Is surgical volume still the most accurate indicator of blood usage in the United States?

Abstract

Estimates of blood collection and use in the United States derived from the National Blood Collection and Utilization Survey (NBCUS) call for application of robust statistical methods in the analysis of survey data. Since 1993, annual inpatient surgical volume has been used as the main stratification variable for sampling and estimation. However, recent NBCUS results have shown a decrease in blood use in surgical settings, raising the possibility that inpatient surgical volume may no longer be the optimal stratification variable. The objective of this study is to explore factors affecting hospital blood utilization. A multivariate generalized linear regression with a negative binomial distribution was used to determine which hospital characteristics best explained allogeneic red blood cell (RBC) use, using data from the 2015 NBCUS to determine hospital blood use and the 2013 annual American Hospital Association database to identify hospital characteristics. Annual inpatient surgical volume explained the most variation in allogeneic RBC use among hospitals (pseudo-R2 of 70.8%). Additional variables, such as presence of an oncology service, were also statistically significant in the models but explained little additional variability in blood use. These findings suggest that annual inpatient surgical volume is an appropriate indicator for estimating blood utilization in the United States. As trends in blood utilization continue to evolve, ongoing analytic efforts to understand indicators of blood use are necessary.