We read with great interest the outstanding study by Desai et al. (1) in the recent issue of Diabetes Care. The authors aimed to determine the incidence and costs of hospitalizations for diabetes ketoacidosis (DKA) in the U.S. The authors searched the National Inpatient Sample (NIS) database for all DKA admissions during 2003-2014. Consistent with recent Centers for Disease Control and Prevention reports (2), the study confirmed a decrease in hospital mortality but a significant increase in the number of hospitalizations for DKA. Notably, they reported a significant increase (56%) in the "inflation-adjusted hospital charges" for DKA admissions, from $18,987 in 2003 to $26,566 in 2014 (P , 0.001). Thus, the inflation-adjusted "national bill" for DKA hospitalization was estimated to be $5.1 billion in 2014. It is noteworthy that the authors used the terms "charges" and "costs" interchangeably in the abstract and article. Extensive evidence supports that hospital charges should not be used as a direct estimate of the cost of hospital care (3-5). For instance, hospital charges, defined as the amount billed by hospitals for the services rendered, do not actually reflect hospital costs, defined as how much the hospital service actually costs or was paid to the hospital. Hospital costs are the actual expenses incurred by hospitals in rendering the service, including wages, supplies, and utility