MRI in acutely ill medical patients in an Irish hospital: influence on outcomes and length of hospital stay.

PURPOSE: MRI is an important diagnostic tool for acute medical admissions. Its relevance to in-hospital mortality and length of stay (LOS) has been examined at St James's Hospital in Dublin, Ireland.

METHODS: All patients admitted for medical emergencies from 2010 through 2012 were studied (18,534 episodes); any relationship between an MRI request, underlying diagnosis on any in-hospital death, and LOS was examined. Logistic regression with generalized estimating equations, adjusted for correlated observations (readmissions), odds ratio estimates, and zero-truncated Poisson regression for LOS were used.

RESULTS: MRI procedures were requested in 8.6% of episodes. The in-hospital mortality rate was significantly higher when MRI was performed (7.8% vs 4.6%, P < .001). The unadjusted odds ratio for in-hospital death during that episode was 1.74 (95% confidence interval, 1.26-2.37; P < .001) compared with episodes without MRI. The hospital stay for those MRI episodes was longer (median, 9.1 days; interquartile range, 4.0-26.8 days) than for non-MRI episodes (median, 5.8 days; interquartile range, 2.2-12.2; P < .001). Each unit increase in MRI waiting time (cutoffs set at 0, 1, 3, 7, and 14 days) gave an estimated increase of 1.12 days in hospital LOS, adjusted for illness severity and comorbidities.

CONCLUSIONS: MR imaging identified in a subgroup of emergency patients at higher risk of an in-hospital death. These patients have longer LOS attributable in part to procedure wait times, not merely to illness severity or comorