Low-Dose TMP-SMX in the Treatment of Pneumocystis jirovecii Pneumonia: A Systematic Review and Meta-analysis

Comparative efficacy and safety of Pneumocystis jirovecii pneumonia prophylaxis regimens for people living with HIV: a systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Pneumocystis jirovecii pneumonia (PCP) is a common opportunistic infection among people living with HIV (PWH), particularly among new and untreated cases. Several regimens are available for the prophylaxis of PCP, including trimethoprim-sulfamethoxazole (TMP-SMX), dapsone-based regimens (DBRs), aerosolized pentamidine (AP), and atovaquone.

OBJECTIVES

To compare the efficacy and safety of PCP prophylaxis regimens in PWH by network meta-analysis.

METHODS

DATA SOURCES: Embase, MEDLINE, and CENTRAL from inception to June 21, 2023.

STUDY ELIGIBILITY CRITERIA

Comparative randomized controlled trials (RCTs).

PARTICIPANTS

PWH.

INTERVENTIONS

Regimens for PCP prophylaxis either compared head-to-head or versus no treatment/placebo.

ASSESSMENT OF RISK OF BIAS

Cochrane risk-of-bias tool for RCTs 2.

METHODS OF DATA SYNTHESIS

Title or abstract and full-text screening and data extraction were performed in duplicate by two independent reviewers. Data on PCP incidence, all-cause mortality, and discontinuation due to toxicity were pooled and ranked by network meta-analysis. Subgroup analyses of primary versus secondary prophylaxis, by year, and by dosage were performed.

RESULTS

A total of 26 RCTs, comprising 55 treatment arms involving 7516 PWH were included. For the prevention of PCP, TMP-SMX was ranked the most favourable agent and was superior to DBRs (risk ratio [RR] = 0.54; 95% CI, 0.36-0.83) and AP (RR = 0.53; 95% CI, 0.36-0.77). TMP-SMX was also the only agent with a mortality benefit compared with no treatment/placebo (RR = 0.79; 95% CI, 0.64-0.98). However, TMP-SMX was also ranked as the most toxic agent with a greater risk of discontinuation than DBRs (RR = 1.25; 95% CI, 1.01-1.54) and AP (7.20; 95% CI, 5.37-9.66). No significant differences in PCP prevention or mortality were detected among the other regimens. The findings remained consistent within subgroups.

CONCLUSIONS

TMP-SMX is the most effective agent for PCP prophylaxis in PWH and the only agent to confer a mortality benefit; consequently, it should continue to be recommended as the first-line agent. Further studies are necessary to determine the optimal dosing of TMP-SMX to maximize efficacy and minimize toxicity.

Trimethoprim-sulfamethoxazole dosing and outcomes of pulmonary nocardiosis

BACKGROUND

Nocardia often causes pulmonary infection among those with chronic pulmonary disease or immunocompromising conditions. Trimethoprim-sulfamethoxazole (TMP-SMX) is recommended as first-line treatment, though little data exists regarding outcomes of different dosing regimens.

METHODS

We performed a multicenter retrospective cohort study of adult patients with non-disseminated pulmonary nocardiosis initially treated with TMP-SMX monotherapy. Patients' initial TMP-SMX dosing was categorized as high- (> 10 mg/kg/day), intermediate- (5-10 mg/kg/day) or low-dose (< 5 mg/kg/day). Outcomes included one-year mortality, post-treatment recurrence, and dose adjustment or early discontinuation of TMP-SMX. SMX serum concentrations and their effect on management were also assessed. Inverse probability of treatment weighting was applied to Cox regression analyses.

RESULTS

Ninety-one patients were included with 24 (26.4%), 37 (40.7%), and 30 (33.0%) treated with high-, intermediate-, and low-dose TMP-SMX, respectively. Patients who initially received low-dose (HR 0.07, 95% CI 0.01-0.68) and intermediate-dose TMP-SMX (HR 0.27, 95% CI 0.07-1.04) had lower risk of one-year mortality than the high-dose group. Risk of recurrence was similar between groups. Nineteen patients had peak SMX serum concentrations measured which resulted in 7 (36.8%) dose changes and was not associated with one-year mortality or recurrence. However, 66.7% of the high-dose group required TMP-SMX dose adjustment/discontinuation compared to 24.3% of the intermediate-dose and 26.7% of the low-dose groups (p = 0.001).

CONCLUSIONS

Low- and intermediate-dose TMP-SMX for non-disseminated pulmonary nocardiosis were not associated with poor outcomes compared to high-dose therapy, which had a higher rate of dose adjustment/early discontinuation. Historically used high-dose TMP-SMX may not be necessary for management of isolated pulmonary nocardiosis.

Pneumocystis jirovecii Pneumonia in HIV-Negative, Non-transplant Patients: Epidemiology, Clinical Manifestations, Diagnosis, Treatment, and Prevention

Purpose of Review

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic fungal infection that is increasingly seen in HIV-negative patients with immune compromise due to other etiologies. We lack comprehensive clinical recommendations for this population.

Recent Findings

In non-HIV cases, PJP has a mortality rate of up to 50%, which is unacceptable despite the presence of safe and effective prophylaxis and therapy. Steroid use is one of the most common risk factors for disease development. New data suggests that lower doses of the preferred treatment regimen, TMP-SMX, may be equally effective for treatment while limiting side effects. While commonly used, the benefit of corticosteroids for the treatment of PJP has recently been called into question, with a recent multicenter cohort demonstrating no benefit among solid organ transplant recipients.

Summary

A high suspicion of PJP in individuals with pneumonia during immunosuppressant use is crucial. Therapeutic options are evolving to decrease potential side effects while maintaining efficacy in this highly morbid disease.

Pneumocystis jirovecii pneumonia in people living with HIV: a review

Pneumocystis jirovecii is a ubiquitous opportunistic fungus that can cause life-threatening pneumonia. People with HIV (PWH) who have low CD4 counts are one of the populations at the greatest risk of Pneumocystis jirovecii pneumonia (PCP). While guidelines have approached the diagnosis, prophylaxis, and management of PCP, the numerous studies of PCP in PWH are dominated by the 1980s and 1990s. As such, most studies have included younger male populations, despite PCP affecting both sexes and a broad age range. Many studies have been small and observational in nature, with an overall lack of randomized controlled trials. In many jurisdictions, and especially in low- and middle-income countries, the diagnosis can be challenging due to lack of access to advanced and/or invasive diagnostics. Worldwide, most patients will be treated with 21 days of high-dose trimethoprim sulfamethoxazole, although both the dose and the duration are primarily based on historical practice. Whether treatment with a lower dose is as effective and less toxic is gaining interest based on observational studies. Similarly, a 21-day tapering regimen of prednisone is used for patients with more severe disease, yet other doses, other steroids, or shorter durations of treatment with corticosteroids have not been evaluated. Now with the widespread availability of antiretroviral therapy, improved and less invasive PCP diagnostic techniques, and interest in novel treatment strategies, this review consolidates the scientific body of literature on the diagnosis and management of PCP in PWH, as well as identifies areas in need of more study and thoughtfully designed clinical trials.

Low-Dose vs Conventional-Dose Trimethoprim-Sulfamethoxazole Treatment for Pneumocystis Pneumonia in Patients Not Infected With HIV: A Multicenter, Retrospective Observational Cohort Study

BACKGROUND

Trimethoprim-sulfamethoxazole (TMP-SMX) is an effective treatment for Pneumocystis jirovecii pneumonia (PCP) in immunocompromised patients with and without HIV infection; however, a high incidence of adverse events has been observed. Low-dose TMP-SMX is a potentially effective treatment with fewer adverse events; however, evidence is limited.

RESEARCH QUESTION

What is the efficacy and safety of low-dose TMP-SMX for non-HIV PCP compared with conventional-dose TMP-SMX after adjusting for patient background characteristics?

