Obesity and Diabetes as Risk Factors for Severe Plasmodium falciparum Malaria: Results From a Swedish Nationwide Study

Background Noncommunicable diseases and obesity are increasing in prevalence globally, also in populations at risk of malaria. We sought to investigate if comorbidity, in terms of chronic diseases and obesity, is associated with severe Plasmodium falciparum malaria. Methods We performed a retrospective observational study in adults (≥18 years of age) diagnosed with malaria in Sweden between January 1995 and May 2015. We identified cases through the surveillance database at the Public Health Agency of Sweden and reviewed clinical data from 18 hospitals. Multivariable logistic regression was used to assess associations between comorbidities and severe malaria. Results Among 937 adults (median age, 37 years; 66.5% were male), patients with severe malaria had higher prevalence of chronic diseases (28/92 [30.4%]) compared with nonsevere cases (151/845 [17.9%]) (P = .004). Charlson comorbidity score ≥1 was associated with severe malaria (adjusted odds ratio [aOR], 2.63 [95% confidence interval {CI}, 1.45-4.77), as was diabetes among individual diagnoses (aOR, 2.98 [95% CI, 1.25-7.09]). Median body mass index was higher among severe (29.3 kg/m2) than nonsevere cases (24.7 kg/m2) (P < .001). Obesity was strongly associated with severe malaria, both independently (aOR, 5.58 [95% CI, 2.03-15.36]) and in combination with an additional metabolic risk factor (hypertension, dyslipidemia, or diabetes) (aOR, 6.54 [95% CI, 1.87-22.88]). The associations were observed among nonimmune travelers as well as immigrants from endemic areas. Conclusions Comorbidities, specifically obesity and diabetes, are previously unidentified risk factors for severe malaria in adults diagnosed with P. falciparum. Noncommunicable diseases should be considered in the acute management and prevention of malaria.