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.

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.

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.

Clinical and echocardiographic characteristics associated with the development of infective endocarditis in patients with significant mitral stenosis.

BACKGROUND: Infective endocarditis (IE) confers significant mortality and morbidity in patients with underlying mitral stenosis (MS), with both diseased native valves and after valvular procedures. PURPOSE: We examined the clinical and echocardiographic parameters in association with the development of IE on patients with significant MS. METHODS: A total of 478 consecutive patients with index echocardiographic diagnosis of significant mitral stenosis (mitral valve area <1.5 cm2 ) were included. Patients were grouped into those with or without IE on at least 5 years of follow-up. Baseline clinical, echocardiographic profile and clinical outcomes were compared. RESULTS: IE was observed in 4.4% (n = 21) of the cohort. These patients were younger (45.3 ± 14.6 vs. 53.2 ± 15.5 years, p = 0.022) at the time of MS diagnosis. NT-proBNP was higher in patients who developed IE (13529 ± 12230 vs. 4381 ± 5875 pg/ml, p < 0.001), with larger left atrial diameter (54.4 ± 10.1 vs. 49.9 ± 9.5 mm, p = 0.040) and elevated pulmonary artery systolic pressure (PASP, 62.3 ± 17.2 vs. 47.2 ± 16.5 mmHg, p = 0.026). There was no significant difference in terms of MS severity, other concomitant valvulopathies, or etiology (rheumatic or degenerative) of MS. Patients who smoked had higher incidence of IE (33.3% vs. 14.2%, log-rank 7.27, p = 0.007). After adjusting for age, valve procedure and PASP, patients who smoked remained at elevated risk of IE (adjusted hazards ratio 2.99, 95% confidence interval 1.18-7.56, p = 0.021). CONCLUSION: IE occurs in a proportion of patients with MS. Smoking, younger age of diagnosis of MS as well as dilated left atria with elevated PASP may be associated with an elevated risk of this complication.

An Asian Perspective on Gender Differences in In-Hospital and Long-Term Outcome of Cardiac Mortality and Ischemic Stroke after Primary Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction.

OBJECTIVES: Gender differences historically exist in cardiovascular disease, with women experiencing higher rates of major adverse cardiovascular events. We investigated these trends in a contemporary Asian cohort, examining the impact of gender differences on cardiac mortality and ischemic stroke after primary percutaneous coronary intervention (PPCI) for ST elevation myocardial infarction (STEMI). MATERIALS AND METHODS: We analysed 3971 consecutive patients who underwent primary PCI for STEMI retrospectively. The primary outcome was cardiac mortality and ischemic stroke in-hospital, at one year and on longer-term follow up (median follow up 3.62 years, interquartile range 1.03-6.03 years). RESULTS: There were 580 (14.6%) female patients and 3391 (85.4%) male patients. Female patients were older and had higher prevalence of hypertension, diabetes, previous strokes, and chronic kidney disease. Cardiac mortality was higher in female patients during in-hospital (15.5% vs. 6.2%), 1-year (17.4% vs. 7.0%) and longer term follow up (19.9% vs. 8.1%, log-rank test: p < 0.001). Similarly, females had higher incidence of ischemic stroke at in-hospital (2.6% vs. 1.0%), 1-year (3.6% vs. 1.4%) and in the longer-term (6.7% vs. 3.1%) as well (log-rank test: p < 0.001). Female gender remained an independent predictor of in-hospital cardiac mortality (HR 1.395, 95%CI 1.061-1.833, p=0.017) and on longer-term follow-up (HR 1.932 95%CI 1.212-3.080, p=0.006) even after adjusting for confounders. CONCLUSIONS: Females were at higher risk of in-hospital and long-term cardiac mortality and ischemic stroke after PPCI for STEMI. Future studies are warranted to investigate the role of aggressive management of cardiovascular risk factors and follow-up to improve outcomes in the females with STEMI.

Inter-Ethnic Differences in Valvular Dysfunction, Aortopathy, and Progression of Disease of an Asian Bicuspid Aortic Valve Population.

