Improving anticoagulation in sub‐Saharan Africa: What are the challenges and how can we overcome them?

Mouton, Johannes P.; Blockman, Marc; Sekaggya-Wiltshire, Christine; Semakula, Jerome Roy; Waitt, Catriona; Pirmohamed, Munir; Cohen, Karen

doi:10.1111/bcp.14768

Cited by 16 publications

(13 citation statements)

References 105 publications

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“…absence of specialty anticoagulation clinics/services; lack of a multidisciplinary team in managing anticoagulation service in health facilities [ 2 ]. Application of evidence-based strategies should be settled, like implementing ‘warfarin care bundles’ that include process- and patient-centered activities [ 64 ], employing interventions that improve INR control [ 41 , 65 ], decentralization of anticoagulation services, setting up of anticoagulation clinics, improving access to warfarin, improving access to laboratory testing and/or scaling up point-of-care INR testing, task-shifting of anticoagulation care to mid-level health care workers, staff training, and implementing locally validated dose initiation and dose adjustment algorithms [ 23 ].…”

Section: Discussionmentioning

confidence: 99%

Anticoagulation control, outcomes, and associated factors in long-term-care patients receiving warfarin in Africa: a systematic review

et al. 2022

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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.

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Section: Discussionmentioning

confidence: 99%

Anticoagulation control, outcomes, and associated factors in long-term-care patients receiving warfarin in Africa: a systematic review

et al. 2022

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“…For example, in previous work we have conducted in sub-Saharan Africa (South Africa and Uganda), we observed that fixed-dose initiation was associated with a median time in therapeutic range (TTR) of 41% ( Semakula et al, 2020 ), which is much lower than that observed in an European (Sweden and United Kingdom) cohort (mean TTR 60%) ( Pirmohamed et al, 2013 ). Implementing a pharmacogenomic-dosing algorithm in the European cohort increased the mean TTR to 67% ( Pirmohamed et al, 2013 ), which makes the anticoagulation quality gap with sub-Saharan Africa even wider as there is no validated pharmacogenomic dosing algorithm in this region at the moment ( Mouton et al, 2021 ). Moreover, Europe which is wealthier than sub-Saharan Africa is able to afford the more costly new direct oral anticoagulants (DOACs), whereas sub-Saharan Africa’s choices are mainly limited to warfarin due to its low cost ( Semakula et al, 2021 ).…”

Section: Future Directions In Warfarin Pharmacogenomic Researchmentioning

confidence: 99%

Ethnic Diversity and Warfarin Pharmacogenomics

Asiimwe

Pirmohamed

2022

Front. Pharmacol.

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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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“…Warfarin is used widely in Africa, and a systematic review of genetic factors affecting warfarin dosing in Africans has recently been completed. 9,10 This shows the complexity of factors affecting dosing, with these factors now being investigated further in Uganda and South Africa (War-PATH http://warpath.info/) to develop specific clinical and genetic dosing algorithms in the longer term.…”

Section: Global Pharmacogenomics and Challenges To Implementation Worldwidementioning

confidence: 99%

Pharmacogenomics spotlight commentary: From the United Kingdom to global populations

Magavern

Daly

Gilchrist

et al. 2021

Brit J Clinical Pharma

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Improving anticoagulation in sub‐Saharan Africa: What are the challenges and how can we overcome them?

Cited by 16 publications

References 105 publications

Anticoagulation control, outcomes, and associated factors in long-term-care patients receiving warfarin in Africa: a systematic review

Anticoagulation control, outcomes, and associated factors in long-term-care patients receiving warfarin in Africa: a systematic review

Ethnic Diversity and Warfarin Pharmacogenomics

Pharmacogenomics spotlight commentary: From the United Kingdom to global populations

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