Risk score for predicting mortality including urine lipoarabinomannan detection in hospital inpatients with HIV-associated tuberculosis in sub-Saharan Africa: Derivation and external validation cohort study

BACKGROUND

The prevalence of and mortality from HIV-associated tuberculosis (HIV/TB) in hospital inpatients in Africa remains unacceptably high. Currently, there is a lack of tools to identify those at high risk of early mortality who may benefit from adjunctive interventions. We therefore aimed to develop and validate a simple clinical risk score to predict mortality in high-burden, low-resource settings.

METHODS AND FINDINGS

A cohort of HIV-positive adults with laboratory-confirmed TB from the STAMP TB screening trial (Malawi and South Africa) was used to derive a clinical risk score using multivariable predictive modelling, considering factors at hospital admission (including urine lipoarabinomannan [LAM] detection) thought to be associated with 2-month mortality. Performance was evaluated internally and then externally validated using independent cohorts from 2 other studies (LAM-RCT and a Médecins Sans Frontières [MSF] cohort) from South Africa, Zambia, Zimbabwe, Tanzania, and Kenya. The derivation cohort included 315 patients enrolled from October 2015 and September 2017. Their median age was 36 years (IQR 30-43), 45.4% were female, median CD4 cell count at admission was 76 cells/μl (IQR 23-206), and 80.2% (210/262) of those who knew they were HIV-positive at hospital admission were taking antiretroviral therapy (ART). Two-month mortality was 30% (94/315), and mortality was associated with the following factors included in the score: age 55 years or older, male sex, being ART experienced, having severe anaemia (haemoglobin < 80 g/l), being unable to walk unaided, and having a positive urinary Determine TB LAM Ag test (Alere). The score identified patients with a 46.4% (95% CI 37.8%-55.2%) mortality risk in the high-risk group compared to 12.5% (95% CI 5.7%-25.4%) in the low-risk group (p < 0.001). The odds ratio (OR) for mortality was 6.1 (95% CI 2.4-15.2) in high-risk patients compared to low-risk patients (p < 0.001). Discrimination (c-statistic 0.70, 95% CI 0.63-0.76) and calibration (Hosmer-Lemeshow statistic, p = 0.78) were good in the derivation cohort, and similar in the external validation cohort (complete cases n = 372, c-statistic 0.68 [95% CI 0.61-0.74]). The validation cohort included 644 patients between January 2013 and August 2015. Median age was 36 years, 48.9% were female, and median CD4 count at admission was 61 (IQR 21-145). OR for mortality was 5.3 (95% CI 2.2-9.5) for high compared to low-risk patients (complete cases n = 372, p < 0.001). The score also predicted patients at higher risk of death both pre- and post-discharge. A simplified score (any 3 or more of the predictors) performed equally well. The main limitations of the scores were their imperfect accuracy, the need for access to urine LAM testing, modest study size, and not measuring all potential predictors of mortality (e.g., tuberculosis drug resistance).

CONCLUSIONS

This risk score is capable of identifying patients who could benefit from enhanced clinical care, follow-up, and/or adjunctive interventions, although further prospective validation studies are necessary. Given the scale of HIV/TB morbidity and mortality in African hospitals, better prognostic tools along with interventions could contribute towards global targets to reduce tuberculosis mortality.

Outcomes of HIV-associated pneumocystis pneumonia at a South African referral hospital