BACKGROUND: There are differences in bicuspid aortic valve (BAV) characteristics between Asian and European populations, but little is known about the inter-ethnic differences in bicuspid valve function and aortic root dimensions within the diverse Asian population. METHODS: From 1992-2017, 562 patients with index echocardiographic diagnosis of BAV in a tertiary health care institution in Singapore were analysed according to their ethnic groups: Chinese, Malay, Indian, and Eurasian. Study outcomes included BAV complications (infective endocarditis, aortic dissection) and clinical outcomes (aortic valve surgery, aortic root surgery, all-cause mortality). Total events were defined as composite outcome of all BAV complications and outcomes. Aortic dimensions and aortic dilatation rates were also studied. RESULTS: There were 379 (67.5%) Chinese, 79 (14.0%) Malay, 73 (13.0%) Indian, and 31 (5.5%) Eurasian patients. Type 1 BAV (58.5%) was the most prevalent BAV morphology, with moderate-to-severe aortic stenosis (AS) (36.8%) being the most common complication in the overall population. There was a higher prevalence of type 0 BAV in Chinese and Indian groups, and type 1 BAV with fusion of left-right coronary cusp in Eurasian and Malay groups (p=0.082). There was no difference in significant AS among groups. The highest prevalence of moderate-to-severe aortic regurgitation was observed amongst the Eurasian group, followed by Chinese, Indian, and Malay groups (p=0.033). The Chinese group had the largest mean indexed diameters of the aortic root. Multivariable linear regression demonstrated that only the Chinese had significantly larger indexed diameters in the aortic annulus, sinotubular junction (STJ), and ascending aorta (AA), relative to the Eurasian group, after adjusting for age, sex, smoking, hypertension, hyperlipidaemia, diabetes, and aortic regurgitation. On follow-up echocardiography, there was a trend towards the highest dilatation rates of sinus of Valsalva and STJ amongst Indian, and AA amongst Malay groups. Kaplan-Meier curves showed the highest incidence of total events amongst Chinese, followed by Malay, Indian and Eurasian (log-rank=9.691; p=0.021) patients. CONCLUSION: There were differences in BAV morphology, valve dysfunction, aortopathy, and prognosis within the Asian population. Chinese patients had one of the highest prevalence of significant aortic regurgitation, with the largest aortic dimensions and worst outcomes compared with other Asian ethnicities. Closer surveillance is warranted in BAV patients within the Asian population.

Plasma Clearance of B-Type Natriuretic Peptide (BNP) before and after Bariatric Surgery for Morbid Obesity.

BACKGROUND: Obese patients have lower plasma concentrations of the cardiac natriuretic peptides (NPs) than their age- and sex-matched counterparts. This may reflect lower production and/or increased peptide clearance. It is unclear whether NP bioactivity is affected by obesity. METHODS: We studied the effects of obesity on B-type natriuretic peptide (BNP) clearance and bioactivity by comparing results from standardized intravenous infusions of BNP administered 2 weeks before and 6 months after bariatric surgery in 12 consecutive patients with morbid obesity (body mass index, BMI > 35 kg/m2). Anthropometric, clinical, neurohormonal, renal, and echocardiographic variables were obtained pre- and postsurgery. Pre- vs postsurgery calculated intrainfusion peptide clearances were compared. RESULTS: BMI (44.3 ± 5.0 vs 33.9 ± 5.2 kg/m2, P < 0.001) and waist circumference (130.3 ± 11.9 vs 107.5 ± 14.7 cm, P < 0.001) decreased substantially after bariatric surgery. Calculated plasma clearance of BNP was reduced (approximately 30%) after surgery. Though not controlled for, sodium intake was presumably lower after bariatric surgery. Despite this, preinfusion endogenous plasma NP concentrations did not significantly differ between pre- and postsurgery studies. The ratio of plasma N-terminal (NT)-proBNP to 24 h urine sodium excretion was higher postsurgery (P = 0.046; with similar nonsignificant findings for BNP, atrial NP (ANP) and NT-proANP), indicating increased circulating NPs for a given sodium status. Mean plasma NP concentrations for given calculated end-systolic wall stress and cardiac filling pressures (as assessed by echocardiographic E/e') rose slightly, but not significantly postsurgery. Second messenger, hemodynamic, renal, and neurohormonal responses to BNP were not altered between studies. CONCLUSION: Obesity is associated with increased clearance, but preserved bioactivity, of BNP.

Utility of conventional clinical risk scores in a low-risk COVID-19 cohort.

