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23 result(s) for "Blockman, Marc"
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A Mixed Methods, Cluster-Randomised Study Protocol to Design and Test WhatsApp Group-Based HIV Microlearning for Rural South African Healthcare Workers
Treatment of HIV in South Africa is informed by national guidelines, which are regularly updated. Ongoing training of healthcare workers is vital for optimal patient care, but is challenging, due to human, financial and infrastructural constraints. There is a need for innovative solutions to meet training and support needs. With 93.2% of South African adults using WhatsApp, it is an ideal platform for training, even in the most remote clinics. The primary aim of the study is to design, test and evaluate the effect of WhatsApp group-based HIV training on nurses’ and community health workers’ knowledge. The secondary aims are to assess uptake, acceptability, and feasibility of the intervention; and to explore and describe the changes in prescribing, comparing the intervention group to the control group. A pragmatic, mixed-methods, parallel-group cluster-randomised study design will be used. This paper details the design – and rationale behind it – of the study. A critical realist stance was chosen, with outcomes measured using questionnaires, pre- and post-intervention; WhatsApp group interaction; focus groups; and folder reviews. Inferential analysis will be conducted using Stata, descriptive analysis using Excel™ and qualitative data using template analysis with NVivo™. Rigor of the study will be ensured using relevant points from the CASP and COREQ checklists, considering the study’s theoretical underpinning, design and aims. Reporting will be guided by the CONSORT and SRQR guidelines.
Warfarin : better the devil you know
Long-term anticoagulation with warfarin is recommended for patients with atrial fibrillation (AF), valvular heart disease and pulmonary embolus, as these conditions significantly increase the risk for thromboembolic complications. 1 AF for example increases the risk for ischaemic stroke four- to five-fold. 1
A cross-sectional evaluation of five warfarin anticoagulation services in Uganda and South Africa
Warfarin is the most commonly prescribed oral anticoagulant in sub-Saharan Africa and requires ongoing monitoring. The burden of both infectious diseases and non-communicable diseases is high and medicines used to treat comorbidities may interact with warfarin. We describe service provision, patient characteristics, and anticoagulation control at selected anticoagulation clinics in Uganda and South Africa. We evaluated two outpatient anticoagulation services in Kampala, Uganda and three in Cape Town, South Africa between 1 January and 31 July 2018. We collected information from key staff members about the clinics' service provision and extracted demographic and clinical data from a sample of patients' clinic records. We calculated time in therapeutic range (TTR) over the most recent 3-month period using the Rosendaal interpolation method. We included three tertiary level, one secondary level and one primary level anticoagulation service, seeing between 30 and 800 patients per month. Care was rendered by nurses, medical officers, and specialists. All healthcare facilities had on-site pharmacies; laboratory INR testing was off-site at two. Three clinics used warfarin dose-adjustment protocols; these were not validated for local use. We reviewed 229 patient clinical records. Most common indications for warfarin were venous thrombo-embolism in 112/229 (49%), atrial fibrillation in 74/229 (32%) and valvular heart disease in 30/229 (13%). Patients were generally followed up monthly. HIV prevalence was 20% and 5% at Ugandan and South African clinics respectively. Cardiovascular comorbidity predominated. Furosemide, paracetamol, enalapril, simvastatin, and tramadol were the most common concomitant drugs. Anticoagulation control was poor at all included clinics with median TTR of 41% (interquartile range 14% to 69%). TTR was suboptimal at all included sites, despite frequent patient follow-up. Strategies to improve INR control in sub-Saharan patients taking warfarin are needed. Locally validated warfarin dosing algorithms in Uganda and South Africa may improve INR control.
Pharmacogenetics of Mycophenolic Acid in Patients of African Descent: Underrepresentation of African Data
Mycophenolic acid (MPA) is a potent antiproliferative immunosuppressive agent used to prevent organ transplant rejection and to treat various immune‐mediated diseases. MPA is the active metabolite formed from the biotransformation of the prodrugs mycophenolate mofetil (MMF) or enteric‐coated mycophenolate sodium (EC‐MPS). MPA exerts its therapeutic effects by inhibiting guanosine nucleotide synthesis in lymphocytes. Through this inhibition, cell and humoral immunity is suppressed, resulting in a reduction of cytotoxicity and inflammation. Systemic exposure to MPA is influenced by a complex pharmacokinetic pathway, which involves various drug‐metabolizing enzymes (DMEs) and transporters. Substantial interindividual variability exists in MPA exposure, efficacy, and adverse effects. Genetic polymorphisms in the genes encoding DMEs and transporters have been reported to influence this observed variability; however, evidence remains inconsistent and is largely derived from non‐African populations. African populations exhibit high levels of genetic diversity, and their underrepresentation in pharmacogenetic studies may hinder the identification of important variants influencing MPA disposition and clinical outcomes. This review evaluates the genes that have been reported to affect MPA exposure as well as highlights conflicting results on the role of these pharmacogenetic variants in different populations. The review highlights the lack of data on African populations and provides justification for their inclusion in the study of MPA pharmacogenetics. Study Highlights What is the current knowledge on the topic? Current knowledge shows that genetic variants in UGT enzymes, drug transporters, and IMPDH isoforms influence MPA exposure, toxicity, and treatment response. Most findings come from European and Asian cohorts, with African populations largely underrepresented despite a high disease burden. What question did this study address? Does pharmacogenetics play a role in MMF/MPA exposure and treatment outcomes in patients of African populations? What does this study add to our knowledge? This review highlights conflicting results in previous research, that there are gaps in ethnic‐specific data, and that there is a lack of inclusion of participants of African descent in MPA related pharmacogenetic research. How might this change clinical pharmacology or translational science? The lack of African‐specific pharmacogenetic research on MPA exposure and treatment outcomes limits the accuracy of European‐based dosing strategies in African populations, thereby underscoring the need for population‐specific pharmacogenetic research to guide safe and effective MMF use.
