Differences in virus and immune dynamics for SARS-CoV-2 Delta and Omicron infections by age and vaccination histories.

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. With this dataset, we are able to recreate similar trends in URT virus dynamics observed in past within-host modelling studies fitted to longitudinal patient data.We found that Omicron had higher R0,within values than Delta, indicating greater initial cell-to-cell spread of infection within the host. Moreover, heterogeneities in infection dynamics across patient subgroups could be recreated by fitting immunity-related parameters as vaccination history-specific, with or without age modification. Our model results are consistent with the notion of immunosenescence in SARS-CoV-2 infection in elderly individuals, and the issue of waning immunity with increased time since last vaccination. Lastly, vaccination was not found to subdue virus dynamics in Omicron infections as well as it had for Delta infections.This study provides insight into the influence of vaccine-elicited immunity on SARS-CoV-2 within-host dynamics, and the interplay between age and vaccination history. Furthermore, it demonstrates the need to disentangle host factors and changes in pathogen to discern factors influencing virus dynamics. Finally, this work demonstrates a way forward in the study of within-host virus dynamics, by use of viral load datasets including a large number of patients without repeated measurements.

Long-term cardiovascular, cerebrovascular, and thrombotic complications after SARS-CoV-2-Omicron infection: a retrospective cohort study.

OBJECTIVES: Evidence suggests that some COVID-19 survivors experience a wide range of post-COVID-19 sequelae; however, the majority of studies were conducted prior to 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.1/2 transmission, and a contemporaneous test-negative group. Participants in both groups were followed up for a median of 300 days. We estimated risks of new-incident cardiovascular complications using doubly robust competing-risks survival analysis. Risks were reported using two measures: hazard ratio (HR) and excess burden (EB). RESULTS: We included 375,903 test-positive, infected individuals (mean age 48 years) and 619,379 test-negative controls (mean age 47 years). The majority (97.5%, 366,593/375,903) of infected individuals had mild infection not requiring hospitalisation. There was no overall increased risk of new-incident cardiovascular complications, (adjusted-hazards-ratio, aHR = 1.01 [0.97-1.07]) amongst COVID-19 survivors when compared against test-negatives. A modestly increased risk and excess burden of dysrhythmias amongst COVID-19 survivors (aHR=1.09 [1.01- 1.19]) was observed. Risk and burdens of new-incident cardiovascular complications predominantly accrued in hospitalised (aHR=5.52 [3.76-8.10]) and severe (aHR=5.52 [3.76-8.10]) COVID-19 cases. CONCLUSIONS: No significantly increased overall risk of any cardiovascular complication was observed in the 300 days following COVID-19 infection during the Omicron-dominant period when compared against test-negatives, with the exception of a small increased occurrence of dysrhythmias.

Healthcare burden of cognitive impairment: Evidence from a Singapore Chinese health study.

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. Method: We examined differences in healthcare utilisation and cost between those with and without CI. Using administrative healthcare utilisation and cost data linked to the Singapore Chinese Health Study cohort, we estimated regression-adjusted differences in annual healthcare utilisation and costs by CI status determined by modified Mini-Mental State Exam. Estimates were stratified by ex ante mortality risk constructed from out-of-sample Cox model predictions applied to the full sample, with a separate analysis restricted to decedents. These estimates were used to project differential healthcare costs by CI status over 5 years. Results: Patients with CI had 17% higher annual cost compared to those without CI (SGD4870 versus SGD4177, P<0.01). Accounting for the greater mortality risk, individuals with CI cost 9% to 17% more over 5 years, or SGD2500 (95% confidence interval 1000-4200) to SGD3600 (95% confidence interval 1300-6000) more, depending on their age. Higher cost was mainly due to more emergency department visits and subsequent admissions (i.e. unplanned). Differences attenuated in the last year of life when costs increased dramatically for both groups. Conclusion: Ageing populations and higher rates of CI will further strain healthcare resources primarily through greater use of emergency department visits and unplanned admissions. Efforts should be made to identify at risk patients with CI and take appropriate remediation strategies.

