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Ingelman-Sundberg M, Pirmohamed M. Precision medicine in cardiovascular therapeutics: Evaluating the role of pharmacogenetic analysis prior to drug treatment. J Intern Med 2024; 295:583-598. [PMID: 38343077 DOI: 10.1111/joim.13772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Pharmacogenomics is the examination of how genetic variation influences drug metabolism and response, in terms of both efficacy and safety. In cardiovascular disease, patient-specific diplotypes determine phenotypes, thereby influencing the efficacy and safety of drug treatments, including statins, antiarrhythmics, anticoagulants and antiplatelets. Notably, polymorphisms in key genes, such as CYP2C9, CYP2C19, VKORC1 and SLCO1B1, significantly impact the outcomes of treatment with clopidogrel, warfarin and simvastatin. Furthermore, the CYP2C19 polymorphism influences the pharmacokinetics and safety of the novel hypertrophic cardiomyopathy inhibitor, mavacamten. In this review, we critically assess the clinical application of pharmacogenomics in cardiovascular disease and delineate present and future utilization of pharmacogenomics. This includes insights into identifying missing heritability, the integration of whole genome sequencing and the application of polygenic risk scores to enhance the precision of personalized drug therapy. Our discussion encompasses health economic analyses that underscore the cost benefits associated with pre-emptive genotyping for warfarin and clopidogrel treatments, albeit acknowledging the need for further research in this area. In summary, we contend that cardiovascular pharmacogenomic analyses are underpinned by a wealth of evidence, and implementation is already occurring for some of these gene-drug pairs, but as with any area of medicine, we need to continually gather more information to optimize the use of pharmacogenomics in clinical practice.
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Affiliation(s)
- Magnus Ingelman-Sundberg
- Department of Physiology and Pharmacology, Section of Pharmacogenetics, Biomedicum 5B, Karolinska Institutet, Stockholm, Sweden
| | - Munir Pirmohamed
- Wolfson Centre for Personalised Medicine, Department of Pharmacology and Therapeutics, University of Liverpool, Liverpool, UK
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Rekhtman D, Bermudez F, Vervoort D, Kaze L, Patton-Bolman C, Swain J. A Global Systematic Review of Open Heart Valvular Surgery in Resource-Limited Settings. Ann Thorac Surg 2024; 117:652-660. [PMID: 37898373 DOI: 10.1016/j.athoracsur.2023.10.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 09/24/2023] [Accepted: 10/09/2023] [Indexed: 10/30/2023]
Abstract
BACKGROUND Many obstacles challenge the establishment and expansion of cardiac surgery in low- and middle-income countries, despite the unmet cardiac surgical needs. One challenge has been providing adequate follow-up care to monitor anticoagulation, manage morbidity, and prevent mortality. This systematic review describes outcomes after valvular cardiac surgery and focuses on strategies for prolonged follow-up care in resource-constrained settings. METHODS Studies published between 2012 and 2022 were collected from Embase and the Cochrane Library. Article inclusion criteria were adolescent and adult patients, open heart valvular surgery, and analysis of at least 1 postoperative outcome at least 30 days postoperatively. Studies that focused on pediatric patients, pregnant patients, transcatheter procedures, in-hospital outcomes, and nonvalvular surgical procedures were excluded. Descriptive statistics were assessed, and articles were summarized after abstract screening, full-text review, and data extraction. RESULTS Sixty-seven relevant publications were identified after screening. The most commonly studied regions were Asia (46%), Africa (36%), and Latin America (9%). Rheumatic heart disease was the most commonly studied valvular disease (70%). Reported outcomes included mortality, surgical reintervention, and thrombotic events. Follow-up duration ranged from 30 days to 144 months; 11 studies reported a follow-up length of 12 months. CONCLUSIONS Addressing the unmet cardiac care needs requires a multifaceted approach that leverages telemedicine technology, enhances medical infrastructure, and aligns advocacy efforts. Learning from the cost-effective establishment of cardiac surgery in low- and middle-income countries, we can apply past innovations to foster sustainable cardiac surgical capacity.