STUDY DESIGN AND METHODS

In this multicenter retrospective cohort study, we included patients diagnosed with non-HIV PCP and treated with TMP-SMX between June 2006 and March 2021 at three institutions. The patients were classified into low-dose (TMP < 12.5 mg/kg/d) and conventional-dose (TMP 12.5-20 mg/kg/d) groups. The primary end point was 30-day mortality, and the secondary end points were 180-day mortality, adverse events grade 3 or higher per the Common Terminology Criteria for Adverse Events v5.0, and initial treatment completion rates. Background characteristics were adjusted using the overlap weighting method with propensity scores.

RESULTS

Fifty-five patients in the low-dose group and 81 in the conventional-dose group were evaluated. In the overall cohort, the average age was 70.7 years, and the proportion of women was 55.1%. The average dose of TMP-SMX was 8.71 mg/kg/d in the low-dose group and 17.78 mg/kg/d in the conventional-dose group. There was no significant difference in 30-day mortality (6.7% vs 18.4%, respectively; P = .080) or 180-day mortality (14.6% vs 26.1%, respectively; P = .141) after adjusting for patient background characteristics. The incidence of adverse events, especially nausea and hyponatremia, was significantly lower in the low-dose group (29.8% vs 59.0%, respectively; P = .005). The initial treatment completion rates were 43.3% and 29.6% in the low-dose and conventional-dose groups (P = .158), respectively.

INTERPRETATION

Survival was similar between the low-dose and conventional-dose TMP-SMX groups, and low-dose TMP-SMX was associated with reduced adverse events in patients with non-HIV PCP.

Pneumocystis jirovecii Pneumonia after Heart Transplantation: Two Case Reports and a Review of the Literature

Post-transplant Pneumocystis jirovecii pneumonia (PcP) is an uncommon but increasingly reported disease among solid organ transplantation (SOT) recipients, associated with significant morbidity and mortality. Although the introduction of PcP prophylaxis has reduced its overall incidence, its prevalence continues to be high, especially during the second year after transplant, the period following prophylaxis discontinuation. We recently described two cases of PcP occurring more than one year after heart transplantation (HT) in patients who were no longer receiving PcP prophylaxis according to the local protocol. In both cases, the disease was diagnosed following the diagnosis of a viral illness, resulting in a significantly increased risk for PcP. While current heart transplantation guidelines recommend Pneumocystis jirovecii prophylaxis for up to 6-12 months after transplantation, after that period they only suggest an extended prophylaxis regimen in high-risk patients. Recent studies have identified several new risk factors that may be linked to an increased risk of PcP infection, including medication regimens and patient characteristics. Similarly, the indication for PcP prophylaxis in non-HIV patients has been expanded in relation to the introduction of new medications and therapeutic regimens for immune-mediated diseases. In our experience, the first patient was successfully treated with non-invasive ventilation, while the second required tracheal intubation, invasive ventilation, and extracorporeal CO2 removal due to severe respiratory failure. The aim of this double case report is to review the current timing of PcP prophylaxis after HT, the specific potential risk factors for PcP after HT, and the determinants of a prompt diagnosis and therapeutic approach in critically ill patients. We will also present a possible proposal for future investigations on indications for long-term prophylaxis.

How to diagnose and treat a non-HIV patient with Pneumocystis jirovecii pneumonia (PCP)?

BACKGROUND

Pneumocystis jirovecii Pneumonia (PCP) incidence is increasing in non-HIV infected patients. In contrast to PCP in patients infected with HIV, diagnosis is often delayed, and illness is associated with an increased mortality.

OBJECTIVE

To provide a comprehensive review of clinical presentation, risk factors, diagnostic strategies, and treatment options of PCP in non-HIV-infected patients.

SOURCES

Web-based literature review on PCP for trials, meta-analyses and systematic reviews using PubMed. Restriction to English language was applied.