Safety Considerations in Cannabinoid-Based Medicine
Cannabinoids are a diverse class of chemical compounds that are increasingly recognized as potential therapeutic options for a range of conditions. While many studies and reviews of cannabinoids focus on efficacy, safety is much less well reported. Overall assessment of the safety of cannabinoid-based medicines is confounded by confusion with recreational cannabis use as well as different study designs, indications, dosing, and administration methods. However, clinical studies in registered products are increasingly available, and this article aims to discuss and clarify what is known regarding the safety profiles of cannabinoid-based medicines, focusing on the medical and clinical safety evidence and identifying areas for future research. The two most well-studied cannabinoids are Δ -tetrahydrocannabinol (THC), or its synthetic variants (dronabinol, nabilone), and cannabidiol (CBD). Across diverse indications, dizziness and fatigue are generally the most common adverse events experienced by patients receiving THC or combined THC and CBD. Patients receiving THC may experience adverse cognitive effects and impairment in psychomotor skills, with implications for driving and some occupations, while CBD may help to lower the psychotropic effects of THC when used in combination. Studies on dependency and addiction in a medical context are limited, but have shown inconsistent findings regarding misuse potential. Generally, the recommended route of administration is oral ingestion, as smoking medicinal cannabinoid products potentially releases mutagenic and carcinogenic by-products. There are several potential drug-drug interactions and contraindications for cannabinoid-based medicines, which physicians should account for when making prescribing decisions. The available evidence shows that, as with any other class of pharmaceuticals, cannabinoid-based medicines are associated with safety risks which should be assessed in the context of potential therapeutic benefits. Each patient should be assessed on an individual basis and physicians must rely on informed, evidence-based decision-making when determining whether a cannabinoid-based medicine could be an appropriate treatment option.
Management of Type 2 Diabetes Mellitus and Kidney Failure in People with HIV-Infection in Africa: Current Status and a Call to Action
There is an increasing global burden of diabetes mellitus (DM) and chronic kidney disease (CKD), coupled with a high burden of people with HIV (PWH). Due to an increased lifespan on ART, PWH are now at risk of developing non- communicable diseases, including DM. Africa has the greatest burden of HIV infection and will experience the greatest increase in prevalence of DM over the next two decades. In addition, there is a rising number of people with CKD and progression to kidney failure. Therefore, there is an urgent need for the early identification and management of all 3 diseases to prevent disease progression and complications. This is particularly important in Africa for people with CKD where there is restricted or no access to dialysis and/or transplantation. This review focuses on the epidemiology and pathophysiology of the interaction between HIV infection and DM and the impact that these diseases have on the development and progression of CKD. Finally, it also aims to review the data on the management, which stems from the growing burden of all three diseases. Keywords: chronic kidney disease, renal replacement therapy, antiretroviral therapy, Diabetes mellitus
A genome-wide association study of plasma concentrations of warfarin enantiomers and metabolites in sub-Saharan black-African patients
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 ( r 2 > 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.
Stable warfarin dose prediction in sub‐Saharan African patients: A machine‐learning approach and external validation of a clinical dose–initiation algorithm
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.
Ethically acceptable consent approaches to adolescent research in South Africa
BackgroundAdolescents are a unique population with significant unmet health needs. They are often excluded from research that may benefit them as they are perceived as vulnerable and needing protection from research participation. For Research Ethics Committees, conflicting positions in statutes, regulations and ethical guidelines about who provides informed consent for adolescent involvement in health research can be a significant barrier to approving adolescent research. For researchers, the requirement for parental/guardian proxy consent or prolonged approval processes may potentially result in the exclusion of those adolescents most vulnerable and at risk, particularly if issues such as gender-based violence, gender identity, sexuality and sexual practices are in question.ObjectivesTo describe the challenges to adolescent research and suggest strategies to address these.MethodWe consider the legal and ethical framework in South Africa regarding the consenting age for adolescents in research, outline the challenges and, using examples of best practices, suggest strategies to address the current conundrum.ResultsWe suggest three principles to guide Research Ethics Committees on their approach to reviewing health research involving adolescents. Strategies to develop ethically acceptable approaches to adolescent research and consent processes are described, which include community involvement. We elaborate on examples of nuanced approaches to adolescent research.ConclusionThe inclusion of adolescents in research is critical in informing appropriate and effective health services for this vulnerable population, whilst providing an opportunity to link them into care and services where relevant.
A “Bundle of Care” to Improve Anticoagulation Control in Patients Receiving Warfarin in Uganda and South Africa: Protocol for an Implementation Study
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. 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. 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. 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. 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. DERR1-10.2196/46710.