Falciparum malaria and HIV-1 in hospitalized adults in Maputo, Mozambique: does HIV-infection obscure the malaria diagnosis?

Background: The potential impact of HIV-1 on falciparum malaria has been difficult to determine because of diagnostic problems and insufficient epidemiological data. Methods: In a prospective, cross-sectional study, clinical and laboratory data was registered consecutively for all adults admitted to a medical ward in the Central Hospital of Maputo, Mozambique, during two months from 28(th) October 2006. Risk factors for fatal outcome were analysed. The impact of HIV on the accuracy of malaria diagnosis was assessed, comparing "Presumptive malaria", a diagnosis assigned by the ward clinicians based on fever and symptoms suggestive of malaria in the absence of signs of other infections, and "Verified malaria", a malaria diagnosis that was not rejected during retrospective review of all available data. Results: Among 333 included patients, fifteen percent (51/333) had "presumptive malaria", ten percent (28 of 285 tested persons) had positive malaria blood slides, while 69.1% (188/272) were HIV positive. Seven percent (n = 23) had "verified malaria", after the diagnosis was rejected in patients with neck stiffness or symptom duration longer than 2 weeks (n = 5) and persons with negative (n = 19) or unknown malaria blood slide (n = 4). Clinical stage of HIV infection (CDC), hypotension and hypoglycaemia was associated with fatal outcome. The "presumptive malaria" diagnosis was rejected more frequently in HIV positive (20/31) than in HIV negative patients (2/10, p = 0.023). Conclusion: The study suggests that the fraction of febrile illness attributable to malaria is lower in HIV positive adults. HIV testing should be considered early in evaluation of patients with suspected malaria.