneumophila (LP). These recommendations were based on expert opinions and have not been rigorously evaluated.

METHODS

We used data from a multicenter, prospective, surveillance study of adults hospitalized with CAP to evaluate the sensitivity and specificity of the IDSA/ATS UAT indications for identifying patients who test positive. SP and LP UATs were completed on all included patients. Separate analyses were completed for SP and LP, using 2-by-2 contingency tables, comparing the IDSA/ATS indications (UAT recommended vs not recommended) and UAT results (positive vs negative). Additionally, logistic regression was used to evaluate the association of each individual criterion in the IDSA/ATS indications with positive UAT results.

RESULTS

Among 1941 patients, UATs were positive for SP in 81 (4.2%) and for LP in 32 (1.6%). IDSA/ATS indications had 61% sensitivity (95% confidence interval [CI] 49-71%) and 39% specificity (95% CI 37-41%) for SP, and 63% sensitivity (95% CI 44-79%) and 35% specificity (95% CI 33-37%) for LP. No clinical characteristics were strongly associated with positive SP UATs, while features associated with positive LP UATs were hyponatremia, fever, diarrhea, and recent travel.

CONCLUSIONS

Recommended indications for SP and LP urinary antigen testing in the IDSA/ATS CAP guidelines have poor sensitivity and specificity for identifying patients with positive tests; future CAP guidelines should consider other strategies for determining which patients should undergo urinary antigen testing.

How can we improve clinical research in pneumonia?

PURPOSE OF REVIEW

The primary challenges in the field of clinical research include a lack of support within existing infrastructure, insufficient number of clinical research training programs and a paucity of qualified mentors. Most medical centers offer infrastructure support for investigators working with industry sponsors or government-funded clinical trials, yet there are a significant amount of clinical studies performed in the field of pneumonia which are observational studies. For this type of research, which is frequently unfunded, support is usually lacking.

RECENT FINDINGS

In an attempt to optimize clinical research in pneumonia, at the University of Louisville, we developed a clinical research coordinating center (CRCC). The center manages clinical studies in the field of respiratory infections, with the primary focus being pneumonia. Other activities of the CRCC include the organization of an annual clinical research training course for physicians and other healthcare workers, and the facilitation of international research mentoring by a process of connecting new pneumonia investigators with established clinical investigators.

SUMMARY

To improve clinical research in pneumonia, institutions need to have the appropriate infrastructure in place to support investigators in all aspects of the clinical research process.

Factors Associated With Pneumonia Severity in Children: A Systematic Review

Community-acquired pneumonia in children is associated with significant morbidity and mortality; however, data are limited in predicting which children will have negative outcomes, including clinical deterioration, severe disease, or development of complications. The Pediatric Infectious Diseases Society/Infectious Diseases Society of America (PIDS/IDSA) pediatric pneumonia guideline includes criteria that were modified from adult criteria and define pneumonia severity to assist with resource allocation and site-of-care decision-making. However, the PIDS/IDSA criteria have not been formally developed or validated in children. Definitions for mild, moderate, and severe pneumonia also vary across the literature, further complicating the development of standardized severity criteria. This systematic review summarizes (1) the current state of the evidence for defining and predicting pneumonia severity in children as well as (2) emerging evidence focused on risk stratification of children with pneumonia.

Prognostic value of pneumococcal urinary antigen test in community-acquired pneumonia

Background

The pneumococcal urinary antigen test (UAT) has been known to improve sensitivity and specificity for the diagnosis of pneumococcal pneumonia. Associations of UAT results with prognosis in community acquired pneumonia (CAP) are not known. We hypothesized that positive UAT is associated with a good prognosis, and incorporation of UAT into CRB65 would improve its prognostic performance.

Methods

In this registry-based retrospective study, we analyzed CAP patients over a 10-year period beginning in April 2008. Patients who had UAT results were included in multivariable extended Cox-regression analyses to determine the association between UAT positivity and 30-day mortality. UAT results were incorporated for patients with a CRB65 score of 1 by subtracting 1 from the scoring system if the test was positive. The performance of the modified scoring systems was assessed with area under the receiver operating characteristic (AUROC) curves.

Results

Among 5145 CAP patients, total 2280 patients had UAT results and were included in analyses. A positive UAT result was associated with a good prognosis after a week of hospitalization (aHR, 0.14; p = 0.007). After modification of CRB65 using UAT results, positive and negative predictive values for 30-day mortality were increased from 7.7 to 8.3 (p<0.001) and 98.9 to 99.1 (p = 0.010). The AUROC increased from 0.73 to 0.75 (p<0.001).

Conclusions

Positive results on UAT could be considered as a good prognostic factor in CAP. UAT could be used as a useful tool in deciding whether to refer patients to the hospital, especially in moderate CAP with a CRB score of 1.