A Multivariable Prediction Model for Pneumocystis jirovecii Pneumonia in Hematology Patients with Acute Respiratory Failure

Pneumocystis jirovecii Pneumonia in Cancer Patients, a Lethal Yet Fully Preventable Disease: Insights From a Tertiary Cancer Center in East India

BACKGROUND

Pneumocystis jirovecii pneumonia (PCP) is an unrecognized infection in non-HIV patients, particularly those with solid and hematologic malignancies. These patients experience higher mortality rates. This study aims to describe the incidence, initial characteristics, management, and outcomes of PCP at a tertiary cancer care center.

METHODS

This retrospective observational study included all patients who underwent P. jirovecii PCR testing at our center from January 2019 to January 2022. PCP was diagnosed in PCR-positive patients. Data on demographics, treatment, and outcomes were extracted from medical records. The primary outcomes were ICU admission and 21-day mortality. Statistical analysis compared PCR-positive and PCR-negative patients, with a specific focus on lung cancer patients, and analyzed determinants of 21-day mortality in PCP patients.

RESULTS

Of the 345 patients suspected of PCP, 54 (15.7%) were diagnosed with PCP. PCP patients were generally older. None of the PCP patients were on prophylaxis, compared to 14.8% of PCR-negative patients. In lung cancer patients, age and radiotherapy within the past year were significantly associated with a PCP diagnosis. The 21-day mortality rate among PCP patients was 35.4%. Independent risk factors for mortality included age and hematologic malignancy, while recent chemotherapy and higher neutrophil counts were associated with lower mortality.

CONCLUSION

PCP is associated with the highest mortality in patients with hematologic malignancies and lung cancer. The findings underscore the importance and efficacy of prophylaxis in at-risk groups and should raise awareness for the diagnosis of PCP in overlooked populations, such as older cancer patients and those undergoing radiotherapy.

Pulmonary Complications in Hematologic Malignancies

Patients with hematologic malignancies are at risk for infectious and noninfectious pulmonary complications. An integrated diagnostic approach tailored to the patient's malignancy and treatment history and clinical presentation should be initiated with close interdisciplinary collaboration among specialists.

Clinical Characteristics and Prognosis of Patients With Severe Pneumonia With Pneumocystis jirovecii Colonization: A Multicenter, Retrospective Study

BACKGROUND

For decades, the incidence and clinical characteristics of Pneumocystis jirovecii colonization in patients with severe pneumonia was unclear.

RESEARCH QUESTION

What are the clinical features and outcomes associated with P jirovecii colonization in individuals diagnosed with severe pneumonia?

STUDY DESIGN AND METHODS

In this multicenter, retrospective, matched study, patients with severe pneumonia who underwent bronchoalveolar lavage clinical metagenomics from 2019 to 2023 in the ICUs of 17 medical centers were enrolled. Patients were diagnosed based on clinical metagenomics, pulmonary CT scans, and clinical presentations. Clinical data were collected retrospectively, and according to propensity score matching and Cox multivariate regression analysis, the prognosis of patients with P jirovecii colonization was compared with that of patients who were P jirovecii-negative.

RESULTS

A total of 40% of P jirovecii-positive patients are considered to have P jirovecii colonization. The P jirovecii colonization group had a higher proportion of patients with immunosuppression and a lower lymphocyte count than the P jirovecii-negative group. More frequent detection of cytomegalovirus, Epstein-Barr virus, human herpesvirus-6B, human herpesvirus-7, and torque teno virus in the lungs was associated with P jirovecii colonization than with P jirovecii negativity. By constructing two cohorts through propensity score matching, we incorporated codetected microorganisms and clinical features into a Cox proportional hazards model and revealed that P jirovecii colonization was an independent risk factor for mortality in patients with severe pneumonia. According to sensitivity analyses, which included or excluded codetected microorganisms, and patients not receiving trimethoprim-sulfamethoxazole treatment, similar conclusions were reached.

INTERPRETATION

Immunosuppression and a reduced lymphocyte count were identified as risk factors for P jirovecii colonization in patients with non-Pneumocystis pneumonia. More frequent detection of various viruses was observed in patients colonized with P jirovecii, and P jirovecii colonization was associated with an increased 28-day mortality in patients with severe pneumonia.

Comparative Dosing of Adjunctive Corticosteroids Therapy for Pneumocystis Pneumonia with ARDS in Non-HIV Immunocompromised Patients

Background

Adjuvant corticosteroids are effective in patients with human immunodeficiency virus (HIV)-associated Pneumocystis jirovecii pneumonia (PCP) patients, but the effectiveness of adjuvant corticosteroids in non-HIV PCP remained controversial. This study aimed to evaluate the effectiveness of standard-dose compared with low-dose steroids in non-HIV PCP patients with acute respiratory distress syndrome (ARDS).

Methods

This retrospective observational study included non-HIV PCP patients with ARDS admitted to the respiratory intensive care unit (RICU) of Beijing Chao-Yang Hospital from 2015 to 2022. Demographics, clinical characteristics, and outcomes were compared between patients receiving standard-dose and those receiving low-dose steroids. Survival times were assessed using Kaplan-Meier curves and compared with the Log rank test. Cox proportional hazards regression analysis was conducted to identify independent risk factors for 28-day and 60-day mortality.

Results

A total of 105 non-HIV PCP with ARDS were included, with 48 patients in the standard-dose steroid group (66.7% male, 50.5±12.6 years) and 57 in the low-dose steroid group (61.4% male, 55.5±14.2 years). The 60-day mortality was lower in the standard-dose group than in the low-dose group (63.2% vs 48.3%, p=0.04), while 28-day mortality showed no significant difference (50.8% vs 35.4%, p=0.11). After adjusting for confounders, standard-dose steroids reduced 28-day mortality (aHR: 0.339, 95% CI: 0.147-0.780) and 60-day mortality (aHR: 0.328, 95% CI: 0.152-0.709), particularly in patients aged <65 years, non-smokers, those requiring mechanical ventilation, with albumin<30 g/L, or a PaO2/FiO2 ratio <150 mmHg. No differences in co-infections or gastrointestinal bleeding were observed.