Risks of SARS-CoV-2 JN.1 infection and COVID-19 associated emergency-department (ED) visits/hospitalizations following updated boosters and prior infection: a population-based cohort study.

INTRODUCTION: Data on protection afforded by updated COVID-19 vaccines (bivalent/XBB 1.5 monovalent) against the emergent JN.1 variant remains limited. METHODS: We conducted a retrospective population-based cohort study amongst all boosted Singaporeans aged ≥18 years during a COVID-19 wave predominantly driven by JN.1, from 26th November 2023 to 13th January 2024. Multivariable Cox regression was utilised to assess risk of SARS-CoV-2 infection and COVID-19 associated emergency-department (ED) visits/hospitalizations, stratified by vaccination status/prior infection; with individuals last boosted ≥1 year utilized as the reference category. Vaccination and infection status were classified using national registries. RESULTS: 3,086,562 boosted adult Singaporeans were included in the study population, accounting for 146,863,476 person-days of observation. During the JN.1 outbreak, 28,160 SARS-CoV-2 infections were recorded, with 2,926 hospitalizations and 3,747 ED-visits. Compared with individuals last boosted ≥1 year prior with ancestral monovalent vaccines, receipt of an updated XBB.1.5 booster 8-120 days prior was associated with lower risk of JN.1 infection (adjusted-hazard-ratio, aHR = 0.59[0.52-0.66]), COVID-19 associated ED-visits (aHR = 0.50[0.34-0.73]) and hospitalizations(aHR = 0.58[0.37-0.91]), while receipt of a bivalent booster 121-365 days prior was associated with lower risk of JN.1 infection (aHR = 0.92[0.88-0.95]) and ED-visits (aHR = 0.80[0.70-0.90]). Lower risk of COVID-19 hospitalization during the JN.1 outbreak (aHR = 0.57[0.33-0.97]) was still observed following receipt of an updated XBB.1.5 booster 8-120 days prior, even when analysis was restricted to previously infected individuals. CONCLUSION: Recent receipt of updated boosters conferred protection against SARS-CoV-2 infection and ED-visits/hospitalization during a JN.1 variant wave, in both previously infected and uninfected individuals. Annual booster doses confer protection during COVID-19 endemicity.

Dengue versus COVID-19: comparing the incidence of cardiovascular, neuropsychiatric and autoimmune complications.

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). Risks of new-incident cardiovascular/neuropsychiatric/autoimmune complications 31-300 days of post-dengue infection, contrasted with SARS-CoV-2 infection, were estimated using Cox regression with overlap weights. Risks were reported in terms of adjusted hazard ratio (aHR) and excess burden per 1000 persons. RESULTS: 11 707 dengue-infected individuals and 1 248 326 contemporaneous coronavirus disease 2019 (COVID-19) cases were included; the majority had mild initial infection not requiring hospitalization. Amongst dengue-infected individuals, there was 21% [aHR = 1.21 (1.06-1.38)] increased risk of any sequelae, with 55% [aHR = 1.55 (1.27-1.89)] increased risk of cardiovascular sequelae. Specifically, increased risk of dysrhythmias [aHR = 1.79(1.35-2.37)], ischemic heart disease [aHR = 1.45(1.12-1.89)], other cardiac disorders [aHR = 2.21(1.54-3.16)] and thrombotic disorders [aHR = 2.55(1.50-4.35)] was noted. Elevated risk of individual neuropsychiatric sequelae, including cerebrovascular disorders [aHR = 1.49(1.09-2.13)], cognition/memory disorders [aHR = 2.13(1.55-2.93)], extrapyramidal/movement disorders [aHR = 1.98(1.33-2.94)] and anxiety disorders [aHR = 1.61(1.01-2.56)], was observed in dengue-infected individuals compared to COVID-19 cases. Elevated risks of post-acute sequelae in dengue survivors were observed when contrasted against COVID-19 survivors infected during Delta/Omicron predominance, as well as across vaccination strata. CONCLUSION: Increased risk of post-acute cardiovascular/neuropsychiatric complications was observed in dengue survivors, when contrasted against COVID-19 survivors infected during Delta/Omicron predominance.