HIV-associated pneumocystis pneumonia (PCP) is increasingly recognized as an important cause of severe respiratory illness in sub-Saharan Africa. Outcomes of HIV-infected patients with PCP, especially those requiring intensive care unit (ICU) admission, have not been adequately studied in sub-Saharan Africa. The aim of this study was to describe the clinical phenotype and outcomes of HIV-associated PCP in a group of hospitalized South African patients, and to identify predictors of mortality. We conducted a retrospective record review at an academic referral center in Cape Town. HIV-infected patients over the age of 18 years with definite (any positive laboratory test) or probable PCP (defined according to the WHO/CDC clinical case definition) were included. The primary outcome measure was 90-day mortality. Logistic regression and Cox proportional hazards models were constructed to identify factors associated with mortality. We screened 562 test requests between 1 May 2004 and 31 April 2015; 124 PCP cases (68 confirmed and 56 probable) were included in the analysis. Median age was 34 years (interquartile range, IQR, 29 to 41), 89 (72%) were female, and median CD4 cell count was 26 cells/mm3 (IQR 12 to 70). Patients admitted to the ICU (n = 42) had more severe impairment of gas exchange (median ratio of arterial to inspired oxygen (PaO2:FiO2) 158 mmHg vs. 243 mmHg, p < 0.0001), and increased markers of systemic inflammation compared to those admitted to the ward (n = 82). Twenty-nine (23.6%) patients were newly-diagnosed with tuberculosis during their admission. Twenty-six (61.9%) patients admitted to ICU and 21 (25.9%) admitted to the ward had died at 90-days post-admission. Significant predictors of 90-day mortality included PaO2:FiO2 ratio (aOR 3.7; 95% CI, 1.1 to 12.9 for every 50 mgHg decrease), serum LDH (aOR 2.1; 95% CI, 1.1 to 4.1 for every 500 U/L increase), and concomitant antituberculosis therapy (aOR 82; 95% CI, 1.9 to 3525.4; P = 0.021). PaO2:FiO2 < 100 mmHg was significantly associated with inpatient death (aHR 3.8; 95% CI, 1.6 to 8.9; P = 0.003). HIV-associated PCP was associated with a severe clinical phenotype and high rates of tuberculosis co-infection. Mortality was high, particularly in patients admitted to the ICU, but was comparable to other settings. Prognostic indictors could be used to inform ICU admission policy for patients with this condition.

Risk factors for mortality from pneumocystis carinii pneumonia (PCP) in non-HIV patients: a meta-analysis

The number of patients with non-human immunodeficiency virus (HIV) related pneumocystis carinii pneumonia (PCP) is increasing with widespread immunosuppressive treatment. We performed a meta-analysis to describe the clinical characteristics and factors associated with outcomes of PCP in HIV-negative patients. A total of 13 studies including 867 patients with non-HIV related PCP was included. The overall mortality for non-HIV patients with PCP was 30.6%. The most common underlying disorder for the development of PCP is hematological malignancies (29.1%), followed by autoimmune disease (20.1%), organ or bone marrow transplantation (14.0%), and solid tumors (6.0%). Risk factors associated with increased mortality rate including old age, female sex, longer time from onset of symptoms to diagnosis, respiratory failure, solid tumors, high lactate dehydrogenase, low serum albumin, bacterial, and aspergillus co-infection, etc (P < 0.05). Adjunctive corticosteroid and PCP prophylaxis was not shown to improve the outcome of PCP in non-HIV patients (P > 0.05). Our findings indicate that mortality in non-HIV patients with PCP is high. Improved knowledge about the prognostic factors may guide the early treatment.

Immunization with Pneumocystis Cross-Reactive Antigen 1 (Pca1) Protects Mice against Pneumocystis Pneumonia and Generates Antibody to Pneumocystis jirovecii

Pneumocystis pneumonia (PcP) is a life-threatening infection that affects immunocompromised individuals. Nearly half of all PcP cases occur in those prescribed effective chemoprophylaxis, suggesting that additional preventive methods are needed. To this end, we have identified a unique mouse Pneumocystis surface protein, designated Pneumocystis cross-reactive antigen 1 (Pca1), as a potential vaccine candidate. Mice were immunized with a recombinant fusion protein containing Pca1. Subsequently, CD4⁺ T cells were depleted, and the mice were exposed to Pneumocystis murina Pca1 immunization completely protected nearly all mice, similar to immunization with whole Pneumocystis organisms. In contrast, all immunized negative-control mice developed PcP. Unexpectedly, Pca1 immunization generated cross-reactive antibody that recognized Pneumocystis jirovecii and Pneumocystis carinii Potential orthologs of Pca1 have been identified in P. jirovecii Such cross-reactivity is rare, and our findings suggest that Pca1 is a conserved antigen and potential vaccine target. The evaluation of Pca1-elicited antibodies in the prevention of PcP in humans deserves further investigation.