Conclusion

The standard-dose steroid therapy significantly reduced 28-day and 60-day mortality without major complications in the non-HIV immunocompromised population with severe PCP with ARDS. These findings highlight the potential survival benefit of standard-dose corticosteroid regimen in this population.

Strengths and limitations of molecular diagnostics for Pneumocystis jirovecii pneumonia

INTRODUCTION

While Pneumocystis pneumonia (PcP) remains a major AIDS-defining disease, the majority of cases of PcP now present in the HIV-negative cohort, causing significant mortality. PcP PCR diagnosis is not novel, and the optimal route of diagnosis remains unclear, with an imperfect reference method and complexity in result interpretation for alternative tests.

AREAS COVERED

This extensive review utilizing a literature search underpinning a recent systematic review/meta-analysis discusses the technical and clinical performance of PcP PCR, the added benefits of PCR testing, future aspects/considerations, and how PCR may be best used in clinical algorithms to provide a probability of PcP.

EXPERT OPINION

Given the current imperfect reference test for PcP, an alternative would be beneficial. Concerns over PcP PCR generating false positive results are valid but can be resolved by using positivity thresholds that drive specificity. Unfortunately, the extensive range of PCR assays complicates the provision of a PCR reference method. Combination testing incorporating PCR and B-D-Glucan, along with clinical and host risk factors, is key to understanding the individual probability of PcP. It is critical that access to PcP PCR testing is improved through technical and logistical development. Conversely, syndromic approaches including PcP need to be fully evaluated.

Development of a clinical risk score for the prediction of Pneumocystis jirovecii pneumonia in hospitalised patients

BACKGROUND

The performance and availability of invasive and non-invasive investigations for the diagnosis of Pneumocystis jirovecii pneumonia (PCP) vary across clinical settings. Estimating the pre-test probability of PCP is essential to the optimal selection and interpretation of diagnostic tests, such as the 1,3-β-D-glucan assay (BDG), for the prioritization of bronchoscopy, and to guide empiric treatment decisions. We aimed to develop a multivariable risk score to estimate the pre-test probability of PCP.

METHODS

The score was developed from a cohort of 626 individuals who underwent bronchoscopy for the purposes of identifying PCP in a Canadian tertiary-care centre, between 2015 and 2018. We conducted a nested case-control study of 57 cases and 228 unmatched controls. Demographic, clinical, laboratory, and radiological data were included in a multivariable logistic regression model to estimate adjusted odds ratios for PCP diagnosis. A clinical risk score was derived from the multivariable model and discrimination was assessed by estimating the score's receiver operating characteristic curve.

RESULTS

Participants had a median age of 60 years (interquartile range [IQR] 49-68) and 115 (40%) were female; 40 (14%) had HIV and 49 (17%) had a solid organ transplant (SOT). The risk score included prior SOT or HIV with CD4 ≤ 200/µL (+ 2), serum lactate dehydrogenase ≥ 265.5 IU/mL (+ 2), radiological pattern typical of PCP on chest x-ray (+ 2) or CT scan (+ 2.5), and PCP prophylaxis with trimethoprim-sulfamethoxazole (-3) or other antimicrobials (-2). The median score was 4 points (IQR, 2-4.5) corresponding to a 28% probability of PCP. The risk prediction model had good discrimination with a c-statistic of 0.79 (0.71-0.84). Given the operating characteristics of the BDG assay, scores ≤ 3 in patients without HIV, and ≤ 5.5 in those with HIV, paired with a negative BDG, would be expected to rule out PCP with 95% certainty.

CONCLUSION

We propose the PCP Score to estimate pre-test probability of PCP. Once validated, it should help clinicians determine which patients to refer for invasive investigations, when to rely on serological testing, and in whom to consider pre-emptive treatment.

Diagnostic limitations and challenges in current clinical guidelines and potential application of metagenomic sequencing to manage pulmonary invasive fungal infections in patients with haematological malignancies

BACKGROUND

Pulmonary invasive fungal infections (pIFI) disproportionately affect patients with haematological malignancies (HM). Establishing a rapid and accurate diagnosis of pIFI is challenging. Multiple guidelines recommend diagnostic testing of invasive fungal infections but lack consensus and may contribute to inconsistent diagnostic approaches.

OBJECTIVE

To identify key diagnostic challenges and review metagenomic sequencing data.

SOURCES

PubMed, professional consortium, and scientific society websites search to identify relevant, published, evidence-based clinical guidelines within the past 5 years. PubMed searchs for papers describing clinically relevant novel diagnostic technologies.

CONTENT

Current guidelines for patients with HM and suspected pIFI recommend chest computed tomography imaging and specimen testing with microscopic examination (including calcofluor white stain, histopathology, cytopathology, etc.), Aspergillus galactomannan, β-D-glucan, PCR, and culture, each with certain limitations. Emerging real-world data support the adjunctive use of metagenomic sequencing-based tests for the timely diagnosis of pIFI.

IMPLICATIONS

High-quality evidence from robust clinical trials is needed to determine whether guidelines should be updated to include novel diagnostic technologies. Trials should ask whether the combination of powerful novel diagnostics, such as pathogen-agnostic metagenomic sequencing technologies in conjunction with conventional testing can optimize the diagnostic yield for all potential pIFI pathogens that impact the health of patients with HM.

Interpretation of results of PCR and B-D-glucan for the diagnosis of Pneumocystis Jirovecii Pneumonia in immunocompromised adults with acute respiratory failure

BACKGROUND

The accuracy of a diagnostic test depends on its intrinsic characteristics and the disease incidence. This study aims to depict post-test probability of Pneumocystis pneumonia (PJP), according to results of PCR and Beta-D-Glucan (BDG) tests in patients with acute respiratory failure (ARF).

