Role of cerebrospinal fluid adenosine deaminase measurement in the diagnosis of tuberculous meningitis: an updated systematic review and meta-analysis.

INTRODUCTION: Tuberculous meningitis (TBM) can be difficult to diagnose. Elevated cerebrospinal fluid (CSF) adenosine deaminase (ADA) is often seen in TBM, but its reliability has been questioned. A previous meta-analysis in 2017 had demonstrated the diagnostic utility of CSF ADA in TBM versus non-TBM. We sought to update this meta-analysis with more recent studies, to determine whether CSF ADA could be used to aid in the early recognition of TBM. METHODS: Electronic searches were performed in PubMed and Scopus on studies published from 2016 to 2022. Ten additional studies were identified and added to 20 studies (from 2000 to 2016) from a previous meta-analysis. Meta-analysis was conducted using the random effects method, estimating the pooled diagnostic odds ratio (DOR) for elevated CSF ADA in the diagnosis of TBM. RESULTS: Of the 30 studies included, 16/30 (53.3%) used the Giusti method for measuring ADA. Fourteen (46.7%) studies used an ADA cut-off of 10 IU/L, and 11 (36.7%) studies used an even lower cut-off. The pooled DOR for elevated CSF ADA in the diagnosis of TBM was 45.40 (95% confidence interval [CI] 31.96-64.47, I2 = 44%). When only studies using the Giusti method were considered, DOR was 44.21 (95% CI 28.37-68.91, I2 = 40%). Among the studies that used a cut-off of 10 IU/L, DOR was 58.09 (95% CI 33.76-99.94, I2 = 41%). CONCLUSION: Studies remain heterogeneous but demonstrate that CSF ADA can differentiate TBM from non-TBM. In line with most studies, CSF ADA >10 IU/L supports the diagnosis of TBM in a patient with compatible symptoms and high-risk epidemiology.

Adding Hyponatremia to the "Rule-of-6" Prediction Tool Improves Performance in Identifying Hospitalised Patients with COVID-19 at Risk of Adverse Clinical Outcomes.

The 'rule-of-6' prediction tool was shown to be able to identify COVID-19 patients at risk of adverse outcomes. During the pandemic, we frequently observed hyponatremia at presentation. We sought to evaluate if adding hyponatremia at presentation could improve the 'rule-of-6' prediction tool. We retrospectively analysed 1781 consecutive patients admitted to a single tertiary academic institution in Singapore with COVID-19 infection from February 2020 to October 2021. A total of 161 (9.0%) patients had hyponatremia. These patients were significantly older, with more co-morbidities and more likely to be admitted during the Delta wave (2021). They were more likely to have radiographic evidence of pneumonia (46.0% versus 13.0%, p < 0.001) and more adverse outcomes (25.5% vs. 4.1%, p < 0.001). Hyponatremia remained independently associated with adverse outcomes after adjusting for age, lack of medical co-morbidities, vaccination status, year of admission, CRP, LDH, and ferritin. The optimised cut-off for serum sodium in predicting adverse outcomes was approximately <135 mmol/L as determined by the Youden index. Although derived in early 2020, the 'rule-of-6' prediction tool continued to perform well in our later cohort (AUC: 0.72, 95%CI: 0.66-0.78). Adding hyponatremia to the 'rule-of-6' improved its performance (AUC: 0.76, 95%CI: 0.71-0.82). Patients with hyponatremia at presentation for COVID-19 had poorer outcomes even as new variants emerged.

Trends in electrocardiographic and cardiovascular manifestations of patients hospitalised with COVID-19.

