Economic evaluation of an alternative drug to sulfadoxine-pyrimethamine as intermittent preventive treatment of malaria in pregnancy

Household costs associated with seeking malaria treatment during pregnancy: evidence from Burkina Faso and The Gambia

Background

Malaria in pregnancy remains a major health threat in sub-Saharan Africa to both expectant mothers and their unborn children. To date, there have been very few studies focused on the out of pocket costs associated with seeking treatment for malaria during pregnancy.

Methods

A cross-sectional survey was undertaken in Burkina Faso and The Gambia to estimate the direct and indirect costs associated with outpatient consultations (OP) and inpatient admissions (IP). Direct costs were broken down into medical (admission fees, drug charges, and laboratory fees), and non-medical (transportation and food). Indirect costs reflected time lost due to illness. In total, 220 pregnant women in Burkina Faso and 263 in The Gambia were interviewed about their treatment seeking decisions, expenditure, time use and financial support associated with each malaria episode.

Results

In Burkina Faso 6.7% sought treatment elsewhere before their OP visits, and 27.1% before their IP visits. This compares to 1.3% for OP and 25.92% for IP in The Gambia. Once at the facility, the average direct costs (out of pocket) were 3.91US$ for an OP visit and 15.38US$ of an IP visit in Burkina Faso, and 0.80US$ for an OP visit and 9.19US$ for an IP visit in The Gambia. Inpatient direct costs were driven by drug costs (9.27US$) and transportation costs (2.72US$) in Burkina Faso and drug costs (3.44 US$) and food costs (3.44 US$) in The Gambia. Indirect costs of IP visits, valued as the opportunity cost of time lost due to the illness, were estimated at 11.85US$ in Burkina Faso and 4.07US$ in The Gambia. The difference across the two countries was mainly due to the longer time of hospitalization in Burkina Faso compared to The Gambia. In The Gambia, the vast majority of pregnant women reported receiving financial support from family members living abroad, most commonly siblings (65%).

Conclusions

High malaria treatment costs are incurred by pregnant women in Burkina Faso and The Gambia. Beyond the medical costs of fees and drugs, costs in terms of transport, food and time are significant drivers. The role of remittances, particularly their effect on accessing health care, needs further investigation.

Drugs for Intermittent Preventive Treatment of Malaria in Pregnancy: Current Knowledge and Way Forward

Malaria infection during pregnancy is an important driver of maternal and neonatal health in endemic countries. Intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) is recommended for malaria prevention at each scheduled antenatal care visit, starting at the second trimester, in areas of high and moderate transmission. However, the increased resistance to SP in some endemic areas challenges its effectiveness. Furthermore, SP is contraindicated in the first trimester of pregnancy and in HIV-infected women on co-trimoxazole prophylaxis due to potential drug–drug interactions. Thus, in recent last decades, several studies evaluated alternative drugs that could be used for IPTp. A comprehensive literature review was conducted to summarize the evidence on the efficacy and safety of antimalarial drugs being evaluated for IPTp. Chloroquine, amodiaquine, mefloquine and azithromycin as IPTp have proven to be worse tolerated than SP. Mefloquine was found to increase the risk of mother-to-child transmission of HIV. Dihydroartemisin-piperaquine currently constitutes the most promising IPTp drug alternative; it reduced the prevalence of malaria infection, and placental and clinical malaria in studies among HIV-uninfected women, and it is currently being tested in HIV-infected women. Research on effective antimalarial drugs that can be safely administered for prevention to pregnant women should be prioritized. Malaria prevention in the first trimester of gestation and tailored interventions for HIV-infected women remain key research gaps to be addressed.