Treatment of Pneumocystis pneumonia with intermediate-dose and step-down to low-dose trimethoprim-sulfamethoxazole: lessons from an observational cohort study

Background

The recommended treatment of Pneumocystis jirovecii pneumonia (PCP) is high-dose trimethoprim–sulfamethoxazole (TMP–SMX) in an equivalent of TMP 15–20 mg/kg/day and SMX 75–100 mg/kg/day for 2 or 3 weeks. High rates of adverse events are reported with this dose, which raises the question if lower doses are possible.

Methods

All adult patients diagnosed with PCP in various immune dysfunctions and treated with TMP–SMX between January 1, 2003 and July 1, 2013 in a tertiary university hospital were included. Per institutional protocol, patients initiated treatment on intermediate-dose TMP–SMX (TMP 10–15 mg/kg/day) and could be stepped down to low-dose TMP–SMX (TMP 4–6 mg/kg/day) during treatment. Clinical variables at presentation, relapse rate and mortality rates were compared between intermediate- and step-down treatment groups by uni- and multivariate analyses.

Results

A total of 104 patients were included. Twenty-four patients (23 %) were switched to low-dose TMP–SMX after a median of 4.5 days (IQR 2.8–7.0 days). One relapse (4 %) occurred in the step-down group versus none in the intermediate-dose group. The overall 30-day mortality was 13 %. There was 1 death in the step-down group (4 %) compared to 13 deaths (16 %) in the intermediate-dose group.

Conclusions

We observed high cure rates of PCP by treatment with intermediate-dose TMP–SMX. In addition, a step-down strategy to low-dose TMP–SMX during treatment in selected patients appears to be safe and does not compromise the outcome of treatment.

Pneumocystis Pneumonia in Human Immunodeficiency Virus-infected Adults and Adolescents: Current Concepts and Future Directions

Pneumocystis jirovecii pneumonia (PCP) is one of the most common opportunistic infections in human immunodeficiency virus–infected adults. Colonization of Pneumocystis is highly prevalent among the general population and could be associated with the transmission and development of PCP in immunocompromised individuals. Although the microscopic demonstration of the organisms in respiratory specimens is still the golden standard of its diagnosis, polymerase chain reaction has been shown to have a high sensitivity, detecting Pneumocystis DNA in induced sputum or oropharyngeal wash. Serum β-D-glucan is useful as an adjunctive tool for the diagnosis of PCP. High-resolution computed tomography, which typically shows diffuse ground-glass opacities, is informative for the evaluation of immunocompromised patients with suspected PCP and normal chest radiography. Trimethoprim–sulfamethoxazole (TMP-SMX) is the first-line agent for the treatment of mild to severe PCP, although it is often complicated with various side effects. Since TMP-SMX is widely used for the prophylaxis, the putative drug resistance is an emerging concern.

Clinical and immunologic predictors of death after an acute opportunistic infection: results from ACTG A5164

BACKGROUND

In the pre-antiretroviral therapy (ART) era, markers of increased disease severity during an acute opportunistic infection (OI) were associated with mortality. Even with ART, mortality remains high during the first year after an OI in persons with advanced HIV infection, but it is unclear whether previous predictors of mortality remain valid in the current era.

OBJECTIVE

To determine clinical and immunological predictors of death after an OI.