MATERIALS AND METHODS

Diagnostic performance of PCR and BDG was extracted from literature. Incidence of Pneumocystis pneumonia was assessed in a dataset of 2243 non-HIV immunocompromised patients with ARF. Incidence of Pneumocystis pneumonia was simulated assuming a normal distribution in 5000 random incidence samples. Post-test probability was assessed using Bayes theorem.

RESULTS

Incidence of PJP in non-HIV ARF patients was 4.1% (95%CI 3.3-5). Supervised classification identified 4 subgroups of interest with incidence ranging from 2.0% (No ground glass opacities; 95%CI 1.4-2.8) to 20.2% (hematopoietic cell transplantation, ground glass opacities and no PJP prophylaxis; 95%CI 14.1-27.7). In the overall population, positive post-test probability was 32.9% (95%CI 31.1-34.8) and 22.8% (95%CI 21.5-24.3) for PCR and BDG, respectively. Negative post-test probability of being infected was 0.10% (95%CI 0.09-0.11) and 0.23% (95%CI 0.21-0.25) for PCR and BDG, respectively. In the highest risk subgroup, positive predictive value was 74.5% (95%CI 72.0-76.7) and 63.8% (95%CI 60.8-65.8) for PCR and BDG, respectively.

CONCLUSION

Although both tests yield a high intrinsic performance, the low incidence of PJP in this cohort resulted in a low positive post-test probability. We propose a method to illustrate pre and post-test probability relationship that may improve clinician perception of diagnostic test performance according to disease incidence in predefined clinical settings.

Features and global impact of invasive fungal infections caused by Pneumocystis jirovecii: A systematic review to inform the World Health Organization fungal priority pathogens list

This systematic review evaluates the current global impact of invasive infections caused by Pneumocystis jirovecii (principally pneumonia: PJP), and was carried out to inform the World Health Organization Fungal Priority Pathogens List. PubMed and Web of Science were used to find studies reporting mortality, inpatient care, complications/sequelae, antifungal susceptibility/resistance, preventability, annual incidence, global distribution, and emergence in the past 10 years, published from January 2011 to February 2021. Reported mortality is highly variable, depending on the patient population: In studies of persons with HIV, mortality was reported at 5%-30%, while in studies of persons without HIV, mortality ranged from 4% to 76%. Risk factors for disease principally include immunosuppression from HIV, but other types of immunosuppression are increasingly recognised, including solid organ and haematopoietic stem cell transplantation, autoimmune and inflammatory disease, and chemotherapy for cancer. Although prophylaxis is available and generally effective, burdensome side effects may lead to discontinuation. After a period of decline associated with improvement in access to HIV treatment, new risk groups of immunosuppressed patients with PJP are increasingly identified, including solid organ transplant patients.

Characteristics and Prognosis Factors of Pneumocystis jirovecii Pneumonia According to Underlying Disease: A Retrospective Multicenter Study

BACKGROUND

Pneumocystis jirovecii pneumonia (PcP) remains associated with high rates of mortality, and the impact of immunocompromising underlying disease on the clinical presentation, severity, and mortality of PcP has not been adequately evaluated.

RESEARCH QUESTION

Does the underlying disease and immunosuppression causing PcP impact the outcome and clinical presentation of the disease?

STUDY DESIGN AND METHODS

In this multicenter retrospective observational study, conducted from January 2011 to December 2021, all consecutive patients admitted with a proven or probable diagnosis of PcP according to the European Organisation for Research and Treatment of Cancer consensus definitions were included to assess the epidemiology and impact of underlying immunosuppressive diseases on overall and 90-day mortality.

RESULTS

Overall, 481 patients were included in the study; 180 (37.4%) were defined as proven PcP and 301 (62.6%) were defined as probable PcP. Patients with immune-mediated inflammatory diseases (IMIDs) or solid tumors had a statistically poorer prognosis than other patients with PcP at day 90. In multivariate analysis, among the HIV-negative population, solid tumor underlying disease (OR, 5.47; 95% CI, 2.16-14.1; P < .001), IMIDs (OR, 2.19; 95% CI, 1.05-4.60; P = .037), long-term corticosteroid exposure (OR, 2.07; 95% CI, 1.03-4.31; P = .045), cysts in sputum/BAL smears (OR, 1.92; 95% CI, 1.02-3.62; P = .043), and SOFA score at admission (OR, 1.58; 95% CI, 1.39-1.82; P < .001) were independently associated with 90-day mortality. Prior corticotherapy was the only immunosuppressant associated with 90-day mortality (OR, 1.67; 95% CI, 1.03-2.71; P = .035), especially for a prednisone daily dose ≥ 10 mg (OR, 1.80; 95% CI, 1.14-2.85; P = .010).

INTERPRETATION

Among patients who were HIV-negative, long-term corticosteroid prior to PcP diagnosis was independently associated with increased 90-day mortality, specifically in patients with IMIDs. These results highlight both the needs for PcP prophylaxis in patients with IMIDs and to early consider PcP curative treatment in severe pneumonia among patients with IMIDs.

Pneumocystis jirovecii Pneumonia in a Liver Transplant Recipient With an Adverse Reaction to Trimethoprim/Sulfamethoxazole Treated With a Sulfonamide Desensitization Protocol: Case Report

BACKGROUND

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic fungal infection that, in immunocompromised patients, can progress to respiratory failure and death. Since trimethoprim/sulfamethoxazole (TMP/SMX) chemoprophylaxis has become a standard management, the prognosis has improved. However, there are patients with a history of TMP/SMX intolerance who cannot receive chemoprophylaxis.

BACKGROUND

We report on a 53-year-old male liver recipient treated with a standard triple immunosuppressive regimen in whom TMP/SMX was waived because of a history of allergy manifested as a generalized rash with edema more than 30 years ago. At transplantation, the immunologic risk was assessed as low, and liver graft function was normal. In the third month after engraftment, he developed dyspnea at rest required constant passive oxygen therapy. Ceftriaxone, azithromycin, and clindamycin were implemented. Mycophenolate acid was stopped, and tacrolimus was reduced. High-resolution computed tomography revealed interstitial pneumonia. Pneumocystis jirovecii pneumoniae was diagnosed from bronchoalveolar lavage. Instead of TMP/SMX, pentamidine and caspofungin were also used for PJP, with no improvement. After 3 weeks, the patient deteriorated. Because of his life-threatening condition, TMP/SMX was introduced in the sulfonamide desensitization protocol, including hydrocortisone and clemastinum. Within 4 days, the patient stabilized with no signs of TMP/SMX intolerance. Pneumonia subsided within a month, and TMP/SMX was prescribed lifelong.

