Is there any association between body mass index and severity of dengue infection?

Dengue, an acute infectious disease caused by a flavivirus, is a threat to global health. There is sparse evidence exploring obesity and the development of more severe dengue cases in adults. With increasing prevalence of obesity in areas with a high risk of dengue infection, obesity may increase the burden and mortality related to dengue infection. Our study aimed to determine the association between obesity and the development of more severe dengue infection in primary healthcare settings and whether these associations were modified by dengue fever phase.

A cohort study was conducted among laboratory-confirmed dengue patients aged >18 y in the central region of Peninsular Malaysia from May 2016 to November 2017. We collected demographic, clinical history, physical examination and laboratory examination information using a standardized form. Dengue severity (DS) was defined as either dengue with warning signs or severe dengue. Participants underwent daily follow-up, during which we recorded their vital signs, warning signs and full blood count results. Incidence of DS was modeled using mixed-effects logistic regression. Changes in platelet count and hematocrit were modeled using mixed-effects linear regression. The final multivariable models were adjusted for age, gender, ethnicity and previous dengue infection.

A total of 173 patients were enrolled and followed up. The mean body mass index (BMI) was 37.4±13.75 kg/m2. The majority of patients were Malay (65.9%), followed by Chinese (17.3%), Indian (12.7%) and other ethnic groups (4.1%). A total of 90 patients (52.0%) were male while 36 patients (20.8%) had a previous history of dengue infection. BMI was significantly associated with DS (adjusted OR=1.17; 95% CI 1.04 to 1.34) and hematocrit (%) (aβ=0.09; 95% CI 0.01 to 0.16), but not with platelet count (x103/µL) (aβ=-0.01; 95% CI -0.84 to 0.81). In the dose response analysis, we found that as BMI increases, the odds of DS, hematocrit levels and platelet levels increase during the first phase of dengue fever.

Higher BMI and higher hematocrit levels were associated with higher odds of DS. Among those with high BMI, the development of DS was observed during phase one of dengue fever instead of during phase two. These novel results could be used by clinicians to help them risk-stratify dengue patients for closer monitoring and subsequent prevention of severe dengue complications.