CONTENT

Common underlying conditions in non-HIV-infected patients with PCP are haematological malignancies, autoimmune and inflammatory diseases, solid organ or haematopoietic stem cell transplant and prior exposure to corticosteroids. New risk groups include patients receiving monoclonal antibodies and immunomodulating therapies. Non-HIV-infected patients with PCP present with rapid onset and progression of pneumonia, increased duration of hospitalization and a significantly higher mortality rate than patients infected with HIV. PCP is diagnosed by a combination of clinical symptoms, radiological and mycological features. Immunofluorescence microscopy from bronchoalveolar lavage (BAL) or PCR testing CT imaging and evaluation of the clinical presentation are required. The established treatment regime consists of trimethoprim and sulfamethoxazole.

IMPLICATIONS

While the number of patients immunosuppressed for other causes than HIV is increasing, a simultaneous rise in PCP incidence is observed. In the group of non-HIV-infected patients, a rapid onset of symptoms, a more complex course, and a higher mortality rate are recorded. Therefore, time to diagnosis must be as short as possible to initiate effective therapy promptly. This review aims to raise awareness of PCP in an increasingly affected at-risk group and provide clinicians with a practical guide for efficient diagnosis and targeted therapy. Furthermore, it intends to display current inadequacies in research on the topic of PCP.

Population kinetic-pharmacodynamic analysis of serum potassium in patients receiving sulfamethoxazole/trimethoprim

Since trimethoprim (TMP) dose-dependently inhibits the excretion of potassium, a population kinetic-pharmacodynamic analysis was performed to establish an adequate dosing schedule and characterize factors of hyperkalaemia. Dataset was constructed using a retrospective observational cohort of hospitalized patients (>18 years) with oral sulfamethoxazole/trimethoprim formulation. The model integrated a kinetic model for TMP, a urinary TMP concentration-response curve, and a kinetic model for serum potassium using an indirect response model. The model was a function of body weight, renal function, serum potassium levels, and TMP dosing schedule. We evaluated covariates by the stepwise forward and backward selection methods. The Monte Carlo simulation determined the probability of hyperkalaemia (>5.5 meq/L or >6.0 meq/L) according to the dosing schedule, renal function, and covariates. This study included 317 patients (age 62 [42-72] years) with 4359 serum potassium levels. The significant covariate was non-steroidal anti-inflammatory drugs (NSAIDs), with a 72.3% reduction in 50% inhibitory concentration. Monte Carlo simulation revealed that high-dose TMP (400 mg thrice daily) co-administered with NSAIDs led to mild hyperkalaemia (>10%) and severe hyperkalaemia (approximately 5%), regardless of renal function. In conclusion, clinicians should pay attention to hyperkalaemia with TMP high-dose and co-administered NSAIDs.

Exploring the Differences in Pneumocystis Pneumonia Infection Between HIV and Non-HIV Patients

Pneumocystis pneumonia (PCP) is one of the most common opportunistic infections worldwide that affects the lung. Pneumocystis leads to pneumonia, caused by Pneumocystis jirovecii, formerly known as Pneumocystis carinii. In recent decades, PCP has been a major health problem for human immunodeficiency virus (HIV) patients and is responsible for most of mortality and morbidity. However, the increasing number of immunosuppressive-related diseases has led to outbreaks in other patient populations, raising the concern for PCP as it becomes a major concern among those patients. These changes led to marked changes in the prevalence and mortality rates of PCP. Huge variations in those parameters among HIV and non-HIV patients have been seen also. Historically, the diagnosis was made by staining and direct visualization of the organism within the bronchoalveolar lavage (BAL) fluid. The diagnosis is now made by microscopic examination and a real-time polymerase chain reaction (PCR) of BAL. Serum (1,3)-β-D-glucan, which is a component of the Pneumocystis jirovecii cell wall that distinguishes it from other fungi, has become an important diagnostic tool. Early diagnosis and treatment play a vital role in the patient’s survival and in the infection outcome; hence, empirical PCP therapy should be started immediately when the infection is suspected without waiting for the results of the diagnostic test. Steroids play an important role in the treatment of HIV patients, especially patients who present with hypoxia and respiratory failure. Prophylaxis is very effective and should be given to all patients at high risk of PCP. Antiretroviral therapy (ART) should be started as soon as possible in newly diagnosed HIV-infected patients with PCP, and the immune status of immunocompromised patients with PCP should be improved by temporarily withholding immunosuppressive drugs or reducing their doses.