CONCLUSIONS

Prophylaxis for PJP with TMP/SMX still remains an important issue in transplant recipients. Adverse reaction to TMP/SMX in the past is not always a contraindication to reintroducing prophylaxis. The decision of prophylaxis avoidance should be analyzed carefully; in uncertain cases, a sulfonamide desensitization protocol should be considered.

Lessons from Multiple Infections Such as Lymphoma Complicated with Pneumocystis Infection: A Case Report

Background

Lymphoma is complicated by intricate infections, notably Pneumocystis jirovecii pneumonia (PJP), marked by rapid progression, respiratory failure, and high mortality. Rapid diagnosis of PJP and effective administration of the first-line treatment trimethoprim-sulfamethoxazole (TMP-SMX) are important. For patients intolerant to TMP-SMX, selecting appropriate alternatives is challenging, necessitating careful decisions to optimize diagnosis and treatment. We present a lymphoma case complicated by PJP, illustrating medication adjustment until a positive response was observed.

Case Description

A 41-year-old male patient with lymphoma presented with a week-long history of fever, fatigue, cough, sputum, chest tightness, and exertional dyspnea, unresponsive to treatment. Routine laboratory examinations revealed no pathogenic bacteria. PJ and Mycobacterium tuberculosis (MTB) were detected in bronchoalveolar lavage fluid (BALF) using metagenomic next-generation sequencing (mNGS). On Day 1 of admission, meropenem, TMP-SMX, and rifampicin+isoniazid+levofloxacin were administered. However, the patient developed drug-induced hepatotoxicity and gastrointestinal adverse reactions after six days of treatment. After a multidisciplinary team discussion, anti-tuberculosis therapy was stopped because of insufficient evidence of tuberculosis infection. A reduced dose of TMP-SMX with micafungin was used for PJP; however, symptoms persisted and repeated computed tomography showed extensive deterioration of bilateral pulmonary plaques. The PJP regimen was modified to include a combination of TMP-SMX and caspofungin. Due to the high fever and elevated infection indices, the patient was treated with teicoplanin to enhance the anti-infection effects. By Day 13, the patient's temperature had normalized, and infection control was achieved by Day 30. CT revealed that the infection in both lung lobes fully resolved. Subsequently, lymphoma treatment commenced.

Conclusion

BALF-NGS facilitates early and rapid diagnosis of PJP. mNGS reads of MTB bacillus <5 may indicate a bacterial carrier state, warranting other detection techniques to support it. There is insufficient evidence for using TMP-SMX with micafungin to treat PJP; however, TMP-SMX combined with caspofungin is suitable.

Severe Community-Acquired Pneumonia in Immunocompromised Patients

Due to higher survival rates with good quality of life, related to new treatments in the fields of oncology, hematology, and transplantation, the number of immunocompromised patients is increasing. But these patients are at high risk of intensive care unit admission because of numerous complications. Acute respiratory failure due to severe community-acquired pneumonia is one of the leading causes of admission. In this setting, the need for invasive mechanical ventilation is up to 60%, associated with a high hospital mortality rate of around 40 to 50%. A wide range of pathogens according to the reason of immunosuppression is associated with severe pneumonia in those patients: documented bacterial pneumonia represents a third of cases, viral and fungal pneumonia both account for up to 15% of cases. For patients with an undetermined etiology despite comprehensive diagnostic workup, the hospital mortality rate is very high. Thus, a standardized diagnosis strategy should be defined to increase the diagnosis rate and prescribe the appropriate treatment. This review focuses on the benefit-to-risk ratio of invasive or noninvasive strategies, in the era of omics, for the management of critically ill immunocompromised patients with severe pneumonia in terms of diagnosis and oxygenation.

A machine learning diagnostic model for Pneumocystis jirovecii pneumonia in patients with severe pneumonia

BACKGROUND

The diagnosis of Pneumocystis jirovecii pneumonia (PCP) in patients presenting with severe pneumonia is challenging and delays in treatment were associated with worse prognosis. This study aimed to develop a rapid, easily available, noninvasive machine learning diagnostic model for PCP among patients with severe pneumonia.

METHODS

A retrospective study was performed in West China Hospital among consecutive patients with severe pneumonia who had undergone bronchoalveolar lavage for etiological evaluation between October 2010 and April 2021. Factors associated with PCP were identified and four diagnostic models were established using machine learning algorithms including Logistic Regression, eXtreme Gradient Boosting, Random Forest (RF) and LightGBM. The performance of these models were evaluated by the area under the receiver operating characteristic curve (AUC).

RESULTS

Ultimately, 704 patients were enrolled and randomly divided into a training set (n = 564) and a testing set (n = 140). Four factors were ultimately selected to establish the model including neutrophil, globulin, β-D-glucan and ground glass opacity. The RF model exhibited the greatest diagnostic performance with an AUC of 0.907. The calibration curve and decision curve analysis also demonstrated its accuracy and applicability.

CONCLUSIONS

We constructed a PCP diagnostic model in patients with severe pneumonia using four easily available and noninvasive clinical indicators. With satisfying diagnostic performance and good clinical practicability, this model may help clinicians to make early diagnosis of PCP, reduce the delays of treatment and improve the prognosis among these patients.

Machine Learning Models for Prediction of Severe Pneumocystis carinii Pneumonia after Kidney Transplantation: A Single-Center Retrospective Study

BACKGROUND

The objective of this study was to formulate and validate a prognostic model for postoperative severe Pneumocystis carinii pneumonia (SPCP) in kidney transplant recipients utilizing machine learning algorithms, and to compare the performance of various models.

