Clostridium difficile infection as a novel marker for hospital quality, efficiency and other factors associated with prolonged inpatient length of stay

Excess inpatient length of stay (LOS) varies between hospitals and is burdensome to patients and the overall healthcare system. Variation in LOS has often been associated with hospital-level factors, such as hospital e ciency and quality. Clostridium di cile infection (CDI) is an increasingly common hospital-acquired (HA) infection. This thesis explores the connection between hospital incidence of CDI and excess LOS in patients without a CDI. It is hypothesized that HA-CDI incidence may act as a “proxy variable” to capture unobserved hospital characteristics, such as hospital quality or e ciency, associated with prolonged LOS. In addition, hospitals with longer LOS may tend to observe more HA-CDI cases prior to discharge. This thesis analyzes the ability of CDI incidence to capture excess LOS variation across hospitals, while controlling for CDI cases that occur after discharge. We use data on hospital inpatient visits, spanning the years 2005-2011, from three data sources distributed by the Healthcare Cost and Utilization Project: the Nationwide Inpatient Sample (NIS), and the State Inpatient Databases (SID) for California and New York. The NIS provides discharge records from a nationwide sampling of hospitals in a given year. The SIDs are longitudinal populations of inpatient records in each state, and patient records can be linked across stays. We compute a variety of di↵erent measures of hospital CDI incidence and identify HACDI cases that occur after a patient is discharged. Various multivariable regression models are analyzed to predict LOS at an