Applying narrative medicine to prepare empathetic healthcare providers in undergraduate pharmacy education in Singapore: a mixed methods study.

BACKGROUND: Narrative medicine demonstrated positive impact on empathy in medicine and nursing students. However, this pedagogical approach had not been evaluated in pharmacy education. This study sought to apply and evaluate the narrative medicine approach in extending empathy in Asian undergraduate pharmacy students. METHODS: Narrative medicine was applied through workshops which used narratives of people with different experiences and perspectives. First-year undergraduate pharmacy students who volunteered and attended these workshops formed the intervention group (N = 31) and the remaining first-year cohort formed the control group (N = 112). A sequential explanatory mixed methods approach was adopted in which quantitative methods were first used to measure impact on pharmacy students' empathy using the Jefferson Scale of Empathy- Health Professions Student (JSE-HPS), and qualitative methods (i.e. group interviews) were then used to assess pharmacy students' emotional responses to narratives, and the perspectives of pharmacy students and faculty of this pedagogical approach. RESULTS: There was no difference in JSE-HPS scores between intervention and control groups across baseline (i.e. upon matriculation), pre-intervention, and post-intervention timepoints. Pharmacy students in the intervention group had lower scores in Factor 3 ("Standing in People's Shoes") following the intervention. Five themes, guided by internal and external factors in cognition, emerged from the Group Interviews: (1) incongruence between students' motivation and faculty's perception, (2) learning context, (3) academic context, (4) cognitive system, and (5) affective system. Themes 1, 4 and 5 referred to internal factors such as students' motivation, perceived learnings, and feelings. Themes 2 and 3 referred to external factors including workshop materials, activities, content, and facilitation. CONCLUSION: This study is the first to demonstrate that pharmacy students engaged with the narrative medicine approach as narratives elicited emotional responses, exposed them to diverse perspectives, and deepened their appreciation of the importance of empathy and complexities of understanding patients' perspectives. Scaffolded educational interventions using narratives and real-life patient encounters, alongside longitudinal measurements of empathy, are necessary to bring about meaningful and sustained improvements in empathy.

Effects of Medications on Heat Loss Capacity in Chronic Disease Patients: Health Implications Amidst Global Warming.

Pharmacological agents used to treat or manage diseases can modify the level of heat strain experienced by chronically ill and elderly patients via different mechanistic pathways. Human thermoregulation is a crucial homeostatic process that maintains body temperature within a narrow range during heat stress through dry (i.e., increasing skin blood flow) and evaporative (i.e., sweating) heat loss, as well as active inhibition of thermogenesis, which is crucial to avoid overheating. Medications can independently and synergistically interact with aging and chronic disease to alter homeostatic responses to rising body temperature during heat stress. This review focuses on the physiologic changes, with specific emphasis on thermolytic processes, associated with medication use during heat stress. The review begins by providing readers with a background of the global chronic disease burden. Human thermoregulation and aging effects are then summarized to give an understanding of the unique physiologic changes faced by older adults. The effects of common chronic diseases on temperature regulation are outlined in the main sections. Physiologic impacts of common medications used to treat these diseases are reviewed in detail, with emphasis on the mechanisms by which these medications alter thermolysis during heat stress. The review concludes by providing perspectives on the need to understand the effects of medication use in hot environments, as well as a summary table of all clinical considerations and research needs of the medications included in this review. SIGNIFICANCE STATEMENT: Long-term medications modulate thermoregulatory function, resulting in excess physiological strain and predisposing patients to adverse health outcomes during prolonged exposures to extreme heat during rest and physical work (e.g., exercise). Understanding the medication-specific mechanisms of altered thermoregulation has importance in both clinical and research settings, paving the way for work toward refining current medication prescription recommendations and formulating mitigation strategies for adverse drug effects in the heat in chronically ill patients.

Simvastatin, but Not Atorvastatin, Is Associated with Higher Peak Rivaroxaban Serum Levels and Bleeding: an Asian Cohort Study from Singapore.

