Publications by authors named "Kelvin Bryan Tan"

Objectives: Most studies on long-term sequelae of SARS-CoV-2-infection in children were conducted pre-Omicron and pre-dated vaccination rollout. We examined long-term risk of new-incident multi-systemic sequelae after SARS-CoV-2 Delta/Omicron infection in a multi-ethnic Asian pediatric population.

Methods: Retrospective cohort study of Singaporean children aged 1- 17 years infected during Delta/Omicron BA.

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Background: Vaccination has been shown to attenuate the risk of post-acute sequelae following SARS-CoV-2 infection. However, no prior population-based studies have evaluated if updated bivalent boosters reduce risk of post-acute sequelae following Omicron-variant infection, versus ancestral vaccines.

Methods: National databases were utilised to construct a population-based cohort of adult individuals infected during Omicron-predominant transmission.

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The ISARIC 4C Mortality score was developed to predict mortality risk among patients with COVID-19. Its performance among vaccinated individuals is understudied. This is a retrospective study of all patients with SARS-CoV-2 infection admitted to the National Centre for Infectious Diseases, Singapore, from January-2020 to December-2021.

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Mental health issues have increased substantially since the onset of the COVID-19 pandemic. However, health policymakers do not have adequate data and tools to predict mental health demand, especially amid a crisis. Using time-series data collected in Singapore, this study examines if and how algorithmically measured emotion indicators from Twitter posts can help forecast emergency mental health needs.

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Article Synopsis
  • The study assesses the population-wide risk-benefit ratio of COVID-19 vaccination during the Omicron variant phase, focusing on mortality and cardiovascular events post-vaccination and infection.
  • Conducted in Singapore from January to December 2022 with over 3 million participants, researchers utilized Cox regression to evaluate risks for various timeframes post-vaccination/infection.
  • Results showed no increased risk of mortality or cardiovascular events after vaccination, but older adults had elevated mortality risks after infection, particularly with vaccine-breakthrough infections, while cardiovascular risks were higher 1-2 months post-infection across all age groups.
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Unpredictable emergency department (ED) admissions challenge healthcare systems, causing resource allocation inefficiencies. This study analyses associations between air pollutants, meteorological factors, and 2,655,861 cause-specific ED admissions from 2014 to 2018 across 12 categories. Generalized additive models were used to assess non-linear associations for each exposure, yielding Incidence Rate Ratios (IRR), while the population attributable fraction (PAF) calculated each exposure's contribution to cause-specific ED admissions.

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Article Synopsis
  • * Results indicated that CPAP therapy is highly cost-effective, with an incremental cost-effectiveness ratio of $13,822 per disability-adjusted life year (DALY) averted, significantly below the US threshold of $50,000 per DALY.
  • * The analysis highlighted that treatment costs, as well as patient adherence rates (which need to be at least 16.1% for cost-effectiveness), are critical factors influencing the overall economics of CPAP therapy, providing insights for healthcare policymakers.
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Objectives: Significant heterogeneity has been reported in cohort studies evaluating the impact of early oral antiviral treatment on preventing postacute sequelae after COVID-19. We evaluated the impact of early nirmatrelvir/ritonavir on risk of postacute cardiovascular, neurological, respiratory, and autoimmune diagnoses, as well as postacute symptoms amongst older Singaporeans.

Methods: National COVID-19 registries and healthcare claims databases were used to construct a retrospective population-based cohort enrolling all Singaporeans aged ≥60 years diagnosed with SARS-CoV-2 infection in primary care during Omicron transmission (18 March 2022-4 August 2023).

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Importance: Studies have reported increased risk of autoimmune sequelae after SARS-CoV-2 infection. However, risk may potentially be attenuated by milder Omicron (B.1.

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Article Synopsis
  • A study was conducted in Singapore to explore whether having a prior dengue infection affects the risk and severity of getting COVID-19, particularly in a population where both diseases can overlap.
  • Researchers analyzed data from over 3 million individuals, looking at the relationship between prior dengue infections and subsequent SARS-CoV-2 cases during a time of increased COVID-19 transmission from Delta and Omicron variants.
  • The findings revealed that prior dengue infections slightly increase the risk of contracting SARS-CoV-2 and significantly heighten the likelihood of hospitalization and severe outcomes from COVID-19.
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Vaccination against COVID-19 was integral to controlling the pandemic that persisted with the continuous emergence of SARS-CoV-2 variants. Using a mathematical model describing SARS-CoV-2 within-host infection dynamics, we estimate differences in virus and immunity due to factors of infecting variant, age, and vaccination history (vaccination brand, number of doses and time since vaccination). We fit our model in a Bayesian framework to upper respiratory tract viral load measurements obtained from cases of Delta and Omicron infections in Singapore, of whom the majority only had one nasopharyngeal swab measurement.