METHODS

Clinical manifestations and laboratory test results upon admission were gathered as variables for 88 patients who experienced PCP following kidney transplantation. The most discriminative variables were identified, and subsequently, Support Vector Machine (SVM), Logistic Regression (LR), Random Forest (RF), K-Nearest Neighbor (KNN), Light Gradient Boosting Machine (LGBM), and eXtreme Gradient Boosting (XGB) models were constructed. Finally, the models' predictive capabilities were assessed through ROC curves, sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), and F1-scores. The Shapley additive explanations (SHAP) algorithm was employed to elucidate the contributions of the most effective model's variables.

RESULTS

Through lasso regression, five features-hemoglobin (Hb), Procalcitonin (PCT), C-reactive protein (CRP), progressive dyspnea, and Albumin (ALB)-were identified, and six machine learning models were developed using these variables after evaluating their correlation and multicollinearity. In the validation cohort, the RF model demonstrated the highest AUC (0.920 (0.810-1.000), F1-Score (0.8), accuracy (0.885), sensitivity (0.818), PPV (0.667), and NPV (0.913) among the six models, while the XGB and KNN models exhibited the highest specificity (0.909) among the six models. Notably, CRP exerted a significant influence on the models, as revealed by SHAP and feature importance rankings.

CONCLUSIONS

Machine learning algorithms offer a viable approach for constructing prognostic models to predict the development of severe disease following PCP in kidney transplant recipients, with potential practical applications.

Development and Validation of a Diagnostic Nomogram for Pneumocystis jirovecii Pneumonia in Non-HIV-Infected Pneumonia Patients Undergoing Oral Glucocorticoid Treatment

Purpose

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic but potentially fatal infection with increasing prevalence in HIV-free patients. Glucocorticoid therapy is one of the most important risk factors for PJP. The delay in diagnosis contributes to poor outcomes. Hence, the aim of this study was to develop and validate a nomogram for the diagnosis of PJP in patients with non-HIV-infected pneumonia who are undergoing oral glucocorticoid treatment.

Patients and Methods

This study was a retrospective, cross-sectional research. The development group included 434 patients who were admitted with pneumonia from 6 hospitals. Demographics, symptomatic features, laboratory and computed tomography data were analyzed using the least absolute shrinkage and selection operator (LASSO) to select potential diagnostic indicators. Binary logistic regression was used to develop a diagnostic nomogram. Another 119 patients with pneumonia admitted at Sichuan Provincial People's Hospital was used as the validation group. The diagnostic performance of the nomogram was measured by area under the receiver-operating-characteristics curve (AUC), calibration curves, and the net benefit by decision curve.

Results

PJP prevalence was 25.3% in the development group. LASSO regression revealed that age, lymphocyte count, fever, dry cough, respiratory failure, ground-glass opacity in lungs, glucocorticoid therapy duration, and immunosuppressive therapy were indicators of PJP. The nomogram showed robust discrimination, with an AUC of 0.82 (95% CI 0.77-0.86) in the development group and an AUC of 0.87 (95% CI 0.80-0.94) in the validation group, both showing acceptable calibration. In the decision curve analysis, our model consistently achieved a greater net benefit across almost all ranges of clinical thresholds.

Conclusion

We developed a nomogram with good diagnostic power for PJP diagnosis in pneumonia patients receiving oral glucocorticoids. This nomogram may help promote timely treatment of PJP and thus reduce the mortality rate in these patients.

Development and validation of tools for predicting the risk of death and ICU admission of non-HIV-infected patients with Pneumocystis jirovecii pneumonia

Introduction

The mortality rate of non-HIV-infected Pneumocystis jirovecii pneumonia (PCP) is high. This research aimed to develop and validate two clinical tools for predicting the risk of death and intensive care unit (ICU) admission in non-HIV-infected patients with PCP to reduce mortality.

Methods

A retrospective study was conducted at Peking Union Medical College Hospital between 2012 and 2021. All proven and probable non-HIV-infected patients with PCP were included. The least absolute shrinkage and selection operator method and multivariable logistic regression analysis were used to select the high-risk prognostic parameters. In the validation, the receiver operating characteristic curve and concordance index were used to quantify the discrimination performance. Calibration curves were constructed to assess the predictive consistency compared with the actual observations. A likelihood ratio test was used to compare the tool and CURB-65 score.

Results

In total, 508 patients were enrolled in the study. The tool for predicting death included eight factors: age, chronic lung disease, respiratory rate, blood urea nitrogen (BUN), lactate dehydrogenase (LDH), cytomegalovirus infection, shock, and invasive mechanical ventilation. The tool for predicting ICU admission composed of the following factors: respiratory rate, dyspnea, lung moist rales, LDH, BUN, C-reactive protein/albumin ratio, and pleural effusion. In external validation, the two clinical models performed well, showing good AUCs (0.915 and 0.880) and fit calibration plots. Compared with the CURB-65 score, our tool was more informative and had a higher predictive ability (AUC: 0.880 vs. 0.557) for predicting the risk of ICU admission.

Conclusion

In conclusion, we developed and validated tools to predict death and ICU admission risks of non-HIV patients with PCP. Based on the information from the tools, clinicians can tailor appropriate therapy plans and use appropriate monitoring levels for high-risk patients, eventually reducing the mortality of those with PCP.

An overview of using fungal DNA for the diagnosis of invasive mycoses

INTRODUCTION

Fungal PCR has undergone considerable standardization and together with the availability of commercial assays, external quality assessment schemes and extensive performance validation data, is ready for widespread use for the screening and diagnosis of invasive fungal disease (IFD).

AREAS COVERED

Drawing on the experience and knowledge of the leads of the various working parties of the Fungal PCR initiative, this review will address general considerations concerning the use of molecular tests for the diagnosis of IFD, before focussing specifically on the technical and clinical aspects of molecular testing for the main causes of IFD and recent technological developments.

