Association of body mass index with COVID-۱۹ outcome in a pediatric tertiary referral hospital in Iran

One of the challenging risk factors for severe COVID-۱۹ infection is body mass index (BMI). It was reported that overweight and obese patients are at a higher risk of developing severe COVID-۱۹ infection and its complications. Obesity also worsens the prognosis of COVID-۱۹ in adults and increases the mortality rate in younger patients. In addition, obesity is the most important risk factor for chronic disorders and metabolic syndromes in adults, but pediatric chronic diseases are usually related to congenital and developmental problems. The BMI of children with underlying comorbidities is affected by secondary malnutrition, dwarfism, and drugs. In this study we assessed the association of BMI with clinical outcomes of COVID-۱۹ infection (ICU admission, death, and ventilator requirement) in hospitalized pediatric patients in Iran. This retrospective cross-sectional study was performed in the biggest referral pediatric hospital in Tehran from March ۷ to August ۱۷, ۲۰۲۰. All hospitalized children <۱۸ years of age with laboratory-confirmed COVID-۱۹ were included in the study. We evaluated the association of BMI with COVID-۱۹ outcomes (death, severity of clinical course, oxygen therapy, intensive care unit [ICU] admission, ventilator requirement). The secondary objectives were investigating the association of gender, underlying comorbidity, and patient age with COVID-۱۹ outcomes. The limits for obesity, overweight, and underweight were set at BMI ۹۵ percentile, ۸۵ ≤ BMI < ۹۵, and BMI ۵ percentile, respectively. Results In total, ۱۸۹ confirmed pediatric cases of COVID-۱۹ (۰.۱-۱۷ years) with a mean age of ۶.۴ ± ۴.۷ years were included. Overall, ۱۸.۵% of the patients were obese and ۳۳% were underweight. We found that BMI had no significant relation with COVID outcomes in pediatric cases but after subgrouping the participants, underlying comorbidities and lower BMI in previously ill children were independently associated with a poor clinical outcome of COVID-۱۹. In addition, the previously ill children with higher BMI percentiles were at a relatively lower risk of ICU admission (۹۵% CI: ۰.۹۷۱-۰.۹۹۸, OR: ۰.۹۸, p = ۰.۰۲۵) and better clinical course of COVID-۱۹ (۹۵% CI: ۰.۹۷۰-۰.۹۹۶, OR: ۰.۹۸, p = ۰.۰۰۹). The BMI percentile had a statistically significant direct relationship with age. Based on our results, obesity is not related to COVID-۱۹ outcomes in pediatric patients, but after controlling for confounding effects, underweight in children with underlying comorbidities was more likely to be associated with a poor prognosis of COVID-۱۹.