BACKGROUND: Several specific risk scores for Coronavirus disease 2019 (COVID-19) involving clinical and biochemical parameters have been developed from higher-risk patients, in addition to validating well-established pneumonia risk scores. We compared multiple risk scores in predicting more severe disease in a cohort of young patients with few comorbid illnesses. Accurately predicting the progression of COVID-19 may guide triage and therapy. METHODS: We retrospectively examined 554 hospitalised COVID-19 patients in Singapore. The CURB-65 score, Pneumonia Severity Index (PSI), ISARIC 4C prognostic score (4C), CHA2DS2-VASc score, COVID-GRAM Critical Illness risk score (COVID-GRAM), Veterans Health Administration COVID-19 index for COVID-19 Mortality (VACO), and the "rule-of-6" score were compared for three performance characteristics: the need for supplemental oxygen, intensive care admission and mechanical ventilation. RESULTS: A majority of patients were young (≤ 40 years, n = 372, 67.1%). 57 (10.3%) developed pneumonia, with 16 (2.9% of study population) requiring supplemental oxygen. 19 patients (3.4%) required intensive care and 2 patients (0.5%) died. The clinical risk scores predicted patients who required supplemental oxygenation and intensive care well. Adding the presence of fever to the CHA2DS2-VASc score and 4C score improved the ability to predict patients who required supplemental oxygen (c-statistic 0.81, 95% CI 0.68-0.94; and 0.84, 95% CI 0.75-0.94 respectively). CONCLUSION: Simple scores including well established pneumonia risk scores can help predict progression of COVID-19. Adding the presence of fever as a parameter to the CHA2DS2-VASc or the 4C score improved the performance of these scores in a young population with few comorbidities.

An Asian Perspective on Gender Differences in Clinical Outcomes and Echocardiographic Profiles of Patients With Medically Managed Severe Aortic Stenosis.

BACKGROUND: Gender differences in valvular heart disease are increasingly recognised. A prior study has suggested better surgical outcomes in women with symptomatic aortic stenosis (AS). We investigate gender differences in medically managed severe AS. METHOD: We studied 347 patients with severe AS (aortic valve area index <0.6 cm2/m2) in terms of baseline clinical background, echocardiographic characteristics, and clinical outcomes. Appropriate univariate and multivariate models were employed, while Kaplan-Meier curves were constructed to compare mortality outcomes. RESULTS: In total, 205 (59%) patients were women. Despite higher incidences of hypertension (75.6% vs 47.3%) and diabetes mellitus (46.5% vs 29.5%) in women, women had improved survival (Kaplan-Meier log-rank = 6.24, p = 0.012). After adjusting for age (hazard ratio [HR], 1.034; 95% confidence interval [CI], 1.014-1.054), hypertension (HR, 1.469; 95% CI, 0.807-2.673), diabetes (HR, 1.219; 95% CI, 0.693-2.145), and indexed aortic valve area (HR 0.145, 95% CI 0.031-0.684) on multivariate analyses, female gender remained independently associated with lower mortality (HR, 0.561; 95%, CI 0.332-0.947). Women tended to have smaller body surface area (BSA), left ventricular (LV) internal diastolic diameter, and smaller LV outflow tract diameter but were similar to men in terms of LV ejection fraction, AS severity, and patterns of LV remodelling. CONCLUSIONS: Women appeared to have better outcomes compared to men in medically managed severe AS. These gender differences warrant further study and may affect prognosis, follow-up, and timing of valve surgery.

Differences in Clinical and Echocardiographic Profiles and Outcomes of Patients With Atrial Fibrillation Versus Sinus Rhythm in Medically Managed Severe Aortic Stenosis and Preserved Left Ventricular Ejection Fraction.

BACKGROUND: Atrial fibrillation (AF) results in the loss of atrial booster pump function and portends poorer outcome in aortic valve stenosis (AS). However, its characteristics and impact on medically managed AS remained under-recognised. We compared these patients with AF to sinus rhythm (SR). METHOD: In total, 347 consecutive patients with medically managed severe AS (aortic valve area <1 cm2) and preserved left ventricular ejection fraction (>50%) were studied, in terms of echocardiographic characteristics and clinical outcomes. Appropriate univariate and multivariate models were used, while Kaplan-Meier curves and Cox regression models were constructed to compare clinical outcomes (mortality, admissions for congestive cardiac failure, and stroke). RESULTS: Ninety (90) (25.9%) patients had AF. Patients with AF had lower body mass index (BMI 18.5±10.4 vs 23.8±6.2 g/m2; p<0.001), larger left ventricular mass index (LVMI 127.9±39.0 vs 116.7±36.5; p=0.017), and left atrial volume index (53.2±20.0 vs 31.0±9.2 mL/m2; p=0.004). Atrial fibrillation was associated with higher mortality (52.2% vs 37.4%; Kaplan-Meier log-rank 7.18; p=0.007), admissions for congestive cardiac failure (log-rank 6.42; p=0.011), and poorer composite outcomes (log-rank 6.29; p=0.012). The incidence of stroke in both groups were similar on follow-up (log-rank 0.08; p=0.776). After adjusting for age, BMI, LVMI, and left atrial volume index on Cox regression, AF remained independently associated with poorer composite clinical outcomes (hazard ratio, 1.66; 95% confidence interval 1.07-2.58). CONCLUSIONS: Atrial fibrillation remained an important comorbidity affecting a quarter of patients with medically managed severe AS. It was independently associated with poorer clinical outcomes and may thus aid in prognostication and management.