A Nationwide Cohort Study of Delta and Omicron SARS-CoV-2 Outcomes in Vaccinated Individuals With Chronic Lung Disease.

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. Calendar time-scale Cox regressions were used to compare risk of infection, COVID-19-related hospitalizations, and severe COVID-19 disease, adjusting for sociodemographic factors and comorbidities. RESULTS: Overall, 68,782 individual patients with CLD and 534,364 matched population control participants were included. By the end of the Omicron wave, 92.7% of patients with CLD were boosted. Compared with control participants, patients with CLD showed higher risk of SARS-CoV-2 infection, COVID-19-related hospitalization, and severe COVID-19 during both the Delta wave (infection: adjusted hazards ratio [aHR], 1.22 [95% CI, 1.17-1.28]; hospitalization: aHR, 1.76 [95% CI, 1.61-1.92]; severe COVID-19: aHR, 1.75 [95% CI, 1.50-2.05]) and Omicron wave (infection: aHR, 1.15 [95% CI, 1.14-1.17]; hospitalization: aHR, 1.82 [95% CI, 1.74-1.91]; severe COVID-19: aHR, 2.39 [95% CI, 2.18-2.63]). During Omicron, significantly higher risk of infection, hospitalization, and severe COVID-19 was observed among patients with asthma (severe COVID-19: aHR, 1.31 [95% CI, 1.10-1.55]) and COPD (severe COVID-19: aHR, 1.36 [95% CI, 1.12-1.66]) compared with control participants. Severe exacerbation (requiring hospitalization) in the preceding year was associated with higher risk of poorer outcomes (Delta severe COVID-19: aHR, 9.84 [95% CI, 6.33-15.28]; Omicron severe COVID-19: aHR, 19.22 [95% CI, 15.35-24.06]). Risk was attenuated in the boosted group, with numerically lower HRs against hospitalization and severe COVID-19 in the four-dose group compared with the three-dose group. INTERPRETATION: Increased risk of COVID-19-related hospitalization and severe COVID-19 was observed among patients with CLD compared with matched population control participants during Delta and Omicron predominance. Boosting attenuated serious COVID-19 outcomes.

Associated demographic factors for the recurrence and prognosis of stroke patients within a multiethnic Asian population.

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. METHODS: This cohort study adhered to STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) guidelines. We obtained data from the Singapore Stroke Registry (SSR) from 2005 to 2016 and cross referenced to the Death Registry and the Myocardial Infarction Registry. Outcome measures included recurrent stroke, acute myocardial infarction (AMI), and all-cause and stroke-related deaths. Multivariable Cox proportional hazards regression models were performed to determine risk factors for recurrent stroke, AMI, and all-cause and stroke-related deaths. RESULTS: A total of 64,915 patients (6705 young, and 58,210 older) were included in our analysis. Older stroke patients were found to have an increased risk of recurrent stroke (hazard ratio (HR) = 1.21, 95% confidence interval (CI) = 1.12-1.30), AMI (HR = 1.73, 95% CI = 1.54-1.95), all-cause death (HR = 2.49, 95% CI = 2.34-2.64), and stroke-related death (HR = 176, 95% CI = 1.61-1.92). Among young stroke patients, males were at increased risk for recurrent stroke (HR = 1.18, 95% CI = 1.01-1.39) and AMI (HR = 1.41, 95% CI = 1.08-1.83), but at reduced risk for all-cause (HR = 0.78, 95% CI = 0.69-0.89) and stroke-related deaths (HR = 0.79, 95% CI = 0.67-0.94). Ethnicity appeared to influence outcomes, with Malay patients at increased risk of recurrent stroke (HR = 1.37, 95% CI = 1.14-1.65), AMI (HR = 2.45, 95% CI = 1.87-3.22), and all-cause (HR = 1.43, 95% CI = 1.24-1.66) and stroke-related deaths (HR = 1.34, 95% CI = 1.09-1.64). Indian patients were also at increased risk of AMI (HR = 1.96, 95% CI = 1.41-2.72). Similar findings were seen among the older stroke patients. CONCLUSION: This study found that older stroke patients are at risk of poorer outcomes. Within the young stroke population specifically, males were predisposed to recurrent stroke and AMI but were protected against all-cause and stroke-related deaths. Males were also at reduced risk of all-cause and stroke-related deaths in the older stroke population. In addition, Malay and Indian patients experience poorer outcomes after first stroke. Further optimization of risk factors targeting these high-priority populations are needed to achieve high-quality care.