METHODS

We used clinical data and stored plasma from ACTG A5164, a multicenter study evaluating the optimal timing of ART during a nontuberculous OI. We developed Cox models evaluating associations between clinical parameters and plasma marker levels at entry and time to death over the first 48 weeks after the diagnosis of OI. We developed multivariable models incorporating only clinical parameters, only plasma marker levels, or both.

RESULTS

The median CD4+ T-cell count in study participants at baseline was 29 cells/µL. Sixty-four percent of subjects had Pneumocystis jirovecii pneumonia (PCP). Twenty-three of 282 (8.2%) subjects died. In univariate analyses, entry mycobacterial infection, OI number, hospitalization, low albumin, low hemoglobin, lower CD4, and higher IL-8 and sTNFrII levels and lower IL-17 levels were associated with mortality. In the combined model using both clinical and immunologic parameters, the presence of an entry mycobacterial infection and higher sTNFrII levels were significantly associated with death.

CONCLUSIONS

In the ART era, clinical risk factors for death previously identified in the pre-ART era remain predictive. Additionally, activation of the innate immune system is associated with an increased risk of death following an acute OI.

A neglected epidemic: fungal infections in HIV/AIDS

Invasive fungal infections (IFIs) are a major cause of HIV-related mortality globally. Despite widespread rollout of combined antiretroviral therapy, there are still up to 1 million deaths annually from IFIs, accounting for 50% of all AIDS-related death. A historic failure to focus efforts on the IFIs that kill so many HIV patients has led to fundamental flaws in the management of advanced HIV infection. This review, based on the EMBO AIDS-Related Mycoses Workshop in Cape Town in July 2013, summarizes the current state of the-art in AIDS-related mycoses, and the key action points required to improve outcomes from these devastating infections.

Pneumocystis jirovecii genotype associated with increased death rate of HIV-infected patients with pneumonia

Comorbidities might predict presence of specific fungal genotypes.

Pneumocystis pneumonia associated with human immunodeficiency virus

Pneumocystis pneumonia (PCP) is caused by the yeastlike fungus Pneumocystis. Despite the widespread availability of specific anti-Pneumocystis prophylaxis and of combination antiretroviral therapy (ART), PCP remains a common AIDS-defining presentation. PCP is increasingly recognized among persons living in Africa. Pneumocystis cannot be cultured and bronchoalveolar lavage is the gold standard diagnostic test to diagnose PCP. Use of adjunctive biomarkers for diagnosis requires further evaluation. Trimethoprim-sulfamethoxazole remains the preferred first-line treatment regimen. In the era of ART, mortality from PCP is approximately 10% to 12%. The optimal time to start ART in a patient with PCP remains uncertain.

Recent advances in the diagnosis of Pneumocystis jirovecii pneumonia in HIV-infected adults

INTRODUCTION

Pneumocystis jirovecii pneumonia (PCP) is one of the most common opportunistic infections in HIV-infected adults. Although the microscopic demonstration of the organisms in respiratory specimens is still the golden standard of its diagnosis, recent advances in the diagnostic tools have been changing the situation.

AREAS COVERED

Colonization of Pneumocystis is highly prevalent among the general population and could be associated with the transmission and development of PCP in immunocompromised individuals. Nested or conventional polymerase chain reaction (PCR) has a high sensitivity, detecting Pneumocystis DNA in induced sputum or oropharyngeal wash, but often produces false positives. Although quantitative real-time PCR is promising for discriminating colonization from PCP, the targeted DNA sequences and the cut-off values remain to be standardized. Serum β-D-glucan is useful as an adjunctive tool for the diagnosis of PCP. High-resolution computed tomography, which typically shows diffuse ground-glass opacities, is informative for evaluation of immunocompromised patients with suspected PCP and normal chest radiography.

EXPERT OPINION

Although these new tools have been making the diagnosis of PCP less invasive and more accurate, any one of them can not make a definitive diagnosis by itself. The diagnostic criteria based on the combination of the testing ought to be established.