Low-dose trimethoprim-sulfamethoxazole for the treatment of Pneumocystis jirovecii pneumonia (LOW-TMP): protocol for a phase III randomised, placebo-controlled, dose-comparison trial

INTRODUCTION

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic infection of immunocompromised hosts with significant morbidity and mortality. The current standard of care, trimethoprim-sulfamethoxazole (TMP-SMX) at a dose of 15-20 mg/kg/day, is associated with serious adverse drug events (ADE) in 20%-60% of patients. ADEs include hypersensitivity reactions, drug-induced liver injury, cytopenias and renal failure, all of which can be treatment limiting. In a recent meta-analysis of observational studies, reduced dose TMP-SMX for the treatment of PJP was associated with fewer ADEs, without increased mortality.

METHODS AND ANALYSIS

A phase III randomised, placebo-controlled, trial to directly compare the efficacy and safety of low-dose TMP-SMX (10 mg/kg/day of TMP) with the standard of care (15 mg/kg/day of TMP) among patients with PJP, for a composite primary outcome of change of treatment, new mechanical ventilation, or death. The trial will be undertaken at 16 Canadian hospitals. Data will be analysed as intention to treat. Primary and secondary outcomes will be compared using logistic regression adjusting for stratification and presented with 95% CI.

ETHICS AND DISSEMINATION

This study has been conditionally approved by the McGill University Health Centre; Ethics approval will be obtained from all participating centres. Results will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT04851015.

Pathophysiological mechanism of non-HIV Pneumocystis jirovecii pneumonia

While Pneumocystis jirovecii pneumonia (PCP) can occur in immunocompromised patients with HIV infection, the prognosis of non-HIV PCP is still poor, showing a high mortality rate of 30%-75%. The pathophysiological mechanism of non-HIV PCP is quite different from that of HIV-PCP. Aging, underlying disease, dysbiotic gut microbiome, and Th1 predominance, leads to macrophagic polarization shifting from M2 to M1. These cause dysregulation in the host immunity against P. jirovecii, resulting in severe lung injury and a high mortality rate among non-HIV PCP patients. This review describes poor prognostic factors, an issue of predictive values used for general pneumonia practice, and new aspects, including the dysbiosis of the gut microbiome and macrophagic polarization in the treatment of non-HIV PCP.

Treatment With Reduced-Dose Trimethoprim-Sulfamethoxazole Is Effective in Mild to Moderate Pneumocystis jirovecii Pneumonia in Patients With Hematologic Malignancies

BACKGROUND

Recent studies have reported that reduced-dose trimethoprim-sulfamethoxazole (TMP-SMX) may be effective in the treatment of Pneumocystis jirovecii pneumonia (PJP), but data are lacking for patients with hematologic malignancies.

METHODS

This retrospective study included all adult hematologic patients with PJP between 2013 and 2017 at 6 Swedish university hospitals. Treatment with 7.5-15 mg TMP/kg/day (reduced dose) was compared with >15-20 mg TMP/kg/day (standard dose), after correction for renal function. The primary outcome was the change in respiratory function (Δpartial pressure of oxygen [PaO2]/fraction of inspired oxygen [FiO2]) between baseline and day 8. Secondary outcomes were clinical failure and/or death at day 8 and death at day 30.