Total knee arthroplasty: does ultra-early physical therapy improve functional outcomes and reduce length of stay? A retrospective cohort study.

BACKGROUND: The Enhanced Recovery After Surgery (ERAS) Society recommends that after total knee arthroplasty (TKA), patients should be mobilized early. However, there is no consensus on how early physical therapy should be commenced. We aim to investigate whether ultra-early physical therapy (< 12 h postoperatively) leads to better outcomes. METHODS: This is a retrospective cohort study of 569 patients who underwent primary TKA from August 2017 to December 2019 at our institution. We compared patients who had undergone physical therapy either within 24 h or 24-48 h after TKA. Further subgroup analysis was performed on the < 24 h group, comparing those who had undergone PT within 12 h and within 12-24 h. The outcomes analyzed include the Oxford Knee Scoring System score, Knee Society Scores, range of motion (ROM), length of stay (LOS) and ambulatory distance on discharge. A student's t test, chi-squared test or Fisher's exact test was used where appropriate, to determine statistical significance of our findings. RESULTS: LOS in the < 24 h group was shorter compared to the 24-48 h group (4.87 vs. 5.34 days, p = 0.002). Subgroup analysis showed that LOS was shorter in the ultra-early PT (< 12 h) group compared to the early PT (12-24 h) group (4.75 vs. 4.96 days, p = 0.009). At 3 months postoperatively, there was no significant difference in ROM, ambulatory distance or functional scores between the < 24 h group and 24-48 h group, or on subgroup analysis of the < 24 h group. CONCLUSION: Patients who underwent physical therapy within 24 h had a shorter length of stay compared to the 24-48 h group. On subgroup analysis, ultra-early (< 12 h) physical therapy correlated with a shorter length of stay compared to the 12-24 h group (4.75 vs. 4.96 days, p = 0.009) - however, the difference is small and unlikely to be clinically significant. Ultra-early (< 12 h) physical therapy does not confer additional benefit in terms of functional scores, ROM or ambulatory distance. These findings reinforce the importance of early physical therapy after TKA in facilitating earlier patient discharge.

Percutaneous cholecystostomy in acute complicated versus uncomplicated cholecystitis; is there a difference in outcomes? A single-center experience.

BACKGROUND: Percutaneous cholecystostomy (PC) is a therapeutic intervention for acute cholecystitis. The benefits of cholecystostomy have been demonstrated in the medical literature, with up to 90% of acute cholecystitis cases shown to resolve postoperatively, and only 40% of patients subsequently undergoing an interval cholecystectomy. PURPOSE: To compare the survival outcomes between acute complicated and uncomplicated cholecystitis in patients undergoing PC as an initial intervention, as there is a paucity of evidence in the literature on this perspective. MATERIAL AND METHODS: A retrospective search was conducted of all patients who underwent PC for acute cholecystitis between August 2016 and December 2020 at a tertiary institution. A total of 100 patients were included in this study. RESULTS: The outcome, in the form of 30-day mortality, 90-day mortality, being alive after six months, and reintervention, was compared between complicated and uncomplicated cases using the chi-square test or Fisher's exact test. There was no statistically significant difference in any of the compared outcomes. The only variable that showed a statistically significant association with the risk of mortality was acute kidney injury (AKI) at admission. Patients who had stage 1, 2, or 3 AKI had a higher hazard for mortality as compared to patients with no kidney disease. CONCLUSION: Our results demonstrate that PC is a safe and effective procedure. Mortality is not affected by the presence of complications. The results have, however, highlighted the importance of recognizing and treating AKI, an independent risk factor affecting mortality.