Analysis of sulphadoxine-pyrimethamine resistance-associated mutations in Plasmodium falciparum isolates obtained from asymptomatic pregnant women in Ogun State, Southwest Nigeria

Intermittent preventive treatment in pregnancy with sulphadoxine-pyrimethamine (IPTp-SP) is one of the main strategies for protecting pregnant women, fetus, and their new-born against adverse effects of P. falciparum infection. The development of the drug resistance linked to mutations in P. falciparum dihydrofolate reductase gene (pfdhfr) and P. falciparum dihydropteroate synthase gene (pfdhps), is currently threatening the IPTp-SP approach. This study determined the prevalence of pfdhfr and pfdhps mutations in isolates obtained from pregnant women with asymptomatic P. falciparum infection in Nigerian. Additionally, P. falciparum genetic diversity and multiplicity of infection (MOI) was assessed by genotyping the P. falciparum merozoite surface Protein 1 and 2 (pfmsp-1 and pfmsp-2) genes. The pfdhfr and pfdhps were genotyped by direct sequencing, and the pfmsp-1 and pfmsp-2 fragment analysis by polymerase chain reaction was used to determine P. falciparum genetic diversity. Of the 406 pregnant women recruited, 123 had P. falciparum infection by PCR, and of these, 52 were successfully genotyped for pfdhfr and 42 for pfdhps genes. The pfdhfr triple-mutant parasites (N51I, C59R, and S108N) or the IRN haplotype were predominant (98%), whereas pfdhfr mutations C50R and I164L did not occur. For pfdhps gene, the prevalence of A437G, A581G, A436A, and A613S mutations were 98, 71, 55, and 36%, respectively. Nineteen (44%) isolates with quintuple mutations (CIRNI- SGKGA) had the highest combined pfdhfr-pfdhps haplotype. Isolates with sextuple mutants; CIRNI- AGKAS and CIRNI- AGKGA had a prevalence of 29 and 14%, respectively. High genetic diversity (7 pfmsp-1 alleles and 10 pfmsp-2 alleles) and monoclonal infection rate (76%) was observed. This study demonstrated a continuous high prevalence of pfdhfr mutation and an increase in pfdhps mutations associated with SP-resistance in southwest Nigeria. Continuous surveillance of IPTp-SP effectiveness and consideration of alternative IPTp strategies is recommended.

Systematic review of microeconomic analysis of pregnancy-associated malaria

Introduction

Pregnancy-associated malaria (PAM) is a health problem with serious clinical, epidemiological and economic effects.

Purpose

To analyze the microeconomic evaluations of PAM reported in the world scientific literature.

Methods

Systematic review with 15 different search strategies in PubMed, ScienceDirect, Scielo, Google Scholar and Malaria in Pregnancy (MiP) Library. A search, selection and extraction protocol was applied, which guaranteed completeness and reproducibility in accordance with preferred reporting items for systematic reviews and meta-analysis guidelines. The methodological quality was evaluated using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) guide. The analysis were based on frequencies, costs and average and incremental cost-effectiveness ratios in 2018 US dollars adjusted for purchasing power parity.

Results

Twenty-two evaluations published between 1990 and 2018 were analyzed, of which 82% addressed cost-effectiveness in Africa. Twelve interventions were studied; of these, intermittent preventive treatment in pregnant women with sulfadoxine-pyrimethamine (IPTp-SP) was the most frequent strategy. The main outcomes were low birth weight, anaemia and DALYs avoided. The best average cost-effectiveness ratio was reported in IPTp-SP with a cost of US$ 2 per DALY avoided, followed by the administration of IPTp-SP in pregnant women with HIV (US$ 14.2).

Conclusions

The studies focus on Africa with a high heterogeneity in the interventions, outcomes, resources and populations studied. All the interventions were highly cost-effective, which demonstrates the importance of including prevention, care and control resources for PAM as a priority in health sector budgets. This is especially true considering the importance of its intervention for social progress and overcoming poverty in endemic areas.

Systemic inflammation is associated with malaria and preterm birth in women living with HIV on antiretrovirals and co-trimoxazole

