Cost effectiveness of intermittent screening followed by treatment versus intermittent preventive treatment during pregnancy in West Africa: analysis and modelling of results from a non-inferiority trial.
BACKGROUND
Emergence of high-grade sulfadoxine-pyrimethamine (SP) resistance in parts of Africa has led to growing concerns about the efficacy of intermittent preventive treatment of malaria during pregnancy (IPTp) with SP. The incremental cost-effectiveness of intermittent screening and treatment (ISTp) with artemether-lumefantrine (AL) as an alternative strategy to IPTp-SP was estimated followed by a simulation of the effects on cost-effectiveness of decreasing efficacy of IPTp-SP due to SP resistance. The analysis was based on results from a multi-centre, non-inferiority trial conducted in West Africa.


METHODS
A decision tree model was analysed from a health provider perspective. Model parameters for all trial countries with appropriate ranges and distributions were used in a probabilistic sensitivity analysis. Simulations were performed in hypothetical cohorts of 1000 pregnant women who received either ISTp-AL or IPTp-SP. In addition a cost-consequences analysis was conducted. Trial estimates were used to calculate disability-adjusted-life-years (DALYs) for low birth weight and severe/moderate anaemia (both shown to be non-inferior for ISTp-AL) and clinical malaria (inferior for ISTp-AL). Cost estimates were obtained from observational studies, health facility costings and public procurement databases. Results were calculated as incremental cost per DALY averted. Finally, the cost-effectiveness changes with decreasing SP efficacy were explored by simulation.


RESULTS
Relative to IPTp-SP, delivering ISTp-AL to 1000 pregnant women cost US$ 4966.25 more (95 % CI US$ 3703.53; 6376.83) and led to a small excess of 28.36 DALYs (95 % CI -75.78; 134.18), with LBW contributing 81.3 % of this difference. The incremental cost-effectiveness ratio was -175.12 (95 % CI -1166.29; 1267.71) US$/DALY averted. Simulations show that cost-effectiveness of ISTp-AL increases as the efficacy of IPTp-SP decreases, though the specific threshold at which ISTp-AL becomes cost-effective depends on assumptions about the contribution of bed nets to malaria control, bed net coverage and the willingness-to-pay threshold used.


CONCLUSIONS
At SP efficacy levels currently observed in the trial settings it would not be cost-effective to switch from IPTp-SP to ISTp-AL, mainly due to the substantially higher costs of ISTp-AL and limited difference in outcomes. The modelling results indicate thresholds below which IPT-SP efficacy must fall for ISTp-AL to become a cost-effective option for the prevention of malaria in pregnancy.
London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. silke.fernandes@lshtm.ac.uk.
Silke
http://orcid.org/0000-0001-7694-4233
S
Fernandes
ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
Elisa
E
Sicuri
Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Dentistry, Malaria Research and Training Centre, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali.
Diawara
D
Halimatou
Navrongo Health Research Centre, Navrongo, Ghana.
James
J
Akazili
Medical Research Council Unit, Fajara, Gambia.
Kalifa
K
Boiang
London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
Daniel
D
Chandramohan
Faculty of Health Sciences, University of Ouagadougou, Ouagadougou, Burkina Faso.
Sheikh
S
Coulibaly
Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Dentistry, Malaria Research and Training Centre, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali.
Sory Ibrahim
SI
Diawara
Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Dentistry, Malaria Research and Training Centre, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali.|Liverpool School of Tropical Medicine, Liverpool, UK.
Kassoum
K
Kayentao
Liverpool School of Tropical Medicine, Liverpool, UK.
Feiko
F
Ter Kuile
Institute of International Health, Immunology and Microbiology, Centre for Medical Parasitology and Institute of Veterinary Disease Biology, University of Copenhagen, Copenhagen, Denmark.
Pascal
P
Magnussen
School of Medicine, University of Health and Allied Sciences, Ho, Ghana.
Harry
H
Tagbor
Navrongo Health Research Centre, Navrongo, Ghana.
John
J
Williams
London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
Arouna
A
Woukeu
London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
Matthew
M
Cairns
London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
Brian
B
Greenwood
London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
Kara
K
Hanson
PLoS One. 2010 Oct 15;5(10):e13407
20976217
PLoS One. 2010 Dec 28;5(12):e14425
21203389
JAMA. 2006 Mar 8;295(10):1152-60
16522836
Emerg Infect Dis. 2013;19(9):null
23969132
Parasitology. 2011 Oct;138(12):1469-79
21835078
Trends Parasitol. 2010 Sep;26(9):447-56
20728060
JAMA. 2013 Feb 13;309(6):594-604
23403684
Am J Trop Med Hyg. 2001 Nov;65(5):614-22
11716124
Malar J. 2014 Jan 31;13:41
24484467
PLoS Med. 2014 Sep 23;11(9):e1001733
25247709
Lancet. 2012 Dec 15;380(9859):2129-43
23245605
Trop Med Int Health. 2006 May;11(5):569-77
16640608
Lancet Infect Dis. 2011 Mar;11(3):190-207
21273130
Cochrane Database Syst Rev. 2014 Oct 10;(10):CD000169
25300703
Trends Parasitol. 2013 Oct;29(10):505-15
24028889
PLoS Med. 2012;9(8):e1001292
22904691
PLoS One. 2009;4(2):e4569
19238219
Pharmacoeconomics. 1998 Mar;13(3):277-88
10178653
Lancet. 2012 Dec 15;380(9859):2071-94
23245603
PLoS One. 2015 Aug 10;10(8):e0132247
26258474
Lancet Infect Dis. 2007 Feb;7(2):93-104
17251080
N Engl J Med. 2016 Mar 10;374(10):928-39
26962728
Proc Natl Acad Sci U S A. 2009 Jun 2;106(22):9027-32
19451638
J Nutr. 2001 Feb;131(2S-2):604S-614S; discussion 614S-615S
11160593
JAMA. 2007 Jun 20;297(23):2603-16
17579229
Lancet. 2015 Dec 19;386(10012):2507-19
26429700
Lancet Infect Dis. 2013 Dec;13(12):1029-42
24054085