INTRODUCTION: Early in the coronavirus disease 2019 (COVID-19) pandemic, a low incidence of cardiovascular complications was reported in Singapore. Little was known about the trend of cardiovascular complications as the pandemic progressed. In this study, we examined the evolving trends in electrocardiographic and cardiovascular manifestations in patients hospitalised with COVID-19. METHODS: We examined the first 1781 consecutive hospitalised patients with polymerase chain reaction-confirmed COVID-19. We divided the population based on whether they had abnormal heart rate (HR) or electrocardiography (ECG) or normal HR and ECG, comparing the baseline characteristics and outcomes. Cardiovascular complications were defined as acute myocardial infarction, stroke, pulmonary embolism, myocarditis and mortality. RESULTS: The 253 (14.2%) patients who had abnormal HR/ECG at presentation were more likely to be symptomatic. Sinus tachycardia was commonly observed. Troponin I levels (97.0 ± 482.9 vs. 19.7 ± 68.4 ng/L, P = 0.047) and C-reactive protein levels (20.1 ± 50.7 vs. 13.9 ± 24.1 µmol/L, P = 0.003) were significantly higher among those with abnormal HR/ECGs, with a higher prevalence of myocarditis (2.0% vs. 0.5%, P = 0.019), pulmonary embolism (2.0% vs. 0.3%, P = 0.008) and acute myocardial infarction (1.2% vs. 0.1%, P = 0.023). After adjusting for age and comorbidities, abnormal HR/ECG (adjusted odds ratio 4.41, 95% confidence interval 2.21-8.77; P < 0.001) remained independently associated with adverse cardiovascular complications. Over time, there was a trend towards a higher proportion of hospitalised patients with cardiovascular complications. CONCLUSION: Cardiovascular complications appear to be increasing in proportion over time among hospitalised patients with COVID-19. A baseline ECG and HR measurement may be helpful for predicting these complications.

ChatGPT as a tool to improve access to knowledge on sexually transmitted infections.

OBJECTIVES: Specific to sexual health, individuals in need of information may be adolescents who have limited ability to formally access healthcare. These digital natives may turn to ChatGPT to address their concerns on sexually transmitted infections (STI). We sought to evaluate the veracity of ChatGPT's responses to commonly asked questions on STIs. METHODS: We instructed ChatGPT (GPT 3.5) to answer STI questions from three domains, namely, (1) general risk factors for STIs, (2) access to care and diagnosis of STIs and (3) management of STIs and postexposure prophylaxis. The responses were recorded and checked against the US Centers for Disease Control and Prevention STI Treatment Guidelines 2021. RESULTS: Overall, the responses were concise and accurate. In terms of prevention, ChatGPT could also recommend measures like safe sex practices and human papillomavirus vaccination. However, it failed to recommend HIV pre-exposure prophylaxis. When an individual expressed a symptom that could potentially represent STI (eg, dyspareunia) ChatGPT appropriately provided reassurance that other possibilities exist, but advocated for testing. In terms of treatment, ChatGPT consistently communicated the importance of partner testing and follow-up testing, but at times, failed to highlight the importance of testing for other STIs. Overall, the advice given was not tailored to the specific individual's circumstances. CONCLUSIONS: ChatGPT can provide helpful information regarding STIs, but the advice lacks specificity and requires a human physician to fine-tune. Its ubiquity may make it a useful adjunct to sexual health clinics, to improve knowledge and access to care.

Infectious etiologies of persistent and chronic diarrhea in Asian developing countries: A systematic review and meta-analysis.

Infectious causes of diarrhea contribute significantly to morbidity in Asia. We conducted a systematic review and meta-analysis of the prevalence of infectious etiologies of persistent and chronic diarrhea in Asian adults. Searches were performed on PubMed and Scopus for studies from January 1, 1970, to May 30, 2023. Sixteen studies were identified and included. The meta-analysis was conducted with the random-effects method, estimating the pooled prevalence of groups of infectious pathogens as causes of persistent and chronic diarrhea among Asian adults. The findings were highly heterogeneous and indicative of publication bias. The majority of studies were conducted on persons living with human immunodeficiency virus infection (PLHIV). The studies were predominantly from low-income and middle-income Asian countries. The most common cause was parasitic, with a pooled prevalence of 0.52 (95% confidence interval 0.28-0.65, I2 = 99%, Cochran's Q = 1027.44, P < 0.01), followed by bacterial, fungal, and viral causes, which were substantially rarer. Negative microbiological testing was also common, with a pooled prevalence for a negative test being 0.37 (95% confidence interval 0.17-0.52, I2 = 99%, Cochran's Q = 1027.44, P < 0.01). Subgroup analyses of studies conducted among PLHIV, from year 2000 and among those conducted in Southeast Asia showed a similar prevalence of parasitic causes of diarrhea. In conclusion, in Asian adults with persistent and chronic diarrhea, parasitic causes were most prevalent. However, the estimate of true prevalence is limited by significant heterogeneity among the available studies. More study in this field is required, especially examining PLHIV in the post-antiretroviral therapy era and from high-income countries.