AIMS: This study attempts to identify predictors associated with bleeding and stroke and systemic embolism (SSE) in Singaporean Asians taking rivaroxaban and apixaban. METHODS: A total of 134 Singaporean patients on either rivaroxaban or apixaban for non-valvular atrial fibrillation were included for this study. Baseline characteristics were recorded at recruitment while bleeding and SSE events were recorded during a 1-year follow-up. Peak and trough drug plasma concentrations were collected based on the dosing interval and pharmacokinetics of the drugs and quantified using high performance liquid chromatography. Characteristics of patients with or without bleeds were compared using relevant statistical tests. Multivariable regression that included covariates with p < 0.1 from an initial univariable regression was performed to analyse predictors that resulted in higher risk of bleeding in patients. RESULTS: Median creatinine clearance (CrCl) was significantly lower in patients on rivaroxaban who experienced bleeds as compared to patients who did not experience bleeds (61.5 vs 70.8 mL/min, p = 0.047), while concomitant simvastatin use was found to be independently associated with a sixfold increased risk of bleeding (adjusted OR = 6.14 (95% CI: 1.18-31.97), p = 0.031) for rivaroxaban after controlling for body mass index, CrCl and having experienced a previous SSE. CONCLUSION: Our findings suggest that concomitant use of simvastatin with rivaroxaban may be associated with bleeding events in an Asian cohort. Further studies using physiologically based pharmacokinetic modelling are required to investigate the drug-drug interactions between these drugs.

The clinical impact of anti-hypertensive treatment drug-gene pairs in the asian population: a systematic review of publications in the past decade.

Pharmacogenetics play an important role in determining the anti-hypertensive effects of blood pressure-lowering medications and have the potential to improve future patient care. Current literature on the topic, however, has a heavy focus on Caucasians and may not be generalisable to the Asian populations. Therefore, we have conducted this systematic review to summarise and evaluate the literature of the past decade. PubMed, Embase, and the Cochrane Register of Controlled Trials were searched for relevant studies from 1 January 2011 to 23 July 2021. The outcome of interest was the response to anti-hypertensive treatment in Asians according to each genetic polymorphism. A total of 26 studies with a total of 8837 patients were included in our review, covering five classes of anti-hypertensive agents-namely, angiotensin-converting enzyme inhibitors (ACEI), angiotensin II receptor blockers (ARB), beta-blockers (BB), calcium channel blockers (CCB), and thiazide-like diuretics. Response to ACEI therapy was most susceptible to genotypic variations, while the efficacy of ARB and CCB were affected by pharmacogenetic differences to varying extent. For BB, only variations in the ADRB1 genotype significantly affects therapeutic response, while the therapeutic efficacy of thiazide-like diuretics was correlated with genotypic variations in the REN and ACE. This systematic review evaluated the impact of pharmacogenetic variations on the therapeutic efficacy of anti-hypertensive treatment in Asians and has described numerous drug-gene pairs that are potentially clinically important. Future prospective studies with larger sample sizes and longer follow-up periods are needed to better elucidate the impact of these drug-gene pairs.

Applying the OMOP Common Data Model to Facilitate Benefit-Risk Assessments of Medicinal Products Using Real-World Data from Singapore and South Korea.

OBJECTIVES: The aim of this study was to characterize the benefits of converting Electronic Medical Records (EMRs) to a common data model (CDM) and to assess the potential of CDM-converted data to rapidly generate insights for benefit-risk assessments in post-market regulatory evaluation and decisions. METHODS: EMRs from January 2013 to December 2016 were mapped onto the Observational Medical Outcomes Partnership-CDM (OMOP-CDM) schema. Vocabulary mappings were applied to convert source data values into OMOP-CDM-endorsed terminologies. Existing analytic codes used in a prior OMOP-CDM drug utilization study were modified to conduct an illustrative analysis of oral anticoagulants used for atrial fibrillation in Singapore and South Korea, resembling a typical benefit-risk assessment. A novel visualization is proposed to represent the comparative effectiveness, safety and utilization of the drugs. RESULTS: Over 90% of records were mapped onto the OMOP-CDM. The CDM data structures and analytic code templates simplified the querying of data for the analysis. In total, 2,419 patients from Singapore and South Korea fulfilled the study criteria, the majority of whom were warfarin users. After 3 months of follow-up, differences in cumulative incidence of bleeding and thromboembolic events were observable via the proposed visualization, surfacing insights as to the agent of preference in a given clinical setting, which may meaningfully inform regulatory decision-making. CONCLUSIONS: While the structure of the OMOP-CDM and its accessory tools facilitate real-world data analysis, extending them to fulfil regulatory analytic purposes in the post-market setting, such as benefit-risk assessments, may require layering on additional analytic tools and visualization techniques.

2021 Asian Pacific Society of Cardiology Consensus Recommendations on the Use of P2Y12 Receptor Antagonists in the Asia-Pacific Region: Special Populations.

