To study the diagnosis and outcomes in people admitted to hospital with a diagnosis
of severe malaria in areas with differing intensities of malaria transmission.
Prospective observational study of children and adults over the course a year.
10 hospitals in north east Tanzania.
17,313 patients were admitted to hospital; of these 4474 (2851 children aged under
5 years) fulfilled criteria for severe disease.
Details of the treatment given and outcome. Altitudes of residence (a proxy for transmission
intensity) measured with a global positioning system.
Blood film microscopy showed that 2062 (46.1%) of people treated for malaria had Plasmodium
falciparum (slide positive). The proportion of slide positive cases fell with increasing
age and increasing altitude of residence. Among 1086 patients aged > or = 5 years
who lived above 600 metres, only 338 (31.1%) were slide positive, while in children
< 5 years living in areas of intense transmission (< 600 metres) most (958/1392, 68.8%)
were slide positive. Among 2375 people who were slide negative, 1571 (66.1%) were
not treated with antibiotics and of those, 120 (7.6%) died. The case fatality in slide
negative patients was higher (292/2412, 12.1%) than for slide positive patients (142/2062,
6.9%) (P < 0.001). Respiratory distress and altered consciousness were the strongest
predictors of mortality in slide positive and slide negative patients and in adults
as well as children.
In Tanzania, malaria is commonly overdiagnosed in people presenting with severe febrile
illness, especially in those living in areas with low to moderate transmission and
in adults. This is associated with a failure to treat alternative causes of severe
infection. Diagnosis needs to be improved and syndromic treatment considered. Routine
hospital data may overestimate mortality from malaria by over twofold.