EXPERT OPINION

For infections caused by Aspergillus, Candida and Pneumocystis jirovecii, PCR testing is recommended, combination with serological testing will likely enhance the diagnosis of these diseases. For other IFD (e.g. Mucormycosis) molecular diagnostics, represent the only non-classical mycological approach towards diagnoses and continued performance validation and standardization has improved confidence in such testing. The emergence of antifungal resistance can be diagnosed, in part, through molecular testing. Next-generation sequencing has the potential to significantly improve our understanding of fungal phylogeny, epidemiology, pathogenesis, mycobiome/microbiome and interactions with the host, while identifying novel and existing mechanisms of antifungal resistance and novel diagnostic/therapeutic targets.

Oxygenation Strategy During Acute Respiratory Failure in Critically-Ill Immunocompromised Patients

OBJECTIVES

To assess the response to initial oxygenation strategy according to clinical variables available at admission.

DESIGN

Multicenter cohort study.

SETTING

Thirty French and Belgium medical ICU.

SUBJECTS

Immunocompromised patients with hypoxemic acute respiratory failure.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data were extracted from the Groupe de Recherche en Reanimation Respiratoire du patient d'Onco-Hématologie database. Need for invasive mechanical ventilation was the primary endpoint. Secondary endpoint was day-28 mortality. Six-hundred forty-nine patients were included. First oxygenation strategies included standard oxygen (n = 245, 38%), noninvasive ventilation (n = 285; 44%), high-flow nasal cannula oxygen (n = 55; 8%), and noninvasive ventilation + high-flow nasal cannula oxygen (n = 64; 10%). Bilateral alveolar pattern (odds ratio = 1.67 [1.03-2.69]; p = 0.04), bacterial (odds ratio = 1.98 [1.07-3.65]; p = 0.03) or opportunistic infection (odds ratio = 4.75 [2.23-10.1]; p < 0.001), noninvasive ventilation use (odds ratio = 2.85 [1.73-4.70]; p < 0.001), Sequential Organ Failure Assessment score (odds ratio = 1.19 [1.10-1.28]; p < 0.001), and ratio of PaO2 and FIO2 less than 100 at ICU admission (odds ratio = 1.96 [1.27-3.02]; p = 0.0002) were independently associated with intubation rate. Day-28 mortality was independently associated with bacterial (odds ratio = 2.34 [1.10-4.97]; p = 0.03) or opportunistic infection (odds ratio = 4.96 [2.11-11.6]; p < 0.001), noninvasive ventilation use (odds ratio = 2.35 [1.35-4.09]; p = 0.003), Sequential Organ Failure Assessment score (odds ratio = 1.19 [1.10-1.28]; p < 0.001), and ratio of PaO2 and FIO2 less than 100 at ICU admission (odds ratio = 1.97 [1.26-3.09]; p = 0.003). High-flow nasal cannula oxygen use was neither associated with intubation nor mortality rates.

CONCLUSIONS

Some clinical characteristics at ICU admission including etiology and severity of acute respiratory failure enable to identify patients at high risk for intubation.

Prognostic impact of early adjunctive corticosteroid therapy in non-HIV oncology or haematology patients with Pneumocystis jirovecii pneumonia: A propensity score analysis

Purpose

While early adjunctive corticosteroid therapy (EACST) has been proven effective in HIV patients with Pneumocystis Jirovecii Pneumonia (PJP), data remains controversial concerning non-HIV oncology or haematology patients.

Methods

This retrospective study included cancer patients without HIV and with diagnosis of PJP admitted in a cancer referral centre, from January-1-2010 to March-31-2017. We compared 30-day and 1-year mortality rate, change in the respiratory item of the Sequential Organ Failure Assessment score(SOFA-_resp worsening), use of tracheal intubation between day-1 and day-5 of anti-pneumocystis therapy and occurrence of coinfections between patients with EACST and those with no or late corticosteroid therapy, using an inverse probability weighting propensity score-based (IPW) analysis.

Results

133 non-HIV oncology or haematology PJP patients were included (EACST n = 58, others n = 75). The main underlying conditions were haematological malignancies (n = 107, 80,5%), solid tumour (n = 27, 20,3%) and allogeneic stem cell transplantation (n = 17, 12,8%). Overall 30-day and 1-year mortality rate was 24,1% and 56,4%, respectively. IPW analysis found no difference on 30-day (HR = 1.45, 95% CI [0.7–3.04], p = 0.321) and 1-year (HR = 1.25, CI 95% [0.75–2.09], p = 0.39) mortality rate between groups.

Conclusion

No difference in SOFA-_resp worsening, tracheal intubation and coinfections was found between groups. Combination of EACST with anti-pneumocystis therapy in non-HIV onco-haematology PJP-patients was not associated with clinical improvement.

Validation of the Pneumocystis pneumonia score in haematology patients with acute respiratory failure

Background

Pneumocystis pneumonia (PCP) is an important cause of acute respiratory failure (ARF) in immunocompromised patients, yet no actual clinical tool suitably identifies patients at risk. Recently, a multivariable prediction model has been proposed for haematology patients with ARF requiring intensive care unit (ICU) admission to assess the risk of PCP (PCP score). However, it has not yet been validated externally.

Methods

To validate the PCP score, a retrospective cohort study was conducted in two large designated haematology centres in Korea. One-hundred and forty haematology patients with ARF were admitted to ICU. They underwent aetiologic evaluations between July 2016 and June 2019. The predictive ability of the score was assessed with the receiver operating characteristic (ROC) curve analysis for both the discrimination and calibration of the score.

Results

Among the 141 patients, 13 (9.2%) were finally diagnosed of PCP. Although the median of PCP score in PCP group was higher than in non-PCP group (3.0 [interquartile range 0.0–4.0] vs. 2.0 [0.5–4.0]), the difference was not statistically significant (P = 0.679). The area under the ROC curve of the PCP score in our cohort was 0.535 (95% CI, 0.449–0.620), indicating no discriminatory ability. When using a cut-off of 3.0 the score, the result was 38.5% (95% CI, 13.9–68.4) sensitive and 7.03% (95% CI, 61.6–78.1) specific. The negative predictive value was 58.8% and positive predictive value was 59.8% for a 10% prevalence of PCP.