Navigating drug use, cessation, and recovery: a retrospective case notes review among sexual minority men at a community-based service in Singapore.

BACKGROUND: In Singapore, where drug use is a highly stigmatized and criminalized issue, there is limited understanding of the challenges faced by individuals, particularly sexual minority men, in their journey towards recovery from substance dependence or addiction. This qualitative study aimed to investigate the driving forces behind drug use, the factors contributing to drug cessation, and the elements influencing the recovery process. METHODS: Data were extracted from clinical records provided by  The Greenhouse Community Services Limited between January 2020 to May 2022. These records encompassed information from four distinct forms: the intake assessment, progress notes, case closing summary, and the care plan review. Thematic analysis was employed to identify and categorize recurring themes within the data. RESULTS: Data from beneficiaries (n = 125) were analyzed and yielded a series of themes related to facilitators of drug use, motivations to cease drug use, and managing one's ongoing recovery. Within the facilitators of drug use, two sub-themes were identified: (a) addressing trauma and triggers and (b) managing emotions. Additionally, managing one's recovery was marked by four significant sub-themes: (a) uncovering personal identities, (b) losing motivation and drive, (c) overcoming obstacles, and (d) preparing for aftercare. CONCLUSIONS: The study contributes valuable insights into the dynamics of ongoing recovery management, offering potential avenues for interventions that could enhance support for individuals in their journey to overcome substance dependence. Enhancing psychoeducation and fostering peer support have the potential to facilitate the recovery process. Clearly, a holistic approach is needed to address these complex issues that cuts across our societies.

Shorter length of stay and significant cost savings with ambulatory surgery primary unilateral total knee arthroplasty in Asians using enhanced recovery protocols.

Introduction: Enhanced recovery after surgery (ERAS) in total knee arthroplasty (TKA) has reduced the length of stay (LOS) and cost of TKA in the Western population. Asians had been identified to be at higher odds of non-home discharge following TKA due to cultural differences. The efficacy of ERAS in TKA for Asian patients is less known. We aimed to investigate the efficacy of ERAS in reducing the LOS, transition to ambulatory surgery, improving home discharges, and reducing cost in an Asian population following TKA. Methods: Retrospective analysis was performed on 634 TKA patients in 2017 (pre- ERAS) and 584 TKA patients who had undergone ERAS in 2022 in a tertiary hospital. Results: Patients in 2022 (ERAS) were older (69 ± 7 vs. 68 ± 7 years old, p < 0.001) and had a higher proportion of patients with poorer function (p < 0.001). The LOS reduced from 5.4 days (95% CI:5.2-5.6) to 2.9 days (95% CI:2.7-3.2) (p < 0.001) with about 49 % of patients transitioning to ambulatory surgery and having a LOS of 1.4 days (95 %CI:1.3-1.5). The proportion of patients being discharged home in 2022 (78.9 %) was higher compared to 2017 (62.2 %) (p < 0.001). This saved the hospital 1817.4 inpatient ward bed days, which translated to S$2,124,540.60 of cost saving in a year, and up to S$2397.28 for the individual patient. Conclusion: ERAS after TKA was able to safely achieve LOS comparable to the western population and allowed transition to ambulatory knee replacement in the Asian population. Consequently, this led to higher proportion of home discharges and achieved significant cost saving and hospital bed days.

Impact of COVID-19 national response on primary care utilisation in Singapore: an interrupted time-series analysis.

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. We found significant mean reductions in acute and chronic primary care visits immediately following DORSCON Orange and Circuit Breaker. DORSCON Orange was associated with - 2020 mean daily visits (95% CI - 2890 to - 1150). Circuit Breaker was associated with a further - 2510 mean daily visits (95% CI - 3660 to - 1360). Primary care utilisation for acute visits remained below baseline levels even after the Circuit Breaker was lifted. These significant reductions were observed in both acute and chronic visits, with acute visits experiencing a steeper drop during DORSCON Orange. Understanding the impact of COVID-19 measures on primary care utilisation will be useful for future public health planning.

Myocardial Aging among a Population-Based Cohort Is Associated with Adverse Cardiovascular Outcomes and Sex-Specific Differences among Older Adults.

INTRODUCTION: Despite growing calls to tackle aging-related cardiovascular disease (CVD), the role of detecting early diastolic dysfunction such as those observed in aging, prior to clinical disease, is of unclear clinical benefit. METHODS: Myocardial function determined by echocardiography was examined in association with incident cardiovascular outcomes or all-cause death by Cox proportional hazards model. Sex-based differences in outcomes were included. RESULTS: A total of 956 participants (mean age 63 ± 12.9 years, n = 424 males [44%]) were categorized based on mitral peak early-to-late diastolic filling velocity (E/A) ratios: E/A <0.8 (28%), E/A 0.8-1.2 (39%), E/A (29%), E/A >2.0 (4%). Incidence rate (IR) for non-fatal cardiovascular outcomes was 2.83 per 100 person-years (95% CI: 2.24-3.56) and 0.45 per 100 person-years (95% CI: 0.26-0.80) for all-cause death. Event-free survival from non-fatal cardiovascular outcomes was significantly different among E/A categories (log-rank p = 0.0269). E/A <0.8 (HR 1.80, 95% CI: 1.031, 3.14, p = 0.039) was associated with non-fatal cardiovascular outcomes. Among men, IR for cardiovascular outcomes was 3.56 per 100 person-years (95% CI: 2.62-4.84) and 0.75 per 100 person-years (95% CI: 0.39-1.44) for all-cause death. Among women, IR for cardiovascular outcomes was 2.22 per 100 person-years (95% CI: 1.56-3.16) and 0.21 per 100 person-years (95% CI: 0.067-0.64) for all-cause death. For E/A <0.8 category, women had significantly higher risks of non-fatal cardiovascular outcomes, compared to E/A 0.8-1.2 category (HR 2.49, 95% CI: 1.18, 5.23, p = 0.017). CONCLUSION: Myocardial aging was an independent predictor of cardiovascular outcomes in community-dwelling older adults prior to clinical CVD. Impaired myocardial relaxation was prevalent in both sexes but associated with worse outcomes in women, suggestive of sex differences in age-related biology.

Empiric treatment with aspirin and ticagrelor is the most cost-effective strategy in patients with minor stroke or transient ischemic attack.

BACKGROUND: Patients with minor ischemic stroke or transient ischemic attacks (TIAs) are often treated with dual antiplatelet therapy regimens as part of secondary stroke prevention. Clopidogrel, an antiplatelet used in these regimens, is metabolized into its active form by the CYP2C19 enzyme. Patients with loss of function (LOF) mutations in CYP2C19 are at risk for poorer secondary outcomes when prescribed clopidogrel. AIMS: We aimed to determine the cost-effectiveness of three different treatment antiplatelet regimens in ischemic stroke populations with minor strokes or TIAs and how these treatment regimens are influenced by the LOF prevalence in the population. METHODS: Markov models were developed to look at the cost-effectiveness of empiric treatment with aspirin and clopidogrel versus empiric treatment with aspirin and ticagrelor, versus genotype-guided therapy for either 21 or 30 days. Effect ratios were obtained from the literature, and incidence rates and costs were obtained from the national data published by the Singapore Ministry of Health. The primary endpoints were the incremental cost-effectiveness ratios (ICERs). RESULTS: Empiric treatment with aspirin and ticagrelor was the most cost-effective treatment. Genotype-guided therapy was more cost-effective than empiric aspirin and clopidogrel if the LOF was above 48%. Empiric ticagrelor and aspirin was cost saving when compared to genotype-guided therapy. Results in models of dual antiplatelet therapy for 30 days were similar. CONCLUSION: This study suggests that in patients with minor stroke and TIA planned for dual antiplatelet regimens, empiric ticagrelor and aspirin is the most cost-effective treatment regimen. If ticagrelor is not available, genotype-guided therapy is the most cost-effective treatment regimen if the LOF prevalence in the population is more than 48%.

