Adherence to Artemisinin Combination Therapy for Malaria
Artemisinin Combination Therapy (ACT) is the WHO recommended first-line therapy for Plasmodium falciparum malaria in nearly all malaria endemic countries and is the most effective treatment for the disease. Several recent papers have stressed the urgency of developing strategies to stem parasite resistance to artemisinin, as resistant strains have already been detected. The development of widespread resistance to previous generations of inexpensive, commonly purchased anti-malarials contributed to increases in malaria mortality among African children against a backdrop of overall declines in child mortality in this region.
Volumes of ACT purchased and distributed through private and retail sector channels are increasing substantially, though availability in retail outlets is still far from universal. Since the majority of malaria treatment-seeking occurs in these sectors, and ACT is 5 to 24 times more expensive than alternative anti-malarials, price has been a major barrier to transitioning anti-malarial purchases from older, less effective medicines to ACT. The Affordable Medicines Facility - malaria (AMFm) is a pilot initiative in seven African countries that aims to substantially reduce the price of ACT through subsidies. Through this ACT price reduction, the AMFm also aims to encourage the purchase of ACT over artemisinin monotherapies (AMT), as AMT use can be a serious risk for parasite resistance to artemisinin-based drugs. However, the AMFm's ultimate impact in protecting artemisinin will be inhibited if ACT is being used inappropriately.
Non-adherence to recommended treatment regimens, resulting in sub-therapeutic drug concentrations is a key driver of parasite resistance. Non-completion of a full standard regimen also exposes patients to recurrent malaria infections and can increase related morbidity and mortality. Previous studies have estimated a range of adherence rates to ACT obtained in the public sector, some finding nearly perfect adherence and others finding adherence rates as low as 39%, but with estimates varying importantly with the strictness of the definition, research methods and context. It is questionable to what extent results from these studies can be generalized to patients purchasing ACT from private sector outlets such as licensed pharmacies, licensed and unlicensed drug shops, and other informal outlets like general stores and market stands. In most public sector studies, adherence is measured with home visits to patients who received ACT free-of-charge after a confirmed malaria diagnosis and often after receiving counseling, dosing instructions and side effects warnings from a trained provider who often supervised the first dose. To the extent that diagnosis, instructions and supervision can improve adherence, retail sector adherence rates are likely to be lower. Patient characteristics could differ importantly as well, e.g. if people are more likely to visit the public sector when the patient is young and the illness is severe. Finally, retail sector customers may only be able to afford a sub-therapeutic dose of ACT and may choose to keep pills for the next time a household member is ill to defray future expense. For all of these reasons, it may be inappropriate to forecast adherence rates to ACT provided through the retail sector based on existing public sector estimates.
As financing and other initiatives aiming to increase access to ACT reach the substantial share of malaria patients who seek treatment in the retail sector, it is increasingly crucial to have estimates of adherence rates among this population. Understanding ACT adherence in the retail sector is necessary for developing appropriate strategies to prevent the emergence of artemisinin resistance. This study estimates adherence rates and explores associated characteristics among patients purchasing over-the-counter ACT in Uganda. It is the first study to use follow-up methods to estimate adherence rates to subsidized, over-the-counter ACT.
Background
Artemisinin Combination Therapy (ACT) is the WHO recommended first-line therapy for Plasmodium falciparum malaria in nearly all malaria endemic countries and is the most effective treatment for the disease. Several recent papers have stressed the urgency of developing strategies to stem parasite resistance to artemisinin, as resistant strains have already been detected. The development of widespread resistance to previous generations of inexpensive, commonly purchased anti-malarials contributed to increases in malaria mortality among African children against a backdrop of overall declines in child mortality in this region.
Volumes of ACT purchased and distributed through private and retail sector channels are increasing substantially, though availability in retail outlets is still far from universal. Since the majority of malaria treatment-seeking occurs in these sectors, and ACT is 5 to 24 times more expensive than alternative anti-malarials, price has been a major barrier to transitioning anti-malarial purchases from older, less effective medicines to ACT. The Affordable Medicines Facility - malaria (AMFm) is a pilot initiative in seven African countries that aims to substantially reduce the price of ACT through subsidies. Through this ACT price reduction, the AMFm also aims to encourage the purchase of ACT over artemisinin monotherapies (AMT), as AMT use can be a serious risk for parasite resistance to artemisinin-based drugs. However, the AMFm's ultimate impact in protecting artemisinin will be inhibited if ACT is being used inappropriately.
Non-adherence to recommended treatment regimens, resulting in sub-therapeutic drug concentrations is a key driver of parasite resistance. Non-completion of a full standard regimen also exposes patients to recurrent malaria infections and can increase related morbidity and mortality. Previous studies have estimated a range of adherence rates to ACT obtained in the public sector, some finding nearly perfect adherence and others finding adherence rates as low as 39%, but with estimates varying importantly with the strictness of the definition, research methods and context. It is questionable to what extent results from these studies can be generalized to patients purchasing ACT from private sector outlets such as licensed pharmacies, licensed and unlicensed drug shops, and other informal outlets like general stores and market stands. In most public sector studies, adherence is measured with home visits to patients who received ACT free-of-charge after a confirmed malaria diagnosis and often after receiving counseling, dosing instructions and side effects warnings from a trained provider who often supervised the first dose. To the extent that diagnosis, instructions and supervision can improve adherence, retail sector adherence rates are likely to be lower. Patient characteristics could differ importantly as well, e.g. if people are more likely to visit the public sector when the patient is young and the illness is severe. Finally, retail sector customers may only be able to afford a sub-therapeutic dose of ACT and may choose to keep pills for the next time a household member is ill to defray future expense. For all of these reasons, it may be inappropriate to forecast adherence rates to ACT provided through the retail sector based on existing public sector estimates.
As financing and other initiatives aiming to increase access to ACT reach the substantial share of malaria patients who seek treatment in the retail sector, it is increasingly crucial to have estimates of adherence rates among this population. Understanding ACT adherence in the retail sector is necessary for developing appropriate strategies to prevent the emergence of artemisinin resistance. This study estimates adherence rates and explores associated characteristics among patients purchasing over-the-counter ACT in Uganda. It is the first study to use follow-up methods to estimate adherence rates to subsidized, over-the-counter ACT.
SHARE