Conclusions

In this study, the PCP score was not useful to predict the risk of PCP in haematology patients with ARF. Further prospective validation studies are needed to validate the score’s use in routine clinical practice for the early diagnosis of PCP in haematology patients.

Serum (1,3)-Beta-d-Glucan has suboptimal performance for the diagnosis of Pneumocystis jirovecii pneumonia in cancer patients and correlates poorly with respiratory burden as measured by quantitative PCR

OBJECTIVE

Non-HIV immunocompromised patients with Pneumocystis jirovecii pneumonia (PCP) have lower fungal load than those with AIDS, potentially affecting the accuracy of diagnostic biomarkers. Therefore, we investigated the performance of serum (1,3)-Beta-d-Glucan (BDG) in conjunction with quantitative Pneumocystis jirovecii PCR (qPCR) in non-HIV cancer patients.

METHODS

We reviewed records of non-HIV cancer patients and classified them as definite, probable, or possible PCP cases, according to clinicoradiological features, microscopy findings, and qPCR results in bronchoscopy specimens. We evaluated the diagnostic performance of serum BDG and its correlation with qPCR results.

RESULTS

We identified 101 PCP patients (73 definite/probable, 28 possible) and 74 controls. Correlation of BDG and qPCR was low among all 101 qPCR-positive patients (Spearman's = 0.38) and in definite/probable PCP cases (Spearman's = 0.18). Considering all qPCR-positive patients, BDG showed consistently low sensitivity at different cutoffs. Among definite/probable cases, the diagnostic accuracy of BDG remained poor, yet slightly improved with high qPCR thresholds (AUC = 0.86 at ≥2000 DNA copies/mL). BDG had a low PPV but excellent NPV across different qPCR and BDG cutoffs.

CONCLUSIONS

BDG and qPCR levels correlate poorly in non-HIV cancer patients with PCP. BDG diagnostic performance is suboptimal but a negative test may be useful to rule out PCP in this population.

Identifying predictors for bacterial and fungal coinfection on chest computed tomography in patients with Pneumocystis pneumonia

BACKGROUND

Pneumocystis pneumonia (PCP) is a common opportunistic infection with high mortality in individuals with decreased immunity. Pulmonary coinfections with PCP are associated with poor prognosis. The study aims to identify radiological predictors for pulmonary coinfections in patients with PCP and risk factors for mortality.

METHODS

This is a retrospective, five-year study was conducted in a medical center, enrolling patients diagnosed with PCP, who received a chest computed tomography (CT) scan. The radiological findings and medical records of all participants were reviewed carefully by 2 independent doctors. Univariable and multivariable analysis was performed to identify radiological predictors for pulmonary coinfection and clinical risk factors for poor prognosis.

RESULTS

A total of 101 participants were included, of which 39 were HIV-infected and 62 were non-HIV-infected. In multivariable analysis, radiologic predictors on chest CT for coinfection with bacteria pneumonia included lack of ground glass opacity (adjusted odds ratio [aOR], 6.33; 95% confidence interval [CI], 2.03-19.77; p = 0.001) and presence of pleural effusion (aOR, 3.74; 95% CI, 1.27-10.99; p = 0.017). Predictors for fungal pneumonia included diffuse consolidation (adjusted OR, 6.27; 95% CI, 1.72-22.86; p = 0.005) and presence of pleural effusion (adjusted OR, 5.26; 95% CI, 1.44-19.17; p = 0.012). A significantly higher in-hospital mortality was associated with older age, recent corticosteroid exposure, cytomegalovirus coinfection, and acute respiratory failure.

CONCLUSION

Early identification of pulmonary coinfections in PCP using radiological features on the CT scans, will enable appropriate treatment which is crucial to improve the prognosis.

High Mean Platelet Volume Associates with In-Hospital Mortality in Severe Pneumonia Patients

Background

Although mean platelet volume (MPV) appears to be associated with poor outcome of pneumonia, the relationship between MPV and in-hospital mortality is unclear in severe pneumonia (SP) patients.

Methods

In this retrospective cohort study, 115 SP patients from June 1st, 2016, to September 29th, 2019, were included and divided into two groups. The primary outcome was in-hospital mortality. The receiver operating characteristic (ROC) curve was performed to assess the predictive ability for in-hospital mortality. Kaplan-Meier cumulative incidence curves were applied to observe the incidence of mortality. Multivariable Cox regression analyses were used to evaluate the hazard ratios (HRs). Besides, a formal test for interaction was investigated to analyze the relationship between MPV and sex.

Results

During the course of hospitalization, 63 cases of mortality were recorded. ROC analysis suggested that MPV had a modest power for predicting in-hospital mortality (AUC = 0.723, 95% CI: 0.628-0.818, P < 0.001). Yet the cutoff value of MPV was 10.5 (sensitivity = 73.02%; specificity = 73.08%). Compared to the low-MPV group, the high-MPV group had significantly increased in-hospital mortality (log-rank test = 13.501, P < 0.001), while the adjusted Cox model indicated that the high-MPV group was associated with an elevated risk of in-hospital mortality (HR: 2.267, 95% CI: 1.166-4.406, P = 0.016). Moreover, analyses of in-hospital mortality suggested a significant interaction between optimal MPV level and sex (P = 0.011). In a multivariate Cox model which included females only, a high MPV level was associated with increased risk of in-hospital mortality (HR: 11.387, 95% CI: 1.767-73.380, P = 0.011).

Conclusion

High MPV level is an independent risk factor for in-hospital mortality in patients with SP.

