Risk factors for mortality from imported falciparum malaria in the United Kingdom over 20 years: an observational studyBMJ 2012; 344 doi: https://doi.org/10.1136/bmj.e2116 (Published 27 March 2012) Cite this as: BMJ 2012;344:e2116
- Anna M Checkley, lecturer1,
- Adrian Smith, senior clinical research scientist2,
- Valerie Smith, data manager1,
- Marie Blaze, data manager1,
- David Bradley, emeritus professor of tropical epidemiology1,
- Peter L Chiodini, honorary professor and director MRL; consultant parasitologist13,
- Christopher J M Whitty, professor of international health1
- 1HPA Malaria Reference Laboratory and London School of Hygiene & Tropical Medicine, London WC1B 3DP, UK
- 2University of Oxford
- 3Hospital for Tropical Diseases London
- Correspondence to: C J M Whitty
- Accepted 31 January 2012
Objectives To determine which travellers with malaria are at greatest risk of dying, highlighting factors which can be used to target health messages to travellers.
Design Observational study based on 20 years of UK national data.
Setting National register of malaria cases.
Participants 25 054 patients notified with Plasmodium falciparum malaria, of whom 184 died, between 1987 and 2006.
Main outcome measures Comparison between those with falciparum malaria who died and non-fatal cases, including age, reason for travel, country of birth, time of year diagnosed, malaria prophylaxis used.
Results Mortality increased steadily with age, with a case fatality of 25/548 (4.6%) in people aged >65 years, adjusted odds ratio 10.68 (95% confidence interval 6.4 to 17.8), P<0.001 compared with 18–35 year olds. There were no deaths in the ≤5 year age group. Case fatality was 3.0% (81/2740 cases) in tourists compared with 0.32% (26/8077) in travellers visiting friends and relatives (adjusted odds ratio 8.2 (5.1 to 13.3), P<0.001). Those born in African countries with endemic malaria had a case fatality of 0.4% (36/8937) compared with 2.4% (142/5849) in others (adjusted odds ratio 4.6 (3.1 to 9.9), P<0.001). Case fatality was particularly high from the Gambia. There was an inverse correlation in mortality between region of presentation and number of cases seen in the region (R2=0.72, P<0.001). Most delay in fatal cases was in seeking care.
Conclusions Most travellers acquiring malaria are of African heritage visiting friends and relatives. In contrast the risks of dying from malaria once acquired are highest in the elderly, tourists, and those presenting in areas in which malaria is seldom seen. Doctors often do not think of these as high risk groups for malaria; for this reason they are important groups to target in pre-travel advice.
Contributors: The study was devised by AC, PLC, DB, CW. Data collection was by MB and VS. Data validation on deaths was by AC, and on cases by AS. Data analysis was by AC, AS and CW. All authors contributed to writing the paper. AC is the guarantor.
Funding: The Malaria Reference Laboratory is funded by the UK Health Protection Agency. AC has an Academic Clinical Lectureship. PLC is supported by the UCL Hospitals Comprehensive Biomedical Research Centre Infection Theme.
Competing interests: All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: PLC had support from the Malaria Reference Laboratory for the submitted work; PLC has received an honorarium from GlaxoSmithKline for a lecture on malaria in the previous 3 years. No other financial relationships with any organisations that might have an interest in the submitted work in the previous 3 years; no other relationships or activities that could appear to have influenced the submitted work.
Data sharing: Data on cases imported by year available from the corresponding author.
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