Women living with HIV (WLHIV) have an increased risk of malaria in pregnancy (MiP). It is unclear if MiP in WLHIV causes a systemic inflammatory response and increases the risk of adverse birth outcomes, especially for women receiving antiretroviral therapy (ART) and daily trimethoprim-sulfamethoxazole (TMP/SXT). We analyzed repeated plasma samples in a cohort of malaria-exposed Ugandan WLHIV receiving ART and daily TMP/SXT to examine changes in inflammatory markers across pregnancy and their association with birth outcomes. Concentrations of CHI3L1, CRP, IL-18BP, IL-6, sICAM-1, and sTNFR2 were quantified by ELISA in 1115 plasma samples collected over pregnancy from 326 women. MiP was associated with increased sTNFR2, sICAM-1 and IL-18BP concentrations across pregnancy. Women who delivered preterm had elevated concentrations of sTNFR2 and altered levels of IL-6 during pregnancy. Women with sTNFR2 concentrations in the highest quartile within 6 weeks of delivery had an increased relative risk of preterm birth. Our results indicate that despite daily TMP/SXT, MiP in WLHIV induced a systemic inflammatory response that was associated with an increased risk of preterm birth. These findings highlight the need for additional strategies to protect WLHIV from malaria infection in pregnancy to promote healthy outcomes for mother and child.

The prevalence and antifolate drug resistance profiles of Plasmodium falciparum in study participants randomized to discontinue or continue cotrimoxazole prophylaxis

Objective

Cotrimoxazole prevents opportunistic infections including falciparum malaria in HIV-infected individuals but there are concerns of cross-resistance to other antifolate drugs such as sulphadoxine-pyrimethamine (SP). In this study, we investigated the prevalence of antifolate-resistance mutations in Plasmodium falciparum that are associated with SP resistance in HIV-infected individuals on antiretroviral treatment randomized to discontinue (STOP-CTX), or continue (CTX) cotrimoxazole in Western Kenya.

Design

Samples were obtained from an unblinded, non-inferiority randomized controlled trial where participants were recruited on a rolling basis for the first six months of the study, then followed-up for 12 months with samples collected at enrollment, quarterly, and during sick visits.

Method

Plasmodium DNA was extracted from blood specimens. Initial screening to determine the presence of Plasmodium spp. was performed by quantitative reverse transcriptase real-time PCR, followed by genotyping for the presence of SP-resistance associated mutations by Sanger sequencing.

Results

The prevalence of mutant haplotypes associated with SP-resistant parasites in pfdhfr (51I/59R/108N) and pfdhps (437G/540E) genes were significantly higher (P = 0.0006 and P = 0.027, respectively) in STOP-CTX compared to CTX arm. The prevalence of quintuple haplotype (51I/59R/108N/437G/540E) was 51.8% in STOP-CTX vs. 6.3% (P = 0.0007) in CTX arm. There was a steady increase in mutant haplotypes in both genes in STOP-CTX arm overtime through the study period, reaching statistical significance (P < 0.0001).

Conclusion

The frequencies of mutations in pfdhfr and pfdhps genes were higher in STOP-CTX arm compared to CTX arm, suggesting cotrimoxazole effectively controls and selects against SP-resistant parasites.

Trial registration

ClinicalTrials.gov NCT01425073

Cotrimoxazole, an antifolate, is a fixed-dose trimethoprim-sulfamethoxazole used to prevent opportunistic infections including malaria in HIV-infected individuals. There are concerns that widespread use of cotrimoxazole for prophylaxis may result in selection of P. falciparum parasites with cross-resistance to other antifolate drugs such as sulphadoxine-pyrimethamine (SP), which is used as intermittent preventive treatment of malaria in pregnancy (IPTp) and in infants (IPTi) in Africa. This sub-study used samples from a clinical trial in which HIV-infected individuals on antiretroviral treatment were randomized to discontinue (STOP-CTX) or continue (CTX) cotrimoxazole prophylaxis for 12 months. The sub-study was designed to assess whether taking cotrimoxazole increased the risk of selecting for parasites with SP-resistant mutations in HIV-infected individuals. Samples were genotyped by sequencing to assess the prevalence of mutations associated with SP-resistance. We found there was no risk of selecting for parasites with SP-resistance mutations while on cotrimoxazole. In fact, the opposite was true; cotrimoxazole controlled parasites carrying SP-resistance mutations as evident by the gradual increase in the prevalence of parasites with mutant alleles in the STOP-CTX arm and not in the CTX-arm. We concluded that cotrimoxazole remains effective in controlling malaria infection despite of the high prevalence of SP-resistant parasites, and its use does not select for SP mutations.