Elevated serum lactate dehydrogenase aids prediction of mortality in Pneumocystis jirovecii pneumonia without underlying human immunodeficiency virus infection - Derivation of a clinical risk score.

Pneumocystis jirovecii pneumonia (PCP) is associated with significant mortality amongst patients without underlying human immunodeficiency virus infection (HIV). We sought to develop a risk score to predict mortality in this population. We reviewed patients with a presumed or confirmed PCP and a negative HIV test from 2006-2023. We constructed a multivariable model to identify parameters independently associated with mortality and the adjusted odds ratios were converted to weights to derive a risk score. Subsequently, we compared the performance of our score to the CURB-65 score by means of area under receiver operating characteristic curve (AUC). In total, we examined 93 patients with PCP without HIV. Mortality was 31.2%. Risk factors for mortality included older age, male sex and high serum lactate dehydrogenase levels (LDH) and C-reactive protein levels. A risk score was derived comprising age> 65 years (2 points), male sex (2 points) and LDH> 770 U/L (3 points). Our risk score (AUC 0.71, 95%CI 0.60-0.82) performed better than the CURB-65 score (AUC 0.53, 95%CI 0.41-0.66). A low-risk score of 0-1 had excellent negative predictive value for mortality (97.5%). In conclusion, a risk score comprising age, sex and LDH can predict mortality in PCP without underlying HIV and help with prognostication.

Performance of Risk Scores in Predicting Infective Endocarditis in Patients with Staphylococcus aureus Bacteraemia in a Prospective Asian Cohort.

Background: Several risk scores have been derived to predict the risk of infective endocarditis (IE) amongst patients with Staphylococcus aureus bacteraemia (SAB), which helps to guide clinical management. Methods: We prospectively studied 634 patients admitted with SAB. The cohort was stratified into those with or without IE, and the PREDICT Day 1, Day 5 and VIRSTA scores were tabulated. Area under the receiver operating characteristic (AUC) curves were constructed to compare the performance of each score. Results: Of the 634 patients examined, 36 (5.7%) had IE. These patients were younger (51.6 ± 20.1 vs. 59.2 ± 18.0 years, p = 0.015), tended to have community acquisition of bacteraemia (41.7% vs. 17.9%, p < 0.001), and had persistent bacteraemia beyond 72 h (19.4% vs. 6.0%, p = 0.002). The VIRSTA score had the best performance in predicting IE (AUC 0.76, 95%CI 0.66-0.86) compared with PREDICT Day 1 and Day 5. A VIRSTA score of <3 had the best negative predictive value (97.5%), compared with PREDICT Day 1 (<4) and Day 5 (<2) (94.3% and 96.6%, respectively). Conclusions: Overall, the risk scores performed well in our Asian cohort. If applied, 23.5% of the cohort with a VIRSTA ≥ 3 would require TEE, and a score of <3 had an excellent negative predictive value.

The role of an artificial intelligence model in antiretroviral therapy counselling and advice for people living with HIV.

OBJECTIVES: People living with HIV may find personalized access to accurate information on antiretroviral therapy (ART) challenging given the stigma and costs potentially associated with attending physical consultations. Artificial intelligence (AI) chatbots such as ChatGPT may help to lower barriers to accessing information addressing concerns around ART initiation. However, the safety and accuracy of the information provided remains to be studied. METHODS: We instructed ChatGPT to answer questions that people living with HIV frequently ask about ART, covering i) knowledge of and access to ART; ii) ART initiation, side effects, and adherence, and iii) general sexual health practices while receiving ART. We checked the accuracy of the advice against international HIV clinical practice guidelines. RESULTS: ChatGPT answered all questions accurately and comprehensively. It recognized potentially life-threatening scenarios such as abacavir hypersensitivity reaction and gave appropriate advice. However, in certain contexts, such as specific geographic locations or for pregnant individuals, the advice lacked specificity to an individual's unique circumstances and may be inadequate. Nevertheless, ChatGPT consistently re-directed the individual to seek help from a healthcare professional to obtain targeted advice. CONCLUSIONS: ChatGPT may act as a useful adjunct in the process of ART counselling for people living with HIV. Improving access to information on and knowledge about ART may improve access and adherence to ART and outcomes for people living with HIV overall.