Advanced age, diabetes, and chronic kidney disease not only increase the risk for ischaemic events in chronic coronary syndromes (CCS) but also confer a high bleeding risk during antiplatelet therapy. These special populations may warrant modification of therapy, especially among Asians, who have displayed characteristics that are clinically distinct from Western patients. Previous guidance has been provided regarding the classification of high-risk CCS and the use of newer-generation P2Y12 inhibitors (i.e. ticagrelor and prasugrel) after acute coronary syndromes (ACS) in Asia. The authors summarise evidence on the use of these P2Y12 inhibitors during the transition from ACS to CCS and among special populations. Specifically, they present recommendations on the roles of standard dual antiplatelet therapy, shortened dual antiplatelet therapy and single antiplatelet therapy among patients with coronary artery disease, who are either transitioning from ACS to CCS; elderly; or with chronic kidney disease, diabetes, multivessel coronary artery disease and bleeding events during therapy.

Widely heterogeneous humoral and cellular immunity after mild SARS-CoV-2 infection in a homogeneous population of healthy young men.

BACKGROUND: We studied humoral and cellular responses against SARS-CoV-2 longitudinally in a homogeneous population of healthy young/middle-aged men of South Asian ethnicity with mild COVID-19. METHODS: In total, we recruited 994 men (median age: 34 years) post-COVID-19 diagnosis. Repeated cross-sectional surveys were conducted between May 2020 and January 2021 at six time points - day 28 (n = 327), day 80 (n = 202), day 105 (n = 294), day 140 (n = 172), day 180 (n = 758), and day 280 (n = 311). Three commercial assays were used to detect anti-nucleoprotein (NP) and neutralizing antibodies. T cell response specific for Spike, Membrane and NP SARS-CoV-2 proteins was tested in 85 patients at day 105, 180, and 280. RESULTS: All serological tests displayed different kinetics of progressive antibody reduction while the frequency of T cells specific for different structural SARS-CoV-2 proteins was stable over time. Both showed a marked heterogeneity of magnitude among the studied cohort. Comparatively, cellular responses lasted longer than humoral responses and were still detectable nine months after infection in the individuals who lost antibody detection. Correlation between T cell frequencies and all antibodies was lost over time. CONCLUSION: Humoral and cellular immunity against SARS-CoV-2 is induced with differing kinetics of persistence in those with mild disease. The magnitude of T cells and antibodies is highly heterogeneous in a homogeneous study population. These observations have implications for COVID-19 surveillance, vaccination strategies, and post-pandemic planning.

Results of an international crowdsourcing survey on the treatment of non-ST segment elevation ACS patients at high-bleeding risk undergoing percutaneous intervention.

AIMS: Choosing an antiplatelet strategy in patients with non-ST segment elevation acute coronary syndrome (NSTE-ACS) at high bleeding risk (HBR), undergoing post-percutaneous coronary intervention (PCI), is complex. We used a unique open-source approach (crowdsourcing) to document if practices varied across a small, global cross-section of antiplatelet prescribers in the post-PCI setting. METHODS AND RESULTS: Five-hundred and fifty-nine professionals from 70 countries (the 'crowd') completed questionnaires containing single- or multi-option and free form questions regarding antiplatelet clinical practice in post-PCI NSTE-ACS patients at HBR. A threshold of 75% defined 'agreement'. There was strong agreement favouring monotherapy with either aspirin or a P2Y12 inhibitor following initial DAPT, within the first year (94%). No agreement was reached on the optimal duration of DAPT or choice of monotherapy: responses were in equipoise for shorter (≤3 months, 51%) or longer (≥6 months, 46%) duration, and monotherapy choice (45% aspirin; 53% P2Y12 inhibitor). Most respondents stated use of guideline-directed tools to assess risk, although clinical judgement was preferred by 32% for assessing bleeding risk and by 46% for thrombotic risk. CONCLUSION: The crowdsourcing methodology showed potential as a tool to assess current practice and variation on a global scale and to achieve a broad demographic representation. These preliminary results indicate a high degree of variation with respect to duration of DAPT, monotherapy drug of choice following DAPT and how thrombotic and bleeding risk are assessed. Further investigations should concentrate on interrogating practice variation between key demographic groups.

2020 Asian Pacific Society of Cardiology Consensus Recommendations on the Use of P2Y12 Receptor Antagonists in the Asia-Pacific Region.

The unique characteristics of patients with acute coronary syndrome in the Asia-Pacific region mean that international guidelines on the use of dual antiplatelet therapy (DAPT) cannot be routinely applied to these populations. Newer generation P2Y12 inhibitors (i.e. ticagrelor and prasugrel) have demonstrated improved clinical outcomes compared with clopidogrel. However, low numbers of Asian patients participated in pivotal studies and few regional studies comparing DAPTs have been conducted. This article aims to summarise current evidence on the use of newer generation P2Y12 inhibitors in Asian patients with acute coronary syndrome and provide recommendations to assist clinicians, especially cardiologists, in selecting a DAPT regimen. Guidance is provided on the management of ischaemic and bleeding risks, including duration of therapy, switching strategies and the management of patients with ST-elevation and non-ST-elevation MI or those requiring surgery. In particular, the need for an individualised DAPT regimen and considerations relating to switching, de-escalating, stopping or continuing DAPT beyond 12 months are discussed.

Cost-effectiveness of CYP2C19-guided antiplatelet therapy for acute coronary syndromes in Singapore.

We evaluated the cost-effectiveness of a genotype-guided strategy among patients with acute coronary syndromes using a decision-tree model based on the Singapore healthcare payer's perspective over a 1-year time horizon. Three dual antiplatelet strategies were considered: universal clopidogrel, genotype-guided, and universal ticagrelor. The prevalence of loss-of-function alleles was assumed to be 61.7% and model inputs were identified from the literature. Our primary outcome of interest was incremental cost-effectiveness ratio (ICER) compared to universal clopidogrel. Both genotype-guided (72,158 SGD/QALY) and universal ticagrelor (82,269 SGD/QALY) were considered cost-effective based on a willingness-to-pay (WTP) threshold of SGD 88,991. In our secondary analysis, the ICER for universal ticagrelor was 114,998 SGD/QALY when genotype-guided was taken as a reference. Probabilistic sensitivity analysis revealed that genotype-guided was the most cost-effective strategy when the WTP threshold was between SGD 70,000 to 100,000. Until more data are available, our study suggests that funding for a once-off CYP2C19 testing merits a consideration over 1 year of universal ticagrelor.

Patients' and Caregivers' Attitudes Toward Deprescribing in Singapore.

BACKGROUND: Knowledge of decision-making preference of patients and caregivers is needed to facilitate deprescribing. This study aimed to assess the perspectives of caregivers and older adults towards deprescribing in an Asian population. Secondary objectives were to identify and compare characteristics associated with these attitudes and beliefs. METHOD: A cross-sectional survey of two groups of participants was conducted using the Revised Patients' Attitudes Towards Deprescribing questionnaire. Descriptive results were reported for participants' characteristics and questionnaire responses from four factors (belief in medication inappropriateness, medication burden, concerns about stopping, and involvement) and two global questions. Correlation between participant characteristics and their responses was analyzed. RESULTS: A total of 1,057 (615 older adults; 442 caregivers) participants were recruited from 10 institutions in Singapore. In which 511 (83.0%) older adults and 385 (87.1%) caregivers reported that they would be willing to stop one or more of their medications if their doctor said it was possible, especially among older adults recruited from acute-care hospitals (85.3%) compared with older adults in community pharmacies (73.6%). Individuals who take more than five medications and those with higher education were correlated with greater agreement in inappropriateness and involvement, respectively. CONCLUSIONS: Clinicians should consider discussing deprescribing with older adults and caregivers in their regular clinical practice, especially when polypharmacy is present. Further research is needed into how to engage older adults and caregivers in shared decision making based on their attitudes toward deprescribing.

Cost Effectiveness of Genotype-Guided Antiplatelet Therapy in Asian Ischemic Stroke Patients: Ticagrelor as an Alternative to Clopidogrel in Patients with CYP2C19 Loss of Function Mutations.

BACKGROUND: Patients with ischemic stroke are often treated with clopidogrel monotherapy as part of secondary stroke prevention. The prevalence of loss of function (LOF) mutations in the CYP2C19 gene is higher in Asians than in Western populations. Patients with loss of function (LOF) mutations are at risk for poorer secondary outcomes when prescribed clopidogrel. OBJECTIVE: We aimed to determine the cost effectiveness of genotype-guided antiplatelet therapy in an Asian population with the aim of prescribing ticagrelor as an alternative to patients with LOF mutations. METHODS: Markov models were developed to look at the cost effectiveness of genetic testing of CYP2C19, with patients who screened positive for LOF alleles being switched to ticagrelor compared to universal clopidogrel treatment. 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. Lifetime costs and quality-adjusted life-years (QALYs) were calculated. The primary endpoints were the incremental cost-effectiveness ratios (ICERs). RESULTS: The prevalence of the LOF mutations was 61% in the population, with 65% of ethnic Chinese, 60% of ethnic Indian, and 53% of ethnic Malay patients having LOF mutations. Based on this prevalence, the overall ICER of genetic testing was S$33,839/QALY with ICERS of S$30,755/QALY, S$33,177/QALY, and S$41,470/QALY for Chinese, Indians, and Malays, respectively. CONCLUSION: This study suggests that it is cost effective to screen for LOF mutations in the CYP2C19 gene in ischemic stroke populations, with ticagrelor as a substitute for clopidogrel in those with LOF mutations.

