OVERCOMING THE CHALLENGES
Overcoming the multitude of challenges faced by anticoagulation services and patients requiring anticoagulation in SSA require a multifaceted approach. “Warfarin care bundles” are effective and viable strategies, as shown in a recent network meta-analysis of anticoagulation interventions.[127] In SSA such a warfarin care bundle must include both process-centred and patient-centred activities, the exact combination of which will be specific to each setting and will depend on cost-effectiveness to guide rational allocation of limited resources. In making process changes, it will be important to leverage off existing successful systems, such as HIV treatment programmes,[128] and to ensure these changes are embedded in a quality-improvement framework, with regular feedback to patients, clinicians, and managers.
First, we would propose patient-centred anticoagulation education and adherence support. These interventions have shown benefit on patients’ knowledge, adherence, and INR control in a few individual SSA studies[13,14,116] and may be of particular benefit in vulnerable populations.[129] As pharmacists and doctors are a scarce resource in Africa, these education and support tasks can be successfully shifted to mid-level health care workers.[7] SSA has extensive expertise on providing adherence support to patients with HIV, and education and adherence support for patients with non-communicable diseases should build on these already-existing systems.[130]
Process-centred activities may include decentralisation of anticoagulation services, setting up of anticoagulation clinics, improving access to warfarin (including formulations other than the 5 mg tablet), 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. Decentralised anticoagulation clinics can be successfully implemented in SSA, with improved outcomes (and better cost-effectiveness) compared to those achieved at a central referral hospital.[93] Point-of-care INR testing has also been successfully implemented in SSA, drastically decreasing the number of visits patients have to make to the clinic.[87] However, the high cost of test strips is problematic, and relying on donations and subsidies is not sustainable. Localised dose initiation and dose adjustment algorithms must consider the comorbidities and potential drug interactions that are prevalent in SSA, such as HIV, tuberculosis, antiretrovirals, antituberculosis therapy, co-trimoxazole, and herbal / traditional medicines. These algorithms must be easy to implement, for example being paper-based, and should recommend small, percentage-based dose adjustments.[102]
One example of an effective anticoagulation programme combining multiple interventions came from Rwanda.[131] In this programme, specialist non-communicable disease nurses deliver post-operative care to VHD patients in decentralised clinics. Standard dosing algorithms are used, while nurses are supervised and supported by cardiologists, using mobile communications. Adherence support, as well as financial support, is offered to patients. While this small study did not report the effect of this programme on TTR, low mortality was described, and there were no bleeding or thrombotic complications.[131]
DOACs may be a solution to some anticoagulation challenges in SSA: while they are still prohibitively expensive to most African patients and health care systems, they will in the future come off patent, and generics may be more affordable. DOACs have the benefit of being used at fixed rather than individualised doses and do not require routine monitoring.[73] However, DOACs come with their own set of challenges. They are contra-indicated in valvular heart disease, a significant group of patients in SSA, and require dose adjustment / are contra-indicated in severe renal impairment. DOACs have shorter half-lives than warfarin, making strict adherence more critical; ironically, without regular monitoring, adherence problems may be missed in patients on DOACs.[73] DOACs are also subject to drug-drug interactions: notably for SSA, these include interactions with rifampicin and many antiretroviral agents.[132] Finally, the management of major bleeding occurring with DOACs will require specific protocols, localised for SSA.[73]