Diagnosis of severe respiratory infections in immunocompromised patients

An increasing number of critically ill patients are immunocompromised. Acute hypoxemic respiratory failure (ARF), chiefly due to pulmonary infection, is the leading reason for ICU admission. Identifying the cause of ARF increases the chances of survival, but may be extremely challenging, as the underlying disease, treatments, and infection combine to create complex clinical pictures. In addition, there may be more than one infectious agent, and the pulmonary manifestations may be related to both infectious and non-infectious insults. Clinically or microbiologically documented bacterial pneumonia accounts for one-third of cases of ARF in immunocompromised patients. Early antibiotic therapy is recommended but decreases the chances of identifying the causative organism(s) to about 50%. Viruses are the second most common cause of severe respiratory infections. Positive tests for a virus in respiratory samples do not necessarily indicate a role for the virus in the current acute illness. Invasive fungal infections (Aspergillus, Mucorales, and Pneumocystis jirovecii) account for about 15% of severe respiratory infections, whereas parasites rarely cause severe acute infections in immunocompromised patients. This review focuses on the diagnosis of severe respiratory infections in immunocompromised patients. Special attention is given to newly validated diagnostic tests designed to be used on non-invasive samples or bronchoalveolar lavage fluid and capable of increasing the likelihood of an early etiological diagnosis.

Outcome and prognostic factors of Pneumocystis jirovecii pneumonia in immunocompromised adults: a prospective observational study

Background

Pneumocystis jirovecii pneumonia (PJP) remains a severe disease associated with high rates of invasive mechanical ventilation (MV) and mortality. The objectives of this study were to assess early risk factors for severe PJP and 90-day mortality, including the broncho-alveolar lavage fluid cytology profiles at diagnosis.

Methods

We prospectively enrolled all patients meeting pre-defined diagnostic criteria for PJP admitted at Nantes university hospital, France, from January 2012 to January 2017. Diagnostic criteria for PJP were typical clinical features with microbiological confirmation of P. jirovecii cysts by direct examination or a positive specific quantitative real-time polymerase chain reaction (PCR) assay. Severe PJP was defined as hypoxemic acute respiratory failure requiring high-flow nasal oxygen with at least 50% FiO₂, non-invasive ventilation, or MV.

Results

Of 2446 respiratory samples investigated during the study period, 514 from 430 patients were positive for P. jirovecii. Of these 430 patients, 107 met criteria for PJP and were included in the study, 53 (49.5%) patients had severe PJP, including 30 who required MV. All patients were immunocompromised with haematological malignancy ranking first (n = 37, 35%), followed by solid organ transplantation (n = 27, 25%), HIV-infection (n = 21, 20%), systemic diseases (n = 13, 12%), solid tumors (n = 12, 11%) and primary immunodeficiency (n = 6, 8%). By multivariate analysis, factors independently associated with severity were older age (OR, 3.36; 95% CI 1.4–8.5; p < 0.05), a P. jirovecii microscopy-positive result from bronchoalveolar lavage (BAL) (OR, 1.3; 95% CI 1.54–9.3; p < 0.05); and absence of a BAL fluid alveolitis profile (OR, 3.2; 95% CI 1.27–8.8; p < 0.04). The 90-day mortality rate was 27%, increasing to 50% in the severe PJP group. Factors independently associated with 90-day mortality were worse SOFA score on day 1 (OR, 1.05; 95% CI 1.02–1.09; p < 0.001) whereas alveolitis at BAL was protective (OR, 0.79; 95% CI 0.65–0.96; p < 0.05). In the subgroup of HIV-negative patients, similar findings were obtained, then viral co-infection were independently associated with higher 90-day mortality (OR, 1.25; 95% CI 1.02–1.55; p < 0.05).

Conclusions

Older age and P. jirovecii oocysts at microscopic examination of BAL were independently associated with severe PJP. Both initial PJP severity as evaluated by the SOFA score and viral co-infection predicted 90-day mortality. Alveolitis at BAL examination was associated with less severe PJP. The pathophysiological mechanism underlying this observation deserves further investigation.

Pneumocystis pneumonia in the twenty-first century: HIV-infected versus HIV-uninfected patients

Introduction: Pneumocystis pneumonia (PcP) has classically been described as a serious complication in patients infected with the human immunodeficiency virus (HIV). However, the emerging number of conditions associated with immunosuppression has led to its appearance in other patient populations. Areas covered: This article reviews the most recent publications on PcP in the HIV-infected and HIV-uninfected population, focusing on epidemiology, diagnostic, therapy and prevention. The data discussed here were mainly obtained from a non-systematic review using Medline and references from relevant articles including randomized clinical trials, meta-analyses, observational studies and clinical reviews. Expert opinion: The growing incidence of Pneumocystis infection in the HIV-uninfected population suggests the need for new global epidemiological studies in order to identify the true scale of the disease in this population. These data would allow us to improve diagnosis, therapeutic strategies, and clinical management. It is very important that both patients and physicians realize that HIV-uninfected patients are at risk of PcP and that rapid diagnosis and early initiation of treatment are associated with better prognosis. Currently, in-hospital mortality rates are very high: 15% for HIV-infected patients and 50% in some HIV-uninfected patients. Therefore, adequate preventive measures should be implemented to avoid the high mortality rates seen in recent decades.

Acute Respiratory Failure in the Oncologic Patient: New Era, New Issues

Recent decades have seen an increase in the number of patients living with cancer. This trend has resulted in an increase in intensive care unit (ICU) utilization across this population [1]. Acute respiratory failure is the most frequent medical complication leading to critical illness in oncologic patients [2–4]. Historically, there had been a reluctance to admit cancer patients to the ICU given their poor outcomes, particularly in the setting of hematologic malignancy and invasive mechanical ventilation [5]. ICU treatment limitations or refusal of admission was advocated [6]. Major advances in oncologic care, critical care and more meticulous attention to where the conditions overlap, have resulted in marked improvement in short-term survival in this population [1, 7, 8]. Despite these major advances, acute respiratory failure in this population remains complex with unique challenges surrounding diagnosis and management compared to the general ICU population. This chapter provides a comprehensive overview of acute respiratory failure in the oncologic population and highlights specific considerations for the intensivist. We will focus on the important differences between the immunocompromised oncologic patient and general intensive care population, the spectrum of causes of acute respiratory failure with a specific focus on toxicities related to newer cancer therapies, diagnostic approach, management and an up-to-date overview of prognosis.