RESULTS

Of a total of 113 included patients, 80 patients received reduced dose and 33 patients received standard dose. The overall 30-day mortality in the whole cohort was 14%. There were no clinically relevant differences in ΔPaO2/FiO2 at day 8 between the treatment groups, either before or after controlling for potential confounders in an adjusted regression model (-13.6 mm Hg [95% confidence interval {CI}, -56.7 to 29.5 mm Hg] and -9.4 mm Hg [95% CI, -50.5 to 31.7 mm Hg], respectively). Clinical failure and/or death at day 8 and 30-day mortality did not differ significantly between the groups (18% vs 21% and 14% vs 15%, respectively). Among patients with mild to moderate pneumonia, defined as PaO2/FiO2 >200 mm Hg, all 44 patients receiving the reduced dose were alive at day 30.

CONCLUSIONS

In this cohort of 113 patients with hematologic malignancies, reduced-dose TMP-SMX was effective and safe for treating mild to moderate PJP.

Pneumocystis in the era of prophylaxis: do the guidelines have to change?

PURPOSE

In the era of effective prophylaxis, the objective of this study was to describe pneumocystis pneumonia (PCP) patients' profile and evaluate the consistency of clinical situations encountered with the recommended indications for prophylaxis.

METHODS

This was a single-centre, retrospective study. All adults (> 18 years) with a definitive diagnosis of PCP were included. Data were collected from patients' electronic medical files.

RESULTS

The study examined the medical files of 225 patients diagnosed with PCP and treated between 1 January, 2015, and 30 June, 2020. More than 95% of the patients were not on anti-PCP prophylaxis at the time of PCP diagnosis. There were 32 (14%) deaths before the end of PCP treatment, mainly in auto-immune disease (30%) and solid tumours (38%) groups unlike the solid-organ transplants group, among whom deaths were infrequent. Indeed, 48% of our cohort (n = 107) had both corticosteroid (CS) therapy, immunosuppressive or immunomodulatory treatment, and lymphopaenia and could have been considered at high risk for PCP. Trimethoprim/sulfamethoxazole was administered as first-line PCP curative treatment in 95% of the patients. Toxicities of this drug led to treatment interruption in 25% of the patients (except death).

CONCLUSIONS

This study found a high number of PCP cases over 5 years. Unsurprisingly, most of the patients were immunosuppressed, with risk factors for PCP already described in the literature. This large number of PCP cases should be avoidable and, consequently, questions arise. Faced with these data, prophylaxis should be common sense for immunocompromised patients with risk factors, even if formalised recommendations do not exist.

Observational study of the clinical utility of sulfamethoxazole serum level monitoring in the treatment of brain abscesses due to Nocardia species

Although there is a lack of data in trimethoprim-sulfamethoxazole (TMP-SMX) serum monitoring utility for invasive nocardial infections, therapeutic drug monitoring is widely used to optimize dosing and avoid adverse reactions that may cause treatment interruption.We retrospectively reviewed all adults who received TMP-SMX to treat nocardial brain abscess and had SMX serum level testing from 2010 to 2020.Twenty-two patients received treatment with TMP-SMX for Nocardia species brain abscess and 16 (72.7%) had a reported SMX level, with a median patient age of 65.5 years (interquartile range, IQR 59.5-72.5). Compared to those who did not have a documented SMX serum level, patients with SMX levels had a shorter median course of TMP-SMX treatment (322 days [IQR 188-365] vs. 365 [IQR 224-365]; P = .31) and higher therapeutic induction dose (10 [62.5%] vs. 3 [50%]; P = .92). Similarly, they were more frequently on hemodialysis (3 [13.6%] vs. 1 [4.5%]; P = > .99). The median peak level was 158.5 (IQR 120-218) μg/mL, collected at 2 hours (75%) post-administration in the induction phase (81.3%). Patients with documented SMX levels had fewer reported drug toxicity (5 [31.3%] vs. 4 [66.7%]; P = .1) than those without SMX levels. Among the five patients who reported TMP-SMX-related toxicity, 4 (80%) had an SMX peak level >150 μg/mL. There was no difference in the cure, relapse, and death rates among the two groups.While SMX level was not associated with Nocardia species brain abscess cure rates and mortality, most patients with SMX peak >150 μg/mL experienced drug toxicity.

