How Patients Take Malaria Treatment: A Systematic Review of the Literature on Adherence to Antimalarial Drugs

Universitat Rovira i Virgili, Spain
PLoS ONE (Impact Factor: 3.23). 01/2014; 9(1):e84555. DOI: 10.1371/journal.pone.0084555
Source: PubMed


High levels of patient adherence to antimalarial treatment are important in ensuring drug effectiveness. To achieve this goal, it is important to understand levels of patient adherence, and the range of study designs and methodological challenges involved in measuring adherence and interpreting results. Since antimalarial adherence was reviewed in 2004, there has been a major expansion in the use of artemisinin-based combination therapies (ACTs) in the public sector, as well as initiatives to make them more widely accessible through community health workers and private retailers. These changes and the large number of recent adherence studies raise the need for an updated review on this topic.
We conducted a systematic review of studies reporting quantitative results on patient adherence to antimalarials obtained for treatment.
The 55 studies identified reported extensive variation in patient adherence to antimalarials, with many studies reporting very high adherence (90-100%) and others finding adherence of less than 50%. We identified five overarching approaches to assessing adherence based on the definition of adherence and the methods used to measure it. Overall, there was no clear pattern in adherence results by approach. However, adherence tended to be higher among studies where informed consent was collected at the time of obtaining the drug, where patient consultations were directly observed by research staff, and where a diagnostic test was obtained.
Variations in reported adherence may reflect factors related to patient characteristics and the nature of their consultation with the provider, as well as methodological variations such as interaction between the research team and patients before and during the treatment. Future studies can benefit from an awareness of the impact of study procedures on adherence outcomes, and the identification of improved measurement methods less dependent on self-report.

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Available from: Catherine Goodman, Feb 11, 2014
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    • "Patient adherence is a major determinant of the therapeutic response to antimalarial medications (Yeung & White 2005). Poor adherence, the inability of patients to take their medications at the right dose, correct dosing frequency and recommended treatment frequency (Van den Bemt et al. 2012; Bruxvoort et al. 2014) is a common practice in endemic regions (Depoortere et al. 2004; Fogg et al. 2004). Factors related to poor patient acceptance and adherence not only result to treatment failure, but may lead to higher treatment costs and even resistance (Yeung and White, 2005; Banek et al. 2014). "

    Full-text · Article · Dec 2015
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    • "Studies conducted across the world have reported varying levels of adherence to ACT both in the public and retail sectors. Moreover, two recently published reviews also noted this wide variation in adherence to ACT [10] [11]. This meta-analysis was therefore conducted to derive pooled estimates of prevalence and predictors of adherence to ACTs since adherence has been shown to be a key challenge in the implementation and adoption of ACT [12] "
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    ABSTRACT: Adherence to artemisinin-based combination therapy (ACT) is not clearly defined. This meta-analysis determines the prevalence and predictors of adherence to ACT. Twenty-five studies and six substudies met the inclusion criteria. The prevalence of ACT adherence in the public sector was significantly higher compared to retail sector (76% and 45%, resp., ). However, ACT adherence was similar across different ACT dosing regimens and formulations. In metaregression analysis prevalence estimates of adherence significantly decrease with increasing year of study publication . Factors found to be significant predictors of ACT adherence were years of education ≥ 7 odds ratio (OR) (95% CI) = 1.63 (1.05-2.53), higher income 2.0 (1.35-2.98), fatty food 4.6 (2.49-8.50), exact number of pills dispensed 4.09 (1.60-10.7), and belief in traditional medication for malaria 0.09 (0.01-0.78). The accuracy of pooled estimates could be limited by publication bias, and differing methods and thresholds of assessing adherence. To improve ACT adherence, educational programs to increase awareness and understanding of ACT dosing regimen are interventions urgently needed. Patients and caregivers should be provided with an adequate explanation at the time of prescribing and/or dispensing ACT.
    Full-text · Article · Jul 2015 · Journal of Tropical Medicine
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    • "In practice, full adherence to anti-malarial drug regimens can be less than 50% in ‘real life’ situations [47]. Reasons for non-adherence to anti-malarials are manifold, including adverse events (AEs) [48], rapid clinical recovery [42,48-52], misunderstanding of instructions [50,52] and, especially in children, difficulties in administration [48,50-52] and fear from over-dosing (‘too many tablets’) [50,52]. "
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    ABSTRACT: Successful programmatic use of anti-malarials faces challenges that are not covered by standard drug development processes. The development of appropriate pragmatic dosing regimens for low-resource settings or community-based use is not formally regulated, even though these may alter factors which can substantially affect individual patient and population level outcome, such as drug exposure, patient adherence and the spread of drug resistance and can affect a drug's reputation and its eventual therapeutic lifespan. An in silico pharmacological model of anti-malarial drug treatment with the pharmacokinetic/pharmacodynamic profiles of artemether-lumefantrine (AM-LF, Coartem(R)) and dihydroartemisinin-piperaquine (DHA-PPQ, Eurartesim(R)) was constructed to assess the potential impact of programmatic factors, including regionally optimized, age-based dosing regimens, poor patient adherence, food effects and drug resistance on treatment outcome at population level, and compared both drugs' susceptibility to these factors. Compared with DHA-PPQ, therapeutic effectiveness of AM-LF seems more robust to factors affecting drug exposure, such as age- instead of weight-based dosing or poor adherence. The model highlights the sub-optimally low ratio of DHA:PPQ which, in combination with the narrow therapeutic dose range of PPQ compared to DHA that drives the weight or age cut-offs, leaves DHA at a high risk of under-dosing. Pharmacological modelling of real-life scenarios can provide valuable supportive data and highlight modifiable determinants of therapeutic effectiveness that can help optimize the deployment of anti-malarials in control programmes.
    Full-text · Article · Apr 2014 · Malaria Journal
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