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]