Predicting changes in flow category in patients with severe aortic stenosis and preserved left ventricular ejection fraction on medical therapy.

BACKGROUND/OBJECTIVES: Controversy surrounds the prognosis and management of patients with paradoxical low-flow severe aortic stenosis (AS) with preserved left ventricular ejection fraction (LVEF). It was not certain if patients in a particular flow category remained in the same category as disease progressed. We investigated whether there were switches in categories and if so, their predictors. METHODS: Consecutive subjects (n = 203) with isolated severe AS and paired echocardiography (>180 days apart) were studied. They were divided into 4 groups, based on their flow categories and if they progressed on subsequent echocardiography to switch or remain in the same flow category. Univariate analyses of clinical and echocardiographic parameters identified predictors of these changes in flow category. RESULTS: One hundred eighteen were normal flow (SVI ≥ 35 mL/m2 ), while 85 were low flow on index echocardiography. In the patients with normal flow, 33% switched to low flow. This was associated with higher valvuloarterial impedance (Zva, P < .001) and lower systemic arterial compliance (SAC, P < .001) compared to index echocardiography, and predicted by higher initial Zva (optimized cutoff >4.77 mm Hg/mL/m2 , AUC = 0.81 [95% CI:0.75-0.87, P < .001]). In patients with low flow, 25% switched to normal flow, which was associated with lower Zva and higher SAC and the switch was predicted by a higher initial mean transaortic pressure gradient. CONCLUSIONS: A significant number of patients switched flow categories in severe AS with preserved LVEF on subsequent echocardiography. Changes in flow were reflected by respective changes in Zva and SAC. Identifying echocardiographic predictors of a switch in category may guide prognostication and management of such patients.

Comparing characteristics and clinical and echocardiographic outcomes in low-flow vs normal-flow severe aortic stenosis with preserved ejection fraction in an Asian population.

BACKGROUND/OBJECTIVES: In severe aortic stenosis (AS), deterioration of left ventricular ejection fraction (LVEF) to <50% is an AHA/ACC class I indication for valve replacement, regardless of symptoms. Controversy surrounds prognosis of low-flow AS compared to normal-flow, and no study has examined LVEF deterioration. We compared factors associated with LVEF deterioration (to <50%) and clinical outcomes. METHODS: Consecutive subjects with low-flow (stroke volume index <35 mL/m2 , n=56) and normal-flow (n=72) severe AS (aortic valve area <1 cm2 ) with preserved LVEF (>50%) and with paired echocardiography were studied. Univariate and multivariate analyses identified factors associated with LVEF deterioration. Clinical outcomes were determined on follow-up for more than 5 years. RESULTS: Significant LVEF deterioration (to <50%) was seen in 18% of low-flow (initial LVEF 63±8% to 32±9%) and 18% of normal-flow AS (61±7% to 31±12%). Independent factors in low-flow AS were hypertension (OR: 30.7, 95% CI: 2.0-467.6, P=.014) and higher end-systolic wall stress (OR: 1.086, 95% CI: 1.022-1.153, P=.008), compared to normal-flow, which were hypertension (OR: 15.9, 95% CI: 3.1-81.9, P=.001), higher septal E/E' ratio (OR: 1.16, 95% CI: 1.01-1.35, P=.043), lower septal S' velocity (OR: 0.204, 95% CI: 0.061-0.682, P=.010), and higher end-systolic wall stress (OR: 1.051, 95% CI: 1.001-1.104, P=.047). Overall, a third of the cohort experienced MACE, regardless of flow (log-rank 0.048, P=.827). However, aortic valve replacement (AVR) rates were lower in low-flow AS (20% vs 43%, P=.005). CONCLUSIONS: Low-flow AS despite normal LVEF appears similar to normal-flow in terms of LVEF deterioration and clinical outcomes in our Asian population. AVR rate was lower even though low-flow may not reflect less severe disease.

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.

Does Prior Respiratory Viral Infection Provide Cross-Protection Against Subsequent Respiratory Viral Infections? A Systematic Review and Meta-Analysis.

