Patients Imaged Early During Admission Demonstrate Reduced Length of Hospital Stay: A Retrospective Cohort Study of Patients Undergoing Cross-Sectional Imaging

Purpose: The aim of this study was to relate the early use of advanced imaging to length of hospital stay. Materials and Methods: Among all 33,226 admissions to an urban tertiary care hospital in 2005, the authors identified the 10,005 admissions (30.1%) that included >= 1 advanced imaging study (CT, MRI, or nuclear scintigraphy) during the period from 1 day before admission (day -1) through discharge. The length of stay was calculated, and using the date of the first advanced imaging study performed relative to date of admission (date of service), the residual length of stay (length of stay minus date of service) of each admission was also calculated. For admissions of >= 3 days in duration, the mean length of stay of patients with early imaging (on day -1 or 0) was compared using t test to that of patients with later imaging (on day 1 or 2). For all admissions with advanced imaging, linear regression analysis was applied to length of stay and residual length of stay as a function of date of service. Similar analysis was performed on subgroups classified by examination type (modality and body part) and International Classification of Diseases, Ninth Revision (ICD-9) diagnostic code. Results: The mean length of stay was significantly shorter for those imaged on day -1 or 0 compared with day 1 or 2 for all admissions of >= 3 days (8.6 vs 9.0 days, P = .015) and for the following specific subgroups: abdominal CT (8.4 vs 9.7 days, P = .003) and neurologic MR examination types (7.6 vs 8.7 days, P = .03) and abdominal ICD-9 codes (7.5 vs 8.8 days, P = .007). A statistically significant positive correlation was noted between length of stay and date of service for all admissions (slope, 0.27; P < .001) and for the following subgroups: neurologic CT, chest CT, abdominal CT, and nuclear scintigraphy examination types and abdominal ICD-9 codes. Conclusion: Early imaging with CT, MRI, or nuclear scintigraphy, particularly on the day before or the day of admission, was associated with significantly shorter lengths of stay of inpatients compared with patients who underwent advanced imaging later.