Long-term Cardiovascular, Cerebrovascular, and Other Thrombotic Complications in COVID-19 Survivors: A Retrospective Cohort Study.

BACKGROUND: Growing evidence suggests that some coronavirus disease 2019 (COVID-19) survivors experience a wide range of long-term postacute sequelae. We examined the postacute risk and burden of new-incident cardiovascular, cerebrovascular, and other thrombotic complications after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in a highly vaccinated multiethnic Southeast Asian population, during Delta predominance. METHODS: This cohort study used national testing and healthcare claims databases in Singapore to build a cohort of individuals who had a positive SARS-CoV-2 test between 1 September and 30 November 2021 when Delta predominated community transmission. Concurrently, we constructed a test-negative control group by enrolling individuals between 13 April 2020 and 31 December 2022 with no evidence of SARS-CoV-2 infection. Participants in both groups were followed up for a median of 300 days. We estimated risks of new-incident cardiovascular, cerebrovascular, and other thrombotic complications using doubly robust competing-risks survival analysis. Risks were reported using 2 measures: hazard ratio (HR) and excess burden (EB) with 95% confidence intervals. RESULTS: We included 106 012 infected cases and 1 684 085 test-negative controls. Compared with the control group, individuals with COVID-19 exhibited increased risk (HR, 1.157 [1.069-1.252]) and excess burden (EB, 0.70 [.53-.88]) of new-incident cardiovascular and cerebrovascular complications. Risks decreased in a graded fashion for fully vaccinated (HR, 1.11 [1.02-1.22]) and boosted (HR, 1.10 [.92-1.32]) individuals. Conversely, risks and burdens of subsequent cardiovascular/cerebrovascular complications increased for hospitalized and severe COVID-19 cases (compared to nonhospitalized cases). CONCLUSIONS: Increased risks and excess burdens of new-incident cardiovascular/cerebrovascular complications were reported among infected individuals; risks can be attenuated with vaccination and boosting.

Long-term neuropsychiatric sequelae of Delta versus Omicron SARS-CoV-2 infection.

OBJECTIVES: Studies have reported increased rates of long-term neuropsychiatric sequelae after SARS-CoV-2 infection using electronic health-record (EHR) data; however, the majority were conducted before Omicron and booster rollout. We estimated the long-term risks and excess burdens of pre-specified new-incident neuropsychiatric diagnoses after Delta versus Omicron BA.1/2 infection in a highly-vaccinated and boosted cohort of adult Singaporeans. METHODS: The national SARS-CoV-2 testing registry was used to construct cohorts of Singaporean adults infected during periods of Delta and Omicron BA.1/2 predominance and a contemporaneous test-negative control group. New-incident neuropsychiatric diagnoses recorded in the national health care claims database were identified up to 300 days postinfection. Risks and excess burden were estimated using a doubly robust competing-risks survival analysis. RESULTS: 104 179 and 375 903 infected cases were assigned to Delta and Omicron cohorts and compared against test-negative controls (Delta: N = 666 575 and Omicron: N = 619 379). Elevated risk of cognition or memory disorders was consistently reported across Omicron (Adjusted hazards ratio [aHR], 1.24; 95% CI, 1.12-1.38) and Delta cohorts (aHR, 1.63; 95% CI, 1.39-1.92). Delta-variant infection was associated with an increased risk of anosmia or dysgeusia (aHR, 4.53; 95% CI, 2.78-7.41) and psychosis (aHR, 1.65; 95% CI, 1.22-2.22). By contrast, Omicron-variant infection was associated with a risk of abnormal involuntary movements (aHR, 1.93; 95% CI, 1.32-2.83). Risks of neuropsychiatric sequelae predominantly accrued in hospitalized individuals. DISCUSSIONS: A modestly increased risk of cognition and memory disorders at 300 days after SARS-CoV-2 infection was observed among adult Singaporeans infected during the Delta/Omicron BA.1/2 transmission. There was no overall increased risk of neuropsychiatric sequelae observed across other domains. Variant-specific differences were also observed in individual neuropsychiatric sequelae, including an elevated risk of anosmia or dysgeusia after Delta-variant infection.