The epidemiology of different respiratory viral infections is believed to be affected by prior viral infections in addition to seasonal effects. This PROSPERO-registered systematic review identified 7388 studies, of which six met our criteria to answer the question specifically. The purpose of this review was to compare the prevalence of sequential viral infections in those with previously documented positive versus negative swabs. The pooled prevalence of sequential viral infections over varying periods from 30-1000 days of follow-up was higher following a negative respiratory viral swab at 0.15 than following a positive swab at 0.08, indicating the potential protective effects of prior respiratory viral infections. However, significant heterogeneity and publication biases were noted. There is some evidence, albeit of low quality, of a possible protective effect of an initial viral infection against subsequent infections by a different virus, which is possibly due to broad, nonspecific innate immunity. Future prospective studies are needed to validate our findings.

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.

Increased left ventricular remodelling index in paradoxical low-flow severe aortic stenosis with preserved left ventricular ejection fraction compared to normal-flow severe aortic stenosis.

INTRODUCTION: Patients with paradoxical low-flow (LF) severe aortic stenosis (AS) despite preserved left ventricular ejection fraction (LVEF) appear distinct from normal-flow (NF) patients, showing worse prognosis, more concentric hypertrophy and smaller left ventricular (LV) cavities. The left ventricular remodelling index (LVRI) has been demonstrated to reliably discriminate between physiologically adapted athlete's heart and pathological LV remodelling. METHODS: We studied patients with index echocardiographic diagnosis of severe AS (aortic valve area <1 cm2) with preserved LVEF (>50%). The LVRI was determined by the ratio of the LV mass to the end-diastolic volume, as previously reported, and was compared between patients with LF and NF AS. Patients were prospectively followed up for at least 3 years, and clinical outcomes were examined in association with LVRI. RESULTS: Of the 450 patients studied, 112 (24.9%) had LF AS. While there were no significant differences in baseline clinical profile between LF and NF patients, LVRI was significantly higher in the LF group. Patients with high LVRI (>1.56 g/mL) had increased all-cause mortality (log-rank 9.18, P = 0.002) and were more likely to be admitted for cardiac failure (log-rank 7.61, P = 0.006) or undergo aortic valve replacement (log-rank 18.4, P < 0.001). After adjusting for the effect of age, hypertension, aortic valve area and mean pressure gradient on multivariate Cox regression, high LVRI remained independently associated with poor clinical outcomes (hazard ratio 1.64, 95% confidence interval 1.19-2.25, P = 0.002). CONCLUSION: Pathological LV remodelling (increased LVRI) was more common in patients with LF AS, and increased LVRI independently predicts worse clinical outcomes.

A review of COVID-19 vaccination and the reported cardiac manifestations.

In Singapore, 9.03 million doses of the mRNA COVID-19 vaccines by Pfizer-BioNTech and Moderna have been administered, and 4.46 million people are fully vaccinated. An additional 87,000 people have been vaccinated with vaccines in World Health Organization's Emergency Use Listing. The aim of this review is to explore the reported cardiac adverse events associated with different types of COVID-19 vaccines. A total of 42 studies that reported cardiac side effects after COVID-19 vaccination were included in this study. Reported COVID-19 vaccine-associated cardiac adverse events were mainly myocarditis and pericarditis, most commonly seen in adolescent and young adult male individuals after mRNA vaccination. Reports of other events such as acute myocardial infarction, arrhythmia and stress cardiomyopathy were rare. Outcomes of post-vaccine myocarditis and pericarditis were good. Given the good vaccine efficacy and the high number of cases of infection, hospitalisation and death that could potentially be prevented, COVID-19 vaccine remains of overall benefit, based on the current available data.

Continued demographic shifts in hospitalised patients with COVID-19 from migrant workers to a vulnerable and more elderly local population at risk of severe disease.

OBJECTIVES: In the early months of the COVID-19 pandemic in Singapore, the vast majority of infected persons were migrant workers living in dormitories who had few medical comorbidities. In 2021, with the Delta and Omicron waves, this shifted to the more vulnerable, elderly population within the local community. We examined evolving trends among the hospitalised cases of COVID-19. METHODS: All patients with polymerase chain reaction-positive SARS-CoV-2 admitted from February 2020 to October 2021 were included and subsequently stratified by their year of admission (2020 or 2021). We compared the baseline clinical characteristics, clinical course, and outcomes. RESULTS: A majority of cases were seen in 2020 (n = 1359), compared with 2021 (n = 422), due to the large outbreaks in migrant worker dormitories. Nevertheless, the greater proportion of locally transmitted cases outside of dormitories in 2021 (78.7% vs 12.3%) meant a significantly older population with more medical comorbidities had COVID-19. This led to an observably higher proportion of patients with severe disease presenting with raised inflammatory markers, need for therapeutics, supplemental oxygenation, and higher mortality. CONCLUSION: Changing demographics and the characteristics of the exposed populations are associated with distinct differences in clinical presentation and outcomes. Older age remained consistently associated with adverse outcomes.