Trimethoprim-Sulfamethoxazole (Bactrim) Dose Optimization in Pneumocystis jirovecii Pneumonia (PCP) Management: A Systematic Review

(1) Background: Pneumocystis jirovecii pneumonia (PCP) has a substantial impact on the morbidity and mortality of patients, especially those with autoimmune disorders, thus requiring optimal dosing strategies of Trimethoprim–Sulfamethoxazole (TMP-SMX). Therefore, to ensure the safety of TMP-SMX, there is a high demand to review current evidence in PCP patients with a focus on dose optimization strategies; (2) Methods: Various databases were searched from January 2000 to December 2021 for articles in English, focusing on the dose optimization of TMP-SMX. The data were collected in a specific form with predefined inclusion and exclusion criteria. The quality of each article was evaluated using a Newcastle–Ottawa Scale (NOS) for retrospective studies, Joanna Briggs Institute (JBI) critical checklist for case reports, and Cochrane bias tool for randomized clinical trials (RCTs); (3) Results: Thirteen studies met the inclusion criteria for final analysis. Of the 13 selected studies, nine were retrospective cohort studies, two case reports, and two randomized controlled trials (RCT). Most of the studies compared the high-dose with low-dose TMP-SMX therapy for PCP. We have found that a low dose of TMP-SMX provides satisfactory outcomes while reducing the mortality rate and PCP-associated adverse events. This strategy reduces the economic burden of illness and enhances patients’ compliance to daily regimen plan; (4) Conclusions: The large-scale RCTs and cohort studies are required to improve dosing strategies to prevent initial occurrence of PCP or to prevent recurrence of PCP in immune compromised patients.

The effectiveness and safety of low dose trimethoprim-sulfamethoxazole for the treatment of pneumocystis pneumonia: A systematic review and meta-analysis

BACKGROUND

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic fungal infection causing significant morbidity and mortality in immunocompromised patients. The conventional treatment of PJP is sulfamethoxazole-trimethoprim (SMX-TMP) dosed at 15-20 mg/kg/day of the trimethoprim component. Several studies have suggested similar mortality outcomes and an improved adverse effect profile using a lower dose (<15 mg/kg/day) SMX-TMP regimen. Our objective of this meta-analysis was to evaluate the safety and efficacy of lower dose SMX-TMP for PJP pneumonia.

METHODS

We conducted a systematic review and meta-analysis of the existing literature according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. MEDLINE and Embase databases were searched from inception to January 15, 2020, for studies in English evaluating low-dose SMX-TMP (<15 mg/kg/day) compared to conventional dosing for the treatment of PJP. Outcomes evaluated in our meta-analysis include survival and adverse reactions.

RESULTS

After excluding studies that did not meet our inclusion criteria, four studies were analyzed for adverse reactions and three for mortality. Overall, there was no significant difference in mortality between low-dose and conventional-dose SMX-TMP groups (relative risk [RR]: 0.55, 95% confidence interval [CI], 0.18-1.70). There was a significant decrease in the rate of adverse reactions for the low-dose group compared with the conventional-dose group (RR: 0.70, 95% CI, 0.53-0.91).

CONCLUSIONS

This meta-analysis shows a significant decrease in adverse reactions and similar mortality rates with lower-dose SMX-TMP compared to conventional dosing. A low-dose SMX-TMP regimen in the treatment of PJP should be considered a viable option as it could potentially decrease treatment discontinuation rates and reduce patient harm.

Non-invasive diagnosis of Pneumocystis jirovecii pneumonia: a systematic review and meta-analysis

BACKGROUND

Pneumocystis jirovecii pneumonia (PCP) is an opportunistic infection commonly affecting immunocompromised people. Diagnosis usually requires invasive techniques to obtain respiratory specimens. Minimally invasive detection tests have been proposed, but their operating characteristics are poorly described.

OBJECTIVES

To systematically review and meta-analyse the performance of minimally invasive PCP detection tests to inform diagnostic algorithms.

DATA SOURCES

Medline, Embase, Cochrane Library (inception to 15 October 2020).

