Abstracts

Rationale: "Hospital crossover" occurs when people visit multiple hospitals for care. Such crossover may cause recent, relevant clinical data to be missing from the electronic health record at the time of care, potentially denying physicians access to important patient information. Crossover is common among people with epilepsy -- we previously found a quarter of people with epilepsy engaged in hospital crossover over two years. However, the effect of crossover on subsequent use of health services is unknown. Understanding this effect will help prioritize healthcare delivery innovations targeted for this population. Methods: We examined the effect of baseline hospital crossover in one year on subsequent use of health services in the following year, among people with epilepsy, using a retrospective cohort study design. To do so, we assembled a de-identified database from a health information exchange network. The database included 7918 people with epilepsy who visited any of seven hospitals in New York, NY from 2009-2012. Data included demographics, comorbidities, and two years of visit information from ambulatory, inpatient, emergency, and radiology settings. We performed two complimentary analyses, in order to (1) illustrate the effect on a carefully selected subgroup, and (2) confirm the effect across the study population. First, we performed a matched cohort analysis on 414 pairs of individuals with and without hospital crossover in the baseline year. We matched individuals exactly on 7 variables, and used propensity score matching to balance the remaining 36 variables. Second, we performed a propensity score odds weighted ordinal logistic regression analysis to estimate the effect across all 7918 individuals. The outcomes were the use of six health services in the follow-up year. Results: In the matched pair analysis, baseline hospital crossover increased the odds of more visits in the ED (odds ratio [95%CI] 1.48 [1.08,2.03]) and radiology settings (1.96 [1.4,2.78]), including more brain MRIs (3.25 [1,13.7]). The regression analysis confirmed these findings, and also indicated crossover lead to more inpatient admissions (1.35 [1.12,1.64]) and head CTs (1.41 [1.02,1.96]). (Table) Conclusions: Baseline hospital crossover is an independent marker for increased health service use in multiple settings among people with epilepsy. The pattern of increased use (more ED, inpatient, and radiology use; more head CTs) among people with hospital crossover suggests crossover may be associated with inadequate outpatient care. Healthcare delivery innovations targeted for people with epilepsy who engage in hospital crossover should prioritize (1) sharing radiology images and reports (to reduce unnecessary radiology use), and (2) improving coordination of care (to reduce unnecessary ED and inpatient use). Of note, this study highlights health information exchange networks as an emerging source of information about people with epilepsy, aligning with the Institute of Medicine's recent recommendation to develop new data sources for epilepsy research.