Study protocol: infectious diseases consortium (I3D) for study on integrated and innovative approaches for management of respiratory infections: respiratory infections research and outcome study (RESPIRO).

BACKGROUND: Community-acquired respiratory infections are a leading cause of illness and death globally. The aetiologies of community-acquired pneumonia remain poorly defined. The RESPIRO study is an ongoing prospective observational cohort study aimed at developing pragmatic logistical and analytic platforms to accurately identify the causes of moderate-to-severe community-acquired pneumonia in adults and understand the factors influencing disease caused by individual pathogens. The study is currently underway in Singapore and has plans for expansion into the broader region. METHODS: RESPIRO is being conducted at three major tertiary hospitals in Singapore. Adults hospitalised with acute community-acquired pneumonia or lower respiratory tract infections, based on established clinical, laboratory and radiological criteria, will be recruited. Over the course of the illness, clinical data and biological samples will be collected longitudinally and stored in a biorepository for future analysis. DISCUSSION: The RESPIRO study is designed to be hypothesis generating, complementary to and easily integrated with other research projects and clinical trials. The detailed clinical database and biorepository will yield insights into the epidemiology and outcomes of community-acquired lower respiratory tract infections in Singapore and the surrounding region and offers the opportunity to deeply characterise the microbiology and immunopathology of community-acquired pneumonia.

Individualised, short-course antibiotic treatment versus usual long-course treatment for ventilator-associated pneumonia (REGARD-VAP): a multicentre, individually randomised, open-label, non-inferiority trial.

BACKGROUND: Ventilator-associated pneumonia (VAP) is associated with increased mortality, prolonged hospitalisation, excessive antibiotic use and, consequently, increased antimicrobial resistance. In this phase 4, randomised trial, we aimed to establish whether a pragmatic, individualised, short-course antibiotic treatment strategy for VAP was non-inferior to usual care. METHODS: We did an individually randomised, open-label, hierarchical non-inferiority-superiority trial in 39 intensive care units in six hospitals in Nepal, Singapore, and Thailand. We enrolled adults (age ≥18 years) who met the US Centers for Disease Control and Prevention National Healthcare Safety Network criteria for VAP, had been mechanically ventilated for 48 h or longer, and were administered culture-directed antibiotics. In culture-negative cases, empirical antibiotic choices were made depending on local hospital antibiograms reported by the respective microbiology laboratories or prevailing local guidelines. Participants were assessed until fever resolution for 48 h and haemodynamic stability, then randomly assigned (1:1) to individualised short-course treatment (≤7 days and as short as 3-5 days) or usual care (≥8 days, with precise durations determined by the primary clinicians) via permuted blocks of variable sizes (8, 10, and 12), stratified by study site. Independent assessors for recurrent pneumonia and participants were masked to treatment allocation, but clinicians were not. The primary outcome was a 60-day composite endpoint of death or pneumonia recurrence. The non-inferiority margin was prespecified at 12% and had to be met by analyses based on both intention-to-treat (all study participants who were randomised) and per-protocol populations (all randomised study participants who fulfilled the eligibility criteria, met fitness criteria for antibiotic discontinuation, and who received antibiotics for the duration specified by their allocation group). This study is registered with ClinicalTrials.gov, number NCT03382548. FINDINGS: Between May 25, 2018, and Dec 16, 2022, 461 patients were enrolled and randomly assigned to the short-course treatment group (n=232) or the usual care group (n=229). Median age was 64 years (IQR 51-74) and 181 (39%) participants were female. 460 were included in the intention-to-treat analysis after excluding one withdrawal (231 in the short-course group and 229 in the usual care group); 435 participants received the allocated treatment and fulfilled eligibility criteria, and were included in the per-protocol population. Median antibiotic treatment duration for the index episodes of VAP was 6 days (IQR 5-7) in the short-course group and 14 days (10-21) in the usual care group. 95 (41%) of 231 participants in the short-course group met the primary outcome, compared with 100 (44%) of 229 in the usual care group (risk difference -3% [one-sided 95% CI -∞ to 5%]). Results were similar in the per-protocol population. Non-inferiority of short-course antibiotic treatment was met in the analyses, although superiority compared with usual care was not established. In the per-protocol population, antibiotic side-effects occurred in 86 (38%) of 224 in the usual care group and 17 (8%) of 211 in the short-course group (risk difference -31% [95% CI -37 to -25%; p<0·0001]). INTERPRETATION: In this study of adults with VAP, individualised shortened antibiotic duration guided by clinical response was non-inferior to longer treatment durations in terms of 60-day mortality and pneumonia recurrence, and associated with substantially reduced antibiotic use and side-effects. Individualised, short-course antibiotic treatment for VAP could help to reduce the burden of side-effects and the risk of antibiotic resistance in high-resource and resource-limited settings. FUNDING: UK Medical Research Council; Singapore National Medical Research Council. TRANSLATIONS: For the Thai and Nepali translations of the abstract see Supplementary Materials section.