STUDY ELIGIBILITY CRITERIA

Studies of minimally invasive PCP detection tests were included if they contained a minimum of ten PCP cases.

PARTICIPANTS

Adults at risk of PCP.

TESTS

Non-invasive PCP detection tests.

REFERENCE STANDARD

Diagnosis using the combination of clinical and radiographical features with invasive sampling.

ASSESSMENT OF RISK BIAS

Using the QUADAS-2 tool.

METHODS

We used bivariate and, when necessary, univariate analysis models to estimate diagnostic test sensitivity and specificity.

RESULTS

Fifty-two studies were included; most studies (40) comprised exclusively human immunodeficiency virus (HIV) -infected individuals; nine were mixed (HIV and non-HIV), two were non-HIV and one study did not report HIV status. Sampling sites included induced sputum, nasopharyngeal aspirate, oral wash and blood. The four testing modalities evaluated were cytological staining, fluorescent antibody, PCR and lactate dehydrogenase. Induced sputum had the most data available; this modality was both highly sensitive at 99% (95% CI 51%-100%) and specific at 96% (95% CI 88%-99%). Induced sputum cytological staining had moderate sensitivity at 50% (95% CI 39%-61%) and high specificity at 100% (95% CI 100%-100%), as did fluorescent antibody testing with sensitivity 74% (95% CI 62%-87%) and specificity 100% (95% CI 91%-100%).

CONCLUSION

There are several promising minimally invasive PCP diagnostic tests available, some of which may reduce the need for invasive respiratory sampling. Understanding the operating characteristics of these tests can augment current diagnostic strategies and help establish a more confident clinical diagnosis of PCP. Further studies in non-HIV infected populations are needed.

Safety and efficacy evaluation of low-dose trimethoprim-sulfamethoxazole for prophylaxis of Pneumocystis pneumonia in HIV uninfected patients undergoing hemodialysis: a retrospective observational study

BACKGROUND

Pneumocystis pneumonia (PCP) is a potentially life-threatening infection. Trimethoprim-sulfamethoxazole (TMP-SMX) is considered as the first regimen for PCP prophylaxis according to several guidelines. The recommended prophylactic dose of TMP-SMX has been determined based on patients with normal renal function, but the appropriate dosage for patients undergoing hemodialysis is unknown. The aim of this study was to investigate the efficacy and safety of low-dose TMP-SMX in patients undergoing hemodialysis.

METHODS

HIV-uninfected adult patients who were undergoing hemodialysis and administered TMP-SMX for PCP prophylaxis, were included, and divided into standard-dose (≥6 single strength (SS, TMP-SMX 80 mg/400 mg tablets/week) and low-dose groups (< 6 SS tablets/week). The endpoints were cumulative incidence of PCP and cumulative discontinuation rate of TMP-SMX due to adverse events. For comparison of the groups, we employed the chi-squared test for categorical variables and the Mann-Whitney U test for continuous variables. Risk factors for the endpoints were evaluated using the Cox Fine and Gray method.

RESULTS

The median age of the 81 patients included in the study was 67 years (IQR: 60-76 years), and 52 patients (64.2%) were men. No patients in either group developed PCP during the observation period. The yearly cumulative incidence of discontinuation was 12.1% (95% confidence interval [CI]: 0.027-0.29) in the low-dose group and 35.6% (95% CI: 0.20-0.52) in the standard-dose group (P = 0.019). The adjusted hazard ratio of the low-dose group compared to standard-dose group was 0.18 (95% CI: 0.04-0.86, P = 0.032).

CONCLUSIONS

None of the study patients developed PCP, and the cumulative discontinuation rate of TMP-SMX due to adverse events was significantly lower in the low-dose group compared to that in the standard-dose group (P = 0.032). These results indicate that low-dose TMP-SMX is an appropriate regimen to maintain a balance between PCP prophylaxis and prevention of adverse events due to TMP-SMX administration. These findings can guide health care professionals to determine TMP-SMX dosage when considering PCP prophylaxis for patients undergoing hemodialysis.