Risk factors for mortality from imported falciparum malaria in the United Kingdom over 20 years: an observational study.

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 (R(2) = 0.72, P