Using Pharmacogenetic Testing to Tailor Warfarin Therapy: The Singapore Experience and What the Future Holds.

Genetic polymorphisms significantly affect individual responses to warfarin, contributing to unpredictability and challenges in managing anticoagulation. Although numerous studies have demonstrated that pharmacogenetic testing improves anticoagulation-related outcomes in the Caucasian population, its effect in the Asian population has not been well studied. This article discusses controversies surrounding tailoring warfarin therapy using pharmacogenetic testing and its role in clinical practice, with a focus on the Asian context. Using the Singapore experience as an example, the authors propose how pharmacogenetic testing can be a means to reduce dose titrations in select patient populations, and how it may be positioned as an enabler to reduce healthcare resources needed for anticoagulation management.

Measuring preferences for CYP2C19 genotyping in patients with acute coronary syndrome - a discrete choice experiment.

Aim: To evaluate the relative importance of CYP2C19 genotype-guided treatment attributes to patients. Patients & methods: A discrete choice experiment questionnaire was administered to 63 patients with acute coronary syndrome. Attributes examined in the discrete choice experiment questionnaire were: cost of genetic testing (S$50, S$100, S$200); cost of antiplatelet medication (S$100, S$500, S$1000); heart attack or stroke risk (5 in 100, 15 in 100, 25 in 100); bleeding risk (5 in 100, 15 in 100, 25 in 100); doctor's recommendation (yes, neutral). Mixed logit model was used for analysis. Results & conclusion: All attributes were important in patients' decision-making. Most displayed strong preference for doctor's recommendation and reduced heart attack or stroke risk. Genotyping was chosen by 63.5% of the patients.

Perspective on CYP2C19 genotyping test among patients with acute coronary syndrome - a qualitative study.

Aim: Identify factors patients consider regarding CYP2C19 genotyping test to guide choice of antiplatelet therapy. Patients & methods: Patient's perception and attitude toward use of CYP2C19 genotyping test was gathered according to an interview guide. Thematic analysis was conducted. Results: A total of 14 patients were interviewed. The main factors found to influence uptake of CYP2C19 genotyping test are, convenience of genotyping test (n = 4), physician's recommendation (n = 11), prior explanation of genetic testing by medical personnel (n = 5) and inclination toward clopidogrel, with three sub-factors; less frequent dosing (n = 3), lower cost (n = 7) and lower risk of bleeding (n = 9). Conclusion: This study provided the information needed to develop a discrete choice experiment to empirically quantify patients' preference and willingness to pay for genetic testing and to simulate uptake.

CYP2C19 phenotype in South-East Asian Acute Coronary Syndrome patients and impact on major adverse cardiovascular events.

WHAT IS KNOWN AND OBJECTIVE: Several Caucasian cohort studies have associated at least one loss-of-function CYP2C19 on Clopidogrel (LoF-Clopidogrel) with major adverse cardiovascular events (MACE), and only a couple have used Clinical Pharmacogenetics Implementation Consortium (CPIC® ) phenotype grouping to study the associations. We primarily aimed to study the impact of use of platelet reactivity testing to escalate antiplatelet therapy and secondarily to study the association of CPIC phenotype with MACE outcomes in South-East Asian Acute Coronary Syndrome (ACS) subjects. METHOD: A retrospective genotype study was performed on 238 percutaneous coronary intervention subjects, originally planned for escalation of antiplatelets using platelet reactivity testing. RESULTS AND DISCUSSION: There was no difference in MACE between the switched and unswitched groups; however, 'all bleeds' and 'clinically significant bleeds' (CSB) were statistically higher in the patients who were switched to prasugrel. The subgroup of patients who remained on clopidogrel (n = 199) were analysed using phenotype categories and MACE. Eleven percent (11.4%) of CYP2C19 poor metabolizers (PM) suffered MACE, compared with 1.3% of extensive metabolizers (EM). LoF-Clopidogrel patients are significantly more likely to experience MACE compared with non-LoF subjects (8.0% vs 5.4%, P: .041). WHAT IS NEW AND CONCLUSION: In our multivariate analysis, LoF-Clopidogrel, malay ethnicity, diabetics and use of proton pump inhibitors were independent predictors of MACE. There were numerically more bleeds in LoF subjects who were on prasugrel compared with Clopidogrel (23.5% vs 11%, P = .082). Our data corroborate with current findings on platelet reactivity testing, suggesting that the assay would not be sensitive enough to pick up sufficient 'at-risk' subjects as compared to the use of CYP2C19 genotyping.