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Affiliation(s)
- David Rekhtman
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
| | | | - Dominique Vervoort
- Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada
| | - Leslie Kaze
- Graduate School of Social and Political Science, University of Edinburgh, Edinburgh, United Kingdom; Team Heart, Inc, Kigali, Rwanda
| | | | - JaBaris Swain
- Team Heart, Inc, Kigali, Rwanda; Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
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Chikumbanje MM, Raza S, Barham L. The Budget Impact Analysis of Adopting Direct Oral Anticoagulants for Stroke Prevention in Nonvalvular Atrial Fibrillation Patients in Malawi. Value Health Reg Issues 2023; 37:53-61. [PMID: 37321105 DOI: 10.1016/j.vhri.2023.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 03/20/2023] [Accepted: 04/19/2023] [Indexed: 06/17/2023]
Abstract
OBJECTIVES This study aimed to estimate the budget impact of adopting direct oral anticoagulants (DOACs) for stroke prevention in patients with nonvalvular atrial fibrillation in Malawi after the inclusion of DOACs in the World Health Organization's essential medicine list. METHODS A model was developed in Microsoft Excel. An eligible population of 201 491 was adjusted with 0.05 % incidence rate and mortality rates yearly according to the treatments. The model estimated the implication of supplementing rivaroxaban or apixaban to the standard treatment mix (also the comparator), thus warfarin and aspirin. The current market share of 43% aspirin and 57% warfarin was adjusted proportionally with 10% DOAC uptake in the first year and 5% annually over the subsequent 4 years. Clinical events of stroke and major bleeding from the ROCKET-AF and ARISTOTLE trials were used because health outcome indicators affect resource utilization. The analysis was conducted solely from the Malawi Ministry of Health perspective and it considered direct costs over 5 years. The sensitivity analysis involved varying drug costs, population, and care costs from both public and private sectors. RESULTS The research suggests that despite potential savings of $6 644 141 to $6 930 812 in stroke care because of fewer stroke events, the total Ministry of Health healthcare budget (approximately $260 400 000) may increase by between $42 488 342 to $101 633 644 in 5 years because drug acquisition costs are greater than savings. CONCLUSIONS With a fixed budget and current DOACs prices, Malawi can consider using DOACs in patients at the highest risk while waiting for cheaper generic versions.
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Affiliation(s)
- Mirriam M Chikumbanje
- Faculty of Life Sciences and Education, Learna Ltd in Partnership with University of South Wales, Cardiff, Wales, UK.
| | - Syed Raza
- Faculty of Life Sciences and Education, Learna Ltd in Partnership with University of South Wales, Cardiff, Wales, UK
| | - Leela Barham
- Faculty of Life Sciences and Education, Learna Ltd in Partnership with University of South Wales, Cardiff, Wales, UK
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Jorgensen AL, Orrell C, Waitt C, Toh CH, Sekaggya-Wiltshire C, Hughes DA, Allen E, Okello E, Tatz G, Culeddu G, Asiimwe IG, Semakula JR, Mouton JP, Cohen K, Blockman M, Lamorde M, Pirmohamed M. A "Bundle of Care" to Improve Anticoagulation Control in Patients Receiving Warfarin in Uganda and South Africa: Protocol for an Implementation Study. JMIR Res Protoc 2023; 12:e46710. [PMID: 37467034 PMCID: PMC10398551 DOI: 10.2196/46710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 05/29/2023] [Accepted: 05/30/2023] [Indexed: 07/20/2023] Open
Abstract
BACKGROUND The quality of warfarin anticoagulation among Sub-Saharan African patients is suboptimal. This is due to several factors, including a lack of standardized dosing algorithms, difficulty in providing timely international normalized ratio (INR) results, a lack of patient feedback on their experiences with treatment, a lack of education on adherence, and inadequate knowledge and training of health care workers. Low quality of warfarin anticoagulation, expressed as time in therapeutic range (TTR), is associated with higher adverse event rates, including bleeding and thrombosis, and ultimately, increased morbidity and mortality. Processes and interventions that improve this situation are urgently needed. OBJECTIVE This study aims to evaluate the implementation of the "warfarin bundle," a package of interventions to improve the quality of anticoagulation and thereby clinical outcomes. The primary outcome for this study is TTR over the initial 3 months of warfarin therapy. METHODS Patients aged 18 years or older who are newly initiated on warfarin for venous thromboembolism, atrial fibrillation, or valvular heart disease will be enrolled and followed up for 3 months at clinics in Cape Town, South Africa, and Kampala, Uganda, where the warfarin bundle is implemented. A retrospective review of the clinical records of patients on warfarin treatment before implementation (controls) will be used for comparison. This study uses a mixed methods approach of the implementation of patient- and process-centered activities to improve the quality of anticoagulation. Patient-centered activities include the use of clinical dosing algorithms, adherence support, and root cause analysis, whereas process-centered activities include point-of-care INR testing, staff training, and patient education and training. We will assess the impact of these interventions by comparing the TTR and safety outcomes across the 2 groups, as well as the cost-effectiveness and acceptability of the package. RESULTS We started recruitment in June 2021 and stopped in August 2022, having recruited 167 participants. We obtained ethics approval from the University of Cape Town Faculty of Health Sciences Human Research Ethics Committee, the Provincial Health Research Committees in South Africa, the Joint Clinical Research Centre Institutional Review Board, Kampala, and the University of Liverpool Research Ethics Committee. As of February 2023, data cleaning and formal analysis are underway. We expect to publish the full results by December 2023. CONCLUSIONS We anticipate that the "bundle of care," which includes a clinical algorithm to guide individualized dosing of warfarin, will improve INR control and TTR of patients in Uganda and South Africa. We will use these findings to design a larger, multisite clinical trial across several Sub-Saharan African countries. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID) DERR1-10.2196/46710.
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Affiliation(s)
- Andrea L Jorgensen
- Department of Health Data Science, Institute of Population Health Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Catherine Orrell
- Desmond Tutu HIV Centre, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Catriona Waitt
- Infectious Diseases Institute, Makerere University College of Health Sciences, Kampala, Uganda
- Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Cheng-Hock Toh
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | | | - Dyfrig A Hughes
- Centre for Health Economics and Medicines Evaluation, School of Health Sciences, Bangor University, Bangor, United Kingdom
| | - Elizabeth Allen
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | | | - Gayle Tatz
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Giovanna Culeddu
- Centre for Health Economics and Medicines Evaluation, School of Health Sciences, Bangor University, Bangor, United Kingdom
| | - Innocent G Asiimwe
- The Wolfson Centre for Personalized Medicine, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Jerome Roy Semakula
- Infectious Diseases Institute, Makerere University College of Health Sciences, Kampala, Uganda
| | - Johannes P Mouton
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Karen Cohen
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Marc Blockman
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Mohammed Lamorde
- Infectious Diseases Institute, Makerere University College of Health Sciences, Kampala, Uganda
| | - Munir Pirmohamed
- The Wolfson Centre for Personalized Medicine, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
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Minja NW, Nakagaayi D, Aliku T, Zhang W, Ssinabulya I, Nabaale J, Amutuhaire W, de Loizaga SR, Ndagire E, Rwebembera J, Okello E, Kayima J. Cardiovascular diseases in Africa in the twenty-first century: Gaps and priorities going forward. Front Cardiovasc Med 2022; 9:1008335. [PMID: 36440012 PMCID: PMC9686438 DOI: 10.3389/fcvm.2022.1008335] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 10/24/2022] [Indexed: 11/11/2022] Open
Abstract
In 2015, the United Nations set important targets to reduce premature cardiovascular disease (CVD) deaths by 33% by 2030. Africa disproportionately bears the brunt of CVD burden and has one of the highest risks of dying from non-communicable diseases (NCDs) worldwide. There is currently an epidemiological transition on the continent, where NCDs is projected to outpace communicable diseases within the current decade. Unchecked increases in CVD risk factors have contributed to the growing burden of three major CVDs-hypertension, cardiomyopathies, and atherosclerotic diseases- leading to devastating rates of stroke and heart failure. The highest age standardized disability-adjusted life years (DALYs) due to hypertensive heart disease (HHD) were recorded in Africa. The contributory causes of heart failure are changing-whilst HHD and cardiomyopathies still dominate, ischemic heart disease is rapidly becoming a significant contributor, whilst rheumatic heart disease (RHD) has shown a gradual decline. In a continent where health systems are traditionally geared toward addressing communicable diseases, several gaps exist to adequately meet the growing demand imposed by CVDs. Among these, high-quality research to inform interventions, underfunded health systems with high out-of-pocket costs, limited accessibility and affordability of essential medicines, CVD preventive services, and skill shortages. Overall, the African continent progress toward a third reduction in premature mortality come 2030 is lagging behind. More can be done in the arena of effective policy implementation for risk factor reduction and CVD prevention, increasing health financing and focusing on strengthening primary health care services for prevention and treatment of CVDs, whilst ensuring availability and affordability of quality medicines. Further, investing in systematic country data collection and research outputs will improve the accuracy of the burden of disease data and inform policy adoption on interventions. This review summarizes the current CVD burden, important gaps in cardiovascular medicine in Africa, and further highlights priority areas where efforts could be intensified in the next decade with potential to improve the current rate of progress toward achieving a 33% reduction in CVD mortality.
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Affiliation(s)
- Neema W. Minja
- Rheumatic Heart Disease Research Collaborative, Uganda Heart Institute, Kampala, Uganda
- Kilimanjaro Clinical Research Institute (KCRI), Moshi, Tanzania
- Department of Global Health, University of Washington, Seattle, WA, United States
| | - Doreen Nakagaayi
- Department of Adult Cardiology, Uganda Heart Institute, Kampala, Uganda
- Heart Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Twalib Aliku
- Department of Pediatric Cardiology, Uganda Heart Institute, Kampala, Uganda
| | - Wanzhu Zhang
- Department of Adult Cardiology, Uganda Heart Institute, Kampala, Uganda
| | - Isaac Ssinabulya
- Department of Adult Cardiology, Uganda Heart Institute, Kampala, Uganda
- Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Juliet Nabaale
- Department of Adult Cardiology, Uganda Heart Institute, Kampala, Uganda
| | - Willington Amutuhaire
- Department of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Sarah R. de Loizaga
- Heart Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, United States
| | - Emma Ndagire
- Department of Pediatric Cardiology, Uganda Heart Institute, Kampala, Uganda
| | | | - Emmy Okello
- Department of Adult Cardiology, Uganda Heart Institute, Kampala, Uganda
- Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - James Kayima
- Department of Adult Cardiology, Uganda Heart Institute, Kampala, Uganda
- Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
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Tadesse TA, Tegegne GT, Yadeta D, Chelkaba L, Fenta TG. Anticoagulation control, outcomes, and associated factors in long-term-care patients receiving warfarin in Africa: a systematic review. Thromb J 2022; 20:58. [PMID: 36192776 PMCID: PMC9528137 DOI: 10.1186/s12959-022-00416-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 09/21/2022] [Indexed: 11/26/2022] Open
Abstract
Background Oral anticoagulation therapy with warfarin requires frequent monitoring level of anticoagulation by the international normalized ratio (INR). In Africa, studies that explore anticoagulation control, treatment outcomes, and associated factors are reported in various ways in long-term patients receiving warfarin therapy to generate concrete scientific evidence. Methods The literature search was conducted in PubMed, Cochrane Library, African Journal of Online databases, Google Scholar, and Google. An advanced search strategy was computed to retrieve relevant studies related to anticoagulation control and outcomes. Duplication, title and abstract screening, and full-text assessment were conducted in Covidence software. Study quality was assessed using the Joanna Briggs Institute Critical appraisal quality assessment tool. The systematic review is registered in PROSPERO (CRD42021260772) and performed based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guideline. Results Out of 298 identified articles, 18 articles were eligible for the final review and analysis. The mean of 39.4 ± 8.4% time in therapeutic range (TTR) (29.4 to 57.3%), 36.7 ± 11.5% TTR (range 25.2–49.7%) and 46% TTR (43.5–48.5%) was computed from studies that determined TTR by Rosendaal, direct and cross-section-of-the-files methods, respectively. In this review, the lowest percentage of TTR was 13.7%, while the highest was 57.3%. The highest percentage of patients (32.25%) who had TTR ≥ 65% was reported in Tunisia, but the lowest percentages were in Namibia (10%, TTR ≥ 65%) and Kenya (10.4%, TTR ≥ 70%). Most of the included studies (11 out of 18) used Rosendaal’s method while the direct method was employed by three studies. Generally, 10.4–32.3% of study participants achieved desired optimal anticoagulation level. Regarding secondary outcomes, 1.6–7.5% and 0.006–59% of patients experienced thromboembolic complications and bleeding events, respectively. Having chronic comorbidities, taking more than two drugs, and presence of medications that potentially interact with warfarin, and patient-related factors (patients aged < 50 years old, female gender, lower education level, smoking history) were the frequently reported predictors of poor anticoagulation therapy. Conclusions Oral anticoagulation control was suboptimal in patients taking warfarin as evidenced by low TTR in Africa. Therefore, there is an urgent need for further improving oral anticoagulation management services. Supplementary Information The online version contains supplementary material available at 10.1186/s12959-022-00416-9.
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Affiliation(s)
- Tamrat Assefa Tadesse
- Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.,Department of Pharmaceutics and Social Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Gobezie Temesgen Tegegne
- Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Dejuma Yadeta
- Departmnt of Internal Medicine, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Legese Chelkaba
- Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Teferi Gedif Fenta
- Department of Pharmaceutics and Social Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
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Asiimwe IG, Blockman M, Cohen K, Cupido C, Hutchinson C, Jacobson B, Lamorde M, Morgan J, Mouton JP, Nakagaayi D, Okello E, Schapkaitz E, Sekaggya-Wiltshire C, Semakula JR, Waitt C, Zhang EJ, Jorgensen AL, Pirmohamed M. A genome-wide association study of plasma concentrations of warfarin enantiomers and metabolites in sub-Saharan black-African patients. Front Pharmacol 2022; 13:967082. [PMID: 36210801 PMCID: PMC9537548 DOI: 10.3389/fphar.2022.967082] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 08/23/2022] [Indexed: 11/26/2022] Open
Abstract
Diversity in pharmacogenomic studies is poor, especially in relation to the inclusion of black African patients. Lack of funding and difficulties in recruitment, together with the requirement for large sample sizes because of the extensive genetic diversity in Africa, are amongst the factors which have hampered pharmacogenomic studies in Africa. Warfarin is widely used in sub-Saharan Africa, but as in other populations, dosing is highly variable due to genetic and non-genetic factors. In order to identify genetic factors determining warfarin response variability, we have conducted a genome-wide association study (GWAS) of plasma concentrations of warfarin enantiomers/metabolites in sub-Saharan black-Africans. This overcomes the issue of non-adherence and may have greater sensitivity at genome-wide level, to identify pharmacokinetic gene variants than focusing on mean weekly dose, the usual end-point used in previous studies. Participants recruited at 12 outpatient sites in Uganda and South Africa on stable warfarin dose were genotyped using the Illumina Infinium H3Africa Consortium Array v2. Imputation was conducted using the 1,000 Genomes Project phase III reference panel. Warfarin/metabolite plasma concentrations were determined by high-performance liquid chromatography with tandem mass spectrometry. Multivariable linear regression was undertaken, with adjustment made for five non-genetic covariates and ten principal components of genetic ancestry. After quality control procedures, 548 participants and 17,268,054 SNPs were retained. CYP2C9*8, CYP2C9*9, CYP2C9*11, and the CYP2C cluster SNP rs12777823 passed the Bonferroni-adjusted replication significance threshold (p < 3.21E-04) for warfarin/metabolite ratios. In an exploratory GWAS analysis, 373 unique SNPs in 13 genes, including CYP2C9*8, passed the Bonferroni-adjusted genome-wide significance threshold (p < 3.846E-9), with 325 (87%, all located on chromosome 10) SNPs being associated with the S-warfarin/R-warfarin outcome (top SNP rs11188082, CYP2C19 intron variant, p = 1.55E-17). Approximately 69% of these SNPs were in linkage disequilibrium (r2 > 0.8) with CYP2C9*8 (n = 216) and rs12777823 (n = 8). Using a pharmacokinetic approach, we have shown that variants other than CYP2C9*2 and CYP2C9*3 are more important in sub-Saharan black-Africans, mainly due to the allele frequencies. In exploratory work, we conducted the first warfarin pharmacokinetics-related GWAS in sub-Saharan Africans and identified novel SNPs that will require external replication and functional characterization before they can be considered for inclusion in warfarin dosing algorithms.
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Affiliation(s)
- Innocent G. Asiimwe
- The Wolfson Centre for Personalized Medicine, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
- *Correspondence: Innocent G. Asiimwe, ; Munir Pirmohamed,
| | - Marc Blockman
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Karen Cohen
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Clint Cupido
- Victoria Hospital Internal Medicine Research Initiative, Victoria Hospital Wynberg and Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Claire Hutchinson
- The Wolfson Centre for Personalized Medicine, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Barry Jacobson
- Department of Molecular Medicine and Haematology, University of the Witwatersrand, Johannesburg, South Africa
| | - Mohammed Lamorde
- Infectious Diseases Institute, Makerere University College of Health Sciences, Kampala, Uganda
| | - Jennie Morgan
- Metro District Health Services, Western Cape Department of Health, Cape Town, South Africa
| | - Johannes P. Mouton
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | | | | | - Elise Schapkaitz
- Department of Molecular Medicine and Hematology, Charlotte Maxeke Johannesburg Academic Hospital National Health Laboratory System Complex and University of Witwatersrand, Johannesburg, South Africa
| | | | - Jerome R. Semakula
- Infectious Diseases Institute, Makerere University College of Health Sciences, Kampala, Uganda
| | - Catriona Waitt
- The Wolfson Centre for Personalized Medicine, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
- Infectious Diseases Institute, Makerere University College of Health Sciences, Kampala, Uganda
| | - Eunice J. Zhang
- The Wolfson Centre for Personalized Medicine, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Andrea L. Jorgensen
- Department of Health Data Science, Institute of Population Health Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Munir Pirmohamed
- The Wolfson Centre for Personalized Medicine, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
- *Correspondence: Innocent G. Asiimwe, ; Munir Pirmohamed,
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Asiimwe IG, Pirmohamed M. Ethnic Diversity and Warfarin Pharmacogenomics. Front Pharmacol 2022; 13:866058. [PMID: 35444556 PMCID: PMC9014219 DOI: 10.3389/fphar.2022.866058] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 03/14/2022] [Indexed: 12/23/2022] Open
Abstract
Warfarin has remained the most commonly prescribed vitamin K oral anticoagulant worldwide since its approval in 1954. Dosing challenges including having a narrow therapeutic window and a wide interpatient variability in dosing requirements have contributed to making it the most studied drug in terms of genotype-phenotype relationships. However, most of these studies have been conducted in Whites or Asians which means the current pharmacogenomics evidence-base does not reflect ethnic diversity. Due to differences in minor allele frequencies of key genetic variants, studies conducted in Whites/Asians may not be applicable to underrepresented populations such as Blacks, Hispanics/Latinos, American Indians/Alaska Natives and Native Hawaiians/other Pacific Islanders. This may exacerbate health inequalities when Whites/Asians have better anticoagulation profiles due to the existence of validated pharmacogenomic dosing algorithms which fail to perform similarly in the underrepresented populations. To examine the extent to which individual races/ethnicities are represented in the existing body of pharmacogenomic evidence, we review evidence pertaining to published pharmacogenomic dosing algorithms, including clinical utility studies, cost-effectiveness studies and clinical implementation guidelines that have been published in the warfarin field.
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Affiliation(s)
- Innocent G Asiimwe
- The Wolfson Centre for Personalized Medicine, MRC Centre for Drug Safety Science, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Munir Pirmohamed
- The Wolfson Centre for Personalized Medicine, MRC Centre for Drug Safety Science, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
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Asiimwe IG, Blockman M, Cohen K, Cupido C, Hutchinson C, Jacobson B, Lamorde M, Morgan J, Mouton JP, Nakagaayi D, Okello E, Schapkaitz E, Sekaggya-Wiltshire C, Semakula JR, Waitt C, Zhang EJ, Jorgensen AL, Pirmohamed M. Stable warfarin dose prediction in sub-Saharan African patients: A machine-learning approach and external validation of a clinical dose-initiation algorithm. CPT Pharmacometrics Syst Pharmacol 2022; 11:20-29. [PMID: 34889080 PMCID: PMC8752108 DOI: 10.1002/psp4.12740] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/24/2021] [Accepted: 10/27/2021] [Indexed: 12/11/2022] Open
Abstract
Warfarin remains the most widely prescribed oral anticoagulant in sub‐Saharan Africa. However, because of its narrow therapeutic index, dosing can be challenging. We have therefore (a) evaluated and compared the performance of 21 machine‐learning techniques in predicting stable warfarin dose in sub‐Saharan Black‐African patients and (b) externally validated a previously developed Warfarin Anticoagulation in Patients in Sub‐Saharan Africa (War‐PATH) clinical dose–initiation algorithm. The development cohort included 364 patients recruited from eight outpatient clinics and hospital departments in Uganda and South Africa (June 2018–July 2019). Validation was conducted using an external validation cohort (270 patients recruited from August 2019 to March 2020 in 12 outpatient clinics and hospital departments). Based on the mean absolute error (MAE; mean of absolute differences between the actual and predicted doses), random forest regression (12.07 mg/week; 95% confidence interval [CI], 10.39–13.76) was the best performing machine‐learning technique in the external validation cohort, whereas the worst performing technique was model trees (17.59 mg/week; 95% CI, 15.75–19.43). By comparison, the simple, commonly used regression technique (ordinary least squares) performed similarly to more complex supervised machine‐learning techniques and achieved an MAE of 13.01 mg/week (95% CI, 11.45–14.58). In summary, we have demonstrated that simpler regression techniques perform similarly to more complex supervised machine‐learning techniques. We have also externally validated our previously developed clinical dose–initiation algorithm, which is being prospectively tested for clinical utility.
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Affiliation(s)
- Innocent G Asiimwe
- Department of Pharmacology and Therapeutics, The Wolfson Centre for Personalized Medicine, Medical Research Council Centre for Drug Safety Science, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Marc Blockman
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Karen Cohen
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Clint Cupido
- Victoria Hospital Internal Medicine Research Initiative, Victoria Hospital Wynberg, Cape Town, South Africa.,Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Claire Hutchinson
- Department of Pharmacology and Therapeutics, The Wolfson Centre for Personalized Medicine, Medical Research Council Centre for Drug Safety Science, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Barry Jacobson
- Department of Molecular Medicine and Haematology, University of the Witwatersrand, Johannesburg, South Africa
| | - Mohammed Lamorde
- Infectious Diseases Institute, Makerere University College of Health Sciences, Kampala, Uganda
| | - Jennie Morgan
- Metro District Health Services, Western Cape Department of Health, Cape Town, South Africa
| | - Johannes P Mouton
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | | | | | - Elise Schapkaitz
- Department of Molecular Medicine and Hematology, Charlotte Maxeke Johannesburg Academic Hospital National Health Laboratory System Complex and University of Witwatersrand, Johannesburg, South Africa
| | | | - Jerome R Semakula
- Infectious Diseases Institute, Makerere University College of Health Sciences, Kampala, Uganda
| | - Catriona Waitt
- Department of Pharmacology and Therapeutics, The Wolfson Centre for Personalized Medicine, Medical Research Council Centre for Drug Safety Science, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK.,Infectious Diseases Institute, Makerere University College of Health Sciences, Kampala, Uganda
| | - Eunice J Zhang
- Department of Pharmacology and Therapeutics, The Wolfson Centre for Personalized Medicine, Medical Research Council Centre for Drug Safety Science, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Andrea L Jorgensen
- Department of Health Data Science, Institute of Population Health Sciences, University of Liverpool, Liverpool, UK
| | - Munir Pirmohamed
- Department of Pharmacology and Therapeutics, The Wolfson Centre for Personalized Medicine, Medical Research Council Centre for Drug Safety Science, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
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Dandara C, Ndadza A, Soko N. The importance of including African populations in pharmacogenetics studies of warfarin response. Pharmacogenomics 2021; 23:1-4. [PMID: 34821506 DOI: 10.2217/pgs-2021-0142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Tweetable abstract Warfarin will remain in use for a long time to come, thus inclusion of African populations in pharmacogenomics is essential to be able to identify all possible biomarkers that are potential predictors for warfarin drug response.
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Affiliation(s)
- Collet Dandara
- Department of Pathology & Institute of Infectious Diseases & Molecular Medicine, Pharmacogenomics & Drug Metabolism Research Group, Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa
| | - Arinao Ndadza
- Department of Pathology & Institute of Infectious Diseases & Molecular Medicine, Pharmacogenomics & Drug Metabolism Research Group, Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa
| | - Nyarai Soko
- Department of Pathology & Institute of Infectious Diseases & Molecular Medicine, Pharmacogenomics & Drug Metabolism Research Group, Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa
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11
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Mouton JP, Blockman M, Sekaggya-Wiltshire C, Semakula J, Waitt C, Pirmohamed M, Cohen K. Improving anticoagulation in sub-Saharan Africa: What are the challenges and how can we overcome them? Br J Clin Pharmacol 2021; 87:3056-3068. [PMID: 33586223 PMCID: PMC8359270 DOI: 10.1111/bcp.14768] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 01/04/2021] [Accepted: 02/05/2021] [Indexed: 12/12/2022] Open
Abstract
Patients in sub-Saharan Africa generally have poor anticoagulation control. We review the potential reasons for this poor control, as well as the potential solutions. Challenges include the affordability and centralisation of anticoagulation care, problems with access to medicines and international normalised ratio monitoring, the lack of locally validated standardized dosing protocols, and low levels of anticoagulation knowledge among healthcare workers and patients. Increasing numbers of patients will need anticoagulation in the future because of the increasing burden of noncommunicable disease in the region. We propose that locally developed "warfarin care bundles" which address multiple anticoagulation challenges in combination may be the most appropriate solution in this setting currently.
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Affiliation(s)
- Johannes P Mouton
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Marc Blockman
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | | | - Jerome Semakula
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Catriona Waitt
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda.,Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Munir Pirmohamed
- Wolfson Centre for Personalised Medicine, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Karen Cohen
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
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