Biomarkers of early SARS-CoV-2 infection before the onset of respiratory symptoms.

OBJECTIVES: Currently, limited data exist regarding the pathological changes occurring during the incubation phase of SARS-CoV-2 infection. We utilized proteomic analysis to explore changes in the circulatory host response in individuals with SARS-CoV-2 infection before the onset of symptoms. METHODS: Participants were individuals from a randomized clinical trial of prophylaxis for COVID-19 in a workers' dormitory. Proteomic signatures of blood samples collected within 7 days before symptom onset (incubation group) were compared with those collected >21 days (non-incubation group) to derive candidate biomarkers of incubation. Candidate biomarkers were assessed by comparing levels in the incubation group with both infected individuals (positive controls) and non-infected individuals (negative controls). RESULTS: The study included men (mean age 34.2 years and standard deviation 7.1) who were divided into three groups: an incubation group consisting of 44 men, and two control groups-positive (n = 56) and negative (n = 67) controls. Through proteomic analysis, we identified 49 proteins that, upon pathway analyses, indicated an upregulation of the renin-angiotensin and innate immune systems during the virus incubation period. Biomarker analyses revealed increased concentrations of plasma angiotensin II (mean 731 vs. 139 pg/mL), angiotensin (1-7) (302 vs. 9 pg/mL), CXCL10 (423 vs. 85 pg/mL), CXCL11 (82.7 vs. 32.1 pg/mL), interferon-gamma (0.49 vs. 0.20 pg/mL), legumain (914 vs. 743 pg/mL), galectin-9 (1443 vs. 836 pg/mL), and tumour necrosis factor (20.3 vs. 17.0 pg/mL) during virus incubation compared with non-infected controls (all p < 0.05). Plasma angiotensin (1-7) exhibited a significant increase before the onset of symptoms when compared with uninfected controls (area under the curve 0.99, sensitivity 0.97, and specificity 0.99). DISCUSSION: Angiotensin (1-7) could play a crucial role in the progression of symptomatic COVID-19 infection, and its assessment could help identify individuals who would benefit from enhanced monitoring and early antiviral intervention.

Predictors of disease severity in SARS-CoV-2 omicron variant XBB sublineages and variants of interest.

The Omicron variant has been reported to present with milder disease compared with Delta, although this may be due to immunity from vaccination and prior exposure. Predictors of severity with recent strains have not been well characterized. We retrospectively examined consecutive cases of moderate-to-severe COVID-19 (defined as requiring supplemental oxygenation, intensive care or mortality) admitted to seven tertiary hospitals across Singapore in April 2023. Whole genome sequencing was performed on each isolate to determine the sublineage, while baseline clinical, laboratory data and outcomes were tabulated. We reviewed 182 patients with moderate-to-severe illness and 466 controls hospitalized at the same time. Advanced age and presence of chronic kidney disease predicted adverse outcome. Previously reported markers such as radiographic evidence of pneumonia, elevated C-reactive protein and serum creatinine levels at presentation also correlated with adverse outcomes. There were no observable differences in outcomes with any specific Omicron XBB sublineage. We did not find any specific Omicron XBB sublineage that was associated with worse outcomes. Larger multinational studies would be important to track the clinical evolution of the virus in its current endemic state.