Sex Differences in 1-Year Rehospitalization for Heart Failure and Myocardial Infarction After Primary Percutaneous Coronary Intervention.

It is unclear whether universal access to primary percutaneous coronary intervention (pPCI) may reduce sex differences in 1-year rehospitalization for heart failure (HF) and myocardial infarction (MI) after ST-elevation myocardial infarction (STEMI). We studied 7,597 consecutive STEMI patients (13.8% women, n = 1,045) who underwent pPCI from January 2007 to December 2013. Cox regression models adjusted for competing risk from death were used to assess sex differences in rehospitalization for HF and MI within 1 year from discharge. Compared with men, women were older (median age 67.6 vs 56.0 years, p < 0.001) with higher prevalence of co-morbidities and multivessel disease. Women had longer median door-to-balloon time (76 vs 66 minutes, p < 0.001) and were less likely to receive drug-eluting stents (19.5% vs 24.1%, p = 0.001). Of the medications prescribed at discharge, fewer women received aspirin (95.8% vs 97.6%, p = 0.002) and P2Y12 antagonists (97.6% vs 98.5%, p = 0.039), but there were no significant sex differences in other discharge medications. After adjusting for differences in baseline characteristics and treatment, sex differences in risk of rehospitalization for HF attenuated (hazard ratio [HR] 1.05, 95% confidence interval [CI] 0.79 to 1.40), but persisted for MI (HR 1.68, 95% CI 1.22 to 2.33), with greater disparity in patients aged ≥60 years (HR 1.83, 95% CI 1.18 to 2.85) than those aged <60 years (HR 1.45, 95% CI 0.84 to 2.50). In conclusion, in a setting of universal access to pPCI, the adjusted risk of 1-year rehospitalization for HF was similar in both sexes, but women had significantly higher adjusted risk of 1-year rehospitalization for MI, especially older women.

Efficacy and safety of reduced-dose non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation: a meta-analysis of randomized controlled trials.

AIMS: Non-vitamin K antagonist oral anticoagulants (NOACs) require dose reductions according to patient or clinical factors for patients with atrial fibrillation (AF). In this meta-analysis, we aimed to assess outcomes with reduced-dose NOACs when given as pre-specified in pivotal trials. METHODS AND RESULTS: Aggregated data abstracted from Phase III trials comparing NOACs with warfarin in patients with AF were assessed by treatment using risk ratios (RRs) and 95% confidence intervals (CIs) stratified by patient eligibility for NOAC dose reduction. Irrespective of treatments, annualized rates of stroke or systemic embolism and major bleeding were higher in patients eligible for reduced-dose NOACs than in those eligible for full-dose NOACs (2.70% vs. 1.60% and 4.35% vs. 2.87%, respectively). Effects of reduced-dose NOACs compared with warfarin in patients eligible for reduced-dose NOACs on stroke or systemic embolism [RR 0.84 (95% CI 0.69-1.03)] and on major bleeding [RR 0.70 (95% CI 0.50-0.97)] were consistent with those of full-dose NOACs relative to warfarin in those eligible for full-dose NOACs [RR 0.86 (95% CI 0.77-0.96) for stroke or systemic embolism and RR 0.87 (95% CI 0.70-1.08) for major bleeding; interaction P, 0.89 and 0.26, respectively]. In addition, NOACs were associated with reduced risks of haemorrhagic stroke, intracranial haemorrhage, fatal bleeding, and death regardless of patient eligibility for NOAC dose reduction (interaction P > 0.05 for each). CONCLUSIONS: Patients eligible for reduced-dose NOACs were at elevated risk of thromboembolic and haemorrhagic complications when treated with anticoagulants. NOACs, when appropriately dose-adjusted, had an improved benefit-harm profile compared with warfarin. Our findings highlight the importance of prescribing reduced-dose NOACs for indicated patient populations.