Prevention of malaria in pregnancy

Malaria remains one of the most preventable causes of adverse birth outcomes. Intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine is used to prevent malaria, but resistance to this drug combination has decreased its efficacy and new alternatives are needed. In Africa, a meta-analysis showed three-course or monthly IPTp with sulfadoxine-pyrimethamine to be safe and more effective than the original two-course sulfadoxine-pyrimethamine strategy, prompting WHO to update its policy in 2012. Although resistance to sulfadoxine-pyrimethamine reduces the parasitological efficacy of IPTp, this drug combination remains associated with reduced incidence of low birthweight in areas where prevalence of parasites with quintuple Plasmodium falciparum dihydrofolate reductase (Pfdhfr) and dihydropteroate synthetase (Pfdhps) mutations is greater than 90%. Nevertheless, its effectiveness is compromised in women infected with sextuple mutant parasites. Six trials of IPTp showed that neither amodiaquine, mefloquine, nor chloroquine-azithromycin are suitable replacements for sulfadoxine-pyrimethamine because of poor tolerability. Furthermore, four trials showed that intermittent screening and treatment with the current generation of malaria rapid diagnostic tests was not a suitable alternative strategy to IPTp with sulfadoxine-pyrimethamine, even in areas with high prevalence of quintuple mutations. Two trials showed that IPTp with dihydroartemisinin-piperaquine was well tolerated, effective, and acceptable for IPTp, with monthly regimens being the most effective. Coverage of IPTp and insecticide-treated nets continues to lag behind targets. The key barriers to uptake are well documented, and many are open to intervention. Outside of Africa, a single trial suggests a potential role for integrated approaches that combine sulfadoxine-pyrimethamine with azithromycin for IPTp in areas of Papua New Guinea where malaria transmission is high. Modelling analysis suggests the importance of the prevention of malaria early in pregnancy and the need to protect pregnant women declines more slowly than the rate at which transmission declines. Improved funding has led to an increase in the number of prevention trials in the past decade, showing the value of more sustained protection with monthly IPTp regimens. There is a need for confirmatory trials of the safety, efficacy, and feasibility of IPTp with dihydroartemisinin-piperaquine, for studies of intermittent screening and treatment with more sensitive rapid diagnostic tests, for studies of integrated strategies for malaria and other co-infections, and for studies of prevention strategies for malaria in pregnant women who are HIV-positive and living outside of Africa. Additional research is required on how to improve uptake of WHO's updated policy on IPTp with sulfadoxine-pyrimethamine and insecticide-treated nets.

Burden, pathology, and costs of malaria in pregnancy: new developments for an old problem

Over the past 10 years, knowledge of the burden, economic costs, and consequences of malaria in pregnancy has improved, and the prevalence of malaria caused by Plasmodium falciparum has declined substantially in some geographical areas. In particular, studies outside of Africa have increased the evidence base of Plasmodium vivax in pregnancy. Rapid diagnostic tests have been poor at detecting malaria in pregnant women, while PCR has shown a high prevalence of low density infection, the clinical importance of which is unknown. Erythrocytes infected with P falciparum that express the surface protein VAR2CSA accumulate in the placenta, and VAR2CSA is an important target of protective immunity. Clinical trials for a VAR2CSA vaccine are ongoing, but sequence variation needs to be carefully studied. Health system and household costs still limit access to prevention and treatment services. Within the context of malaria elimination, pregnant women could be used to monitor malaria transmission. This Series paper summarises recent progress and highlights unresolved issues related to the burden of malaria in pregnancy.

Cost-effectiveness analysis of malaria interventions using disability adjusted life years: a systematic review

BACKGROUND

Malaria continues to be a public health problem despite past and on-going control efforts. For sustenance of control efforts to achieve the malaria elimination goal, it is important that the most cost-effective interventions are employed. This paper reviews studies on cost-effectiveness of malaria interventions using disability-adjusted life years.