Antibiotic treatment failure of uncomplicated urinary tract infections in primary care.

BACKGROUND: Higher resistance rates of > 20% have been noted in Enterobacteriaceae urinary isolates towards ciprofloxacin and co-trimoxazole (C + C) in Singapore, compared with amoxicillin-clavulanate and nitrofurantoin (AC + N). This study examined if treatment failure varied between different antibiotics, given different resistant rates, for uncomplicated urinary tract infections (UTIs) managed in primary care. We also aimed to identify gaps for improvement in diagnosis, investigations, and management. METHODS: A retrospective cohort study was conducted from 2019 to 2021 on female patients aged 18-50 with uncomplicated UTIs at 6 primary care clinics in Singapore. ORENUC classification was used to exclude complicated UTIs. Patients with uncomplicated UTIs empirically treated with amoxicillin-clavulanate, nitrofurantoin, ciprofloxacin or co-trimoxazole were followed-up for 28 days. Treatment failure was defined as re-attendance for symptoms and antibiotic re-prescription, or hospitalisation for UTI complications. After 2:1 propensity score matching in each group, modified Poisson regression and Cox proportional hazard regression accounting for matched data were used to determine risk and time to treatment failure. RESULTS: 3194 of 4253 (75.1%) UTIs seen were uncomplicated, of which only 26% were diagnosed clinically. Urine cultures were conducted for 1094 (34.3%) uncomplicated UTIs, of which only 410 (37.5%) had bacterial growth. The most common organism found to cause uncomplicated UTIs was Escherichia coli (64.6%), with 92.6% and 99.4% of isolates sensitive to amoxicillin-clavulanate and nitrofurantoin respectively. Treatment failure occurred in 146 patients (4.57%). Among 1894 patients treated with AC + N matched to 947 patients treated with C + C, patients treated with C + C were 50% more likely to fail treatment (RR 1.49, 95% CI 1.10-2.01), with significantly higher risk of experiencing shorter time to failure (HR 1.61, 95% CI 1.12-2.33), compared to patients treated with AC + N. CONCLUSION: Treatment failure rate was lower for antibiotics with lower reported resistance rates (AC + N). We recommend treating uncomplicated UTIs in Singapore with amoxicillin-clavulanate or nitrofurantoin, based on current local antibiograms. Diagnosis, investigations and management of UTIs remained sub-optimal. Future studies should be based on updating antibiograms, highlighting its importance in guideline development.

Inflammatory phenotypes may be more important than age and comorbidities in predicting clinical outcomes in hospitalised patients with COVID-19.

Objectives: In critically ill patients with COVID-19, distinct hyperinflammatory and hypoinflammatory phenotypes have been described, with different outcomes and responses to therapy. We investigated if similar phenotypes exist in non-severe illness. Methods: Consecutive patients with polymerase chain reaction (PCR) confirmed SARS-CoV-2 were examined. Baseline demographics and laboratory investigations were tabulated, including serum C-reactive protein. Patients were divided into those who were hyperinflammatory (defined as C-reactive protein >17 mg/l) or hypoinflammatory. Adverse outcomes, defined as requiring oxygenation, intensive care, or death, were recorded during the hospital stay. Clinical characteristics and outcomes were compared. Results: Of the 1781 patients examined, 276 (15.5%) had a hyperinflammatory phenotype. They were older (51.8 ± 17.2 vs 40.3 ± 13.8 years, P <0.001), had a lower PCR cycle threshold (PCR cycle threshold value 19.3 ± 6.3 vs 22.7 ± 15.4, P = 0.025) at presentation, and more medical comorbidities. The hyperinflammatory phenotype was independently associated with adverse clinical outcomes, even after adjusting for age, medical history and viral load on multivariable analyses (adjusted odds ratio 5.78, 95% confidence interval 2.86-11.63). Conclusion: Even in non-severe COVID-19, there are distinct hyper- and hypoinflammatory phenotypes, with the hyperinflammatory phenotype strongly associated with adverse clinical outcomes, that could be distinguished with a simple biomarker.