The role of metabolic comorbidity in COVID-19 mortality of middle-aged adults. The case of Mexico

BackgroundIn contrast to developed countries, in Mexico more than half of COVID-19 deaths have occurred in adults MethodsTo explore what contributes to the high COVID-19 mortality in Mexican middle-aged adults, we calculated age-stratified COVID-19 case fatality rates, YLL and relative risk (RR) of 9 comorbidities and 23 comorbidity combinations in a retrospective Mexican cohort with 905,579 PCR-confirmed COVID-19 cases/89,167 deaths, until Nov/2/2020.FindingsChronic kidney disease (CKD) had the highest RR for COVID-19 fatality, followed by diabetes and immunosuppression, that in turn had higher RR than obesity or hypertension as single comorbidities. The combination diabetes/hypertension with or without obesity had RR as high as CKD as a single comorbidity (>3 in ConclusionsThe Mexican COVID-19 outbreak illustrates that middle-aged adults 45-64-yo can have high COVID-19 mortality during large outbreaks, especially if they present chronic metabolic comorbidities, but also in their absence, making them an important group of concern after elders. COVID-19 mortality in middle-aged adults is likely proportional to the gradual decline in health that accompanies ageing, which presents earlier in poorer populations that also get more exposed to SARS-CoV-2 and have less access to specialized medical attention.