Globally, both obesity and underweight are severe health risks for various diseases. The current study systematically examined the emerging evidence to identify an association between body mass index (BMI) and COVID-19 disease outcome. Online literature databases (e.g., Google Scholar, PubMed, MEDLINE, EMBASE, Scopus, Medrixv and BioRixv) were screened following standard search strategy having the appropriate keyword such as "Obesity", "Underweight", "BMI", "Body Mass Index", "2019-nCov", "COVID-19, "novel coronavirus", "coronavirus disease". Studies published till 20(th) April 2020 were included without language restriction. These studies include case reports, case series, cohort, and any other which reported BMI, overweight/obesity or underweight, and its complication with COVID-19 disease. This study observed COVID-19 infection among BMI < 25 kg/m(2) with prevalence of 0.60 (95%CI: 0.34-0.86, I(2) = - 76.77) as compared to the 0.34 (95%CI: 0.23-0.44, I(2) = 53.45% heterogeneity) having BMI > 25 kg/m(2). The results of the current study show that BMI plays a significant role in COVID-19 severity in all age groups, especially the older individuals. A panel of doctors and nursing staff should review COVID-19 patients with higher BMI with other co-morbidities (diabetes and hypertension), and they should be given increased vigilance, priority in testing, and treatment to control the associated co-morbidities. Further, the COVID-19 patients whose illness entered 7-10 days, age > 50 years, and elevated CRP levels should be given additional medical considerations. Our finding showed that the population and patients with high BMI have moderate to high risk of medical complications with COVID-19, and hence, their health status should be monitored more frequently including monitoring of blood pressure and blood glucose.
All age groups Risk group Risk factor COVID-19