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Background: Data on protection afforded by updated coronavirus disease 2019 (COVID-19) vaccines (bivalent/XBB 1.5 monovalent) against the emergent JN.1 variant remain limited.

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Background: Cognitive impairment (CI) raises risks for unplanned healthcare utilisation and expenditures and for premature mortality. It may also reduce risks for planned expenditures. Therefore, the net cost implications for those with CI remain unknown.

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Objectives: Evidence suggests that some COVID-19 survivors experience a wide range of post-COVID-19 sequelae; however, the majority of studies were conducted before the emergence of the milder Omicron variant. We examined the post-acute risk of new-incident cardiovascular complications after SARS-CoV-2 infection in a multi-ethnic Asian population, during Omicron predominance.

Methods: This cohort study used national testing and healthcare claims databases in Singapore to build a cohort of individuals with confirmed SARS-CoV-2 infection during Omicron BA.

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Background: Individuals with chronic lung disease (CLD) are more susceptible to respiratory viral infections; however, significant heterogeneity exists in the literature on CLD and COVID-19 outcomes. Data are lacking on outcomes with newer variants (eg, Omicron) and in vaccinated and boosted populations.

Research Question: What are the outcomes of SARS-CoV-2 infection in individuals with CLD during Delta and Omicron transmission in a highly vaccinated and boosted population-based cohort?

Study Design And Methods: Outcomes of Delta and Omicron SARS-CoV-2 infection in a highly vaccinated and boosted cohort of adult Singaporeans with CLD (including asthma, COPD, bronchiectasis, and pulmonary fibrosis) were contrasted against matched population control participants.

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Background: While persistence of chronic symptoms following dengue infection has been documented in small prospective cohorts, population-based studies are limited. The post-acute risk of new-incident multi-systemic complications following dengue infection was contrasted against that following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in a multi-ethnic adult Asian population.

Methods: National testing and healthcare claims that databases in Singapore were utilized to build a retrospective population-based adult cohort with laboratory-confirmed infection during overlapping waves of SARS-CoV-2 and dengue transmission (1 July 2021 to 31 October 2022).

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Objective: There is a paucity of studies investigating the outcomes among Asian stroke patients. Identifying subgroups of stroke patients at risk of poorer outcomes could identify patients who would benefit from targeted interventions. Therefore, the aim of this study was to identify which ischemic stroke patients at high risk of recurrent events and mortality.

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Since the start of the pandemic, many national responses, such as nationwide lockdowns, have been implemented to curb the spread of COVID-19. We aim to assess the impact of Singapore's national responses on primary care utilisation. We performed an interrupted time series using acute and chronic primary care data of 3 168 578 visits between 1 September 2019 and 31 August 2020 over four periods: before any measures were put in place, during Disease Outbreak Response System Condition (DORSCON) Orange, when Circuit Breaker was instituted, and when Circuit Breaker was lifted.

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Article Synopsis
  • A study analyzed long-term neuropsychiatric issues following SARS-CoV-2 infections using health data from vaccinated Singaporean adults during Delta and Omicron waves.
  • The research involved comparing 104,179 Delta and 375,903 Omicron cases with a control group, revealing higher risks of cognitive disorders and specific neuropsychiatric conditions linked to each variant.
  • The findings showed a cautious increase in cognitive disorder risks post-infection, particularly in hospitalized patients, but no significant overall rise in neuropsychiatric issues.
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Introduction: Though hip fractures are associated with significant mortality and morbidity, increasing life expectancy in developed countries necessitates an analysis of mortality trends and factors predicting long term survival. The aim of this study is to identify the predictors of 10-year mortality as well as assess the correlation of Age-adjusted Charlson comorbidity index (ACCI) with 10-year mortality in a surgically treated Asian geriatric hip fracture population.

Materials And Methods: From January 1, 2007 to December 31, 2009, 766 patients who underwent surgery for hip fracture with a minimum follow up of 10-years were recruited to the study (92% follow-up rate).

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