METHODS

A review of literature was conducted through a literature search of international peer-reviewed journals as well as grey literature. Searches were conducted through Medline (PubMed), EMBASE and Google Scholar search engines. The searches included articles published in English for the period from 1996 to 2016. The inclusion criteria for the study were type of malaria intervention, year of publication and cost-effectiveness ratio in terms of cost per DALY averted. We included 40 studies which specifically used the DALY metric in cost-effectiveness analysis (CEA) of malaria interventions.

RESULTS

The majority of the reviewed studies (75%) were done using data from African settings with the majority of the interventions (60.0%) targeting all age categories. Interventions included case treatment, prophylaxis, vector control, insecticide treated nets, early detection, environmental management, diagnosis and educational programmes. Sulfadoxine-pyrimethamine was the most common drug of choice in malaria prophylaxis, while artemisinin-based combination therapies were the most common drugs for case treatment. Based on guidelines for CEA, most interventions proved cost-effective in terms of cost per DALYs averted for each intervention.

CONCLUSION

The DALY metric is a useful tool for determining the cost-effectiveness of malaria interventions. This paper demonstrates the importance of CEA in informing decisions made by policy makers.

The influence of pregnancy on the pharmacokinetic properties of artemisinin combination therapy (ACT): a systematic review

Background

Pregnancy has been reported to alter the pharmacokinetic properties of anti-malarial drugs, including the different components of artemisinin-based combination therapy (ACT). However, small sample sizes make it difficult to draw strong conclusions based on individual pharmacokinetic studies. The aim of this review is to summarize the evidence of the influence of pregnancy on the pharmacokinetic properties of different artemisinin-based combinations.

Methods

A PROSPERO-registered systematic review to identify clinical trials that investigated the influence of pregnancy on the pharmacokinetic properties of different forms of ACT was conducted, following PRISMA guidelines. Without language restrictions, Medline/PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, LILACS, Biosis Previews and the African Index Medicus were searched for studies published up to November 2015. The following components of ACT that are currently recommend by the World Health Organization as first-line treatment of malaria in pregnancy were reviewed: artemisinin, artesunate, dihydroartemisinin, lumefantrine, amodiaquine, mefloquine, sulfadoxine, pyrimethamine, piperaquine, atovaquone and proguanil.

Results

The literature search identified 121 reports, 27 original studies were included. 829 pregnant women were included in the analysis. Comparison of the available studies showed lower maximum concentrations (C_max) and exposure (AUC) of dihydroartemisinin, the active metabolite of all artemisinin derivatives, after oral administration of artemether, artesunate and dihydroartemisinin in pregnant women. Low day 7 concentrations were commonly seen in lumefantrine studies, indicating a low exposure and possibly reduced efficacy. The influence of pregnancy on amodiaquine and piperaquine seemed not to be clinically relevant. Sulfadoxine plasma concentration was significantly reduced and clearance rates were higher in pregnancy, while pyrimethamine and mefloquine need more research as no general conclusion can be drawn based on the available evidence. For atovaquone, the available data showed a lower maximum concentration and exposure. Finally, the maximum concentration of cycloguanil, the active metabolite of proguanil, was significantly lower, possibly compromising the efficacy.

Conclusion

These findings suggest that reassessment of the dose of the artemisinin derivate and some components of ACT are necessary to ensure the highest possible efficacy of malaria treatment in pregnant women. However, for most components of ACT, data were insufficient and extensive research with larger sample sizes will be necessary to identify the exact influences of pregnancy on the pharmacokinetic properties of different artemisinin-based combinations. In addition, different clinical studies used diverse study designs with various reported relevant outcomes. Future pharmacokinetic studies could benefit from more uniform designs, in order to increase quality, robustness and effectiveness.

Study registration: CRD42015023756 (PROSPERO)

Electronic supplementary material

The online version of this article (doi:10.1186/s12936-016-1160-6) contains supplementary material, which is available to authorized users.

Global Call to Action to scale-up coverage of intermittent preventive treatment of malaria in pregnancy: seminar report

In 2014, a global ‘Call to Action’ seminar for the scale-up of intermittent preventive treatment of malaria in pregnancy was held during the 63rd Annual Meeting of the American Society of Tropical Medicine and Hygiene. This report summarizes the presentations and main discussion points from the meeting.