Age as a Risk Factor for Severe Manifestations and Fatal Outcome of Falciparum Malaria in European Patients: Observations from TropNetEurop and SIMPID Surveillance Data

Abstract

Previous studies have indicated that age is a risk factor for severe falciparum malaria in nonimmune patients. The objectives of this study were to reevaluate previous findings with a larger sample and to find out how strongly clinical outcomes for elderly patients differ from those for younger patients. Results of adjusted analyses indicated that the risks of death due to falciparum malaria, of experiencing cerebral or severe disease in general, and of hospitalization increased significantly with each decade of life. The case-fatality rate was almost 6 times greater among elderly patients than among younger patients, and cerebral complications occurred 3 times more often among elderly patients. Antimalarial chemoprophylaxis was significantly associated with a lower case-fatality rate and a lower frequency of cerebral complications. Women were more susceptible to cerebral complications than were men. Our study provides evidence that falciparum malaria is more serious in older patients and demonstrates that clinical surveillance networks are capable of providing quality data for investigation of rare events or diseases.

Chemoprophylaxis and Malaria Death Rates

“…We are not aware of any such association being reported. Yet the findings are consistent with earlier reports ( 9 , 12 ). Our findings are also in line with observations made in numerous case reviews in which severity of illness appeared to be lower among patients who had taken chemoprophylaxis compared to patients who had not ( 13 – 15 ).…”

“…Age has been identified as a risk factor for severe disease or fatal outcome of malaria in several studies and case reports from the United States, Europe, and Israel ( 8 , 9 , 12 , 15 , 16 , 22 , 23 ). In contrast to those previous studies, we decided not to group the age into categories because our study population was sufficiently large to use age as a continuous variable, which allowed us to avoid any kind of classification bias.…”

“…Our findings confirmed that the risk of dying from malaria increases with age (OR 1.06, 95% CI 1.04–1.07). As discussed by Mühlberger et al, the most likely explanation for the observed age effect is that with increasing age the immune system looses its capacity to generate a competent immune response against previously unencountered pathogens ( 12 ). Our study adds an important conclusion to this finding: although the elderly have an increased risk of dying from malaria, they can significantly reduce this risk by taking chemoprophylaxis.…”

“…Both variables serve as a proxy for non-immunity and have been used as such in previous studies ( 12 , 15 ). During a transition period from 1999 to 2000, nationality and country of birth were simultaneously assessed in our surveillance system, and a comparison of both variables showed that the discrepancy was ≈5%.…”

Severe Imported Malaria in a Serbian Referral Center

“…Many studies have shown that increasing age is a risk factor for severe malaria although some authors have questioned this view [29][30][31][32][33]. The average age of patients with severe malaria in this study was approximately 44 years and statistical analysis lead us to the conclusion that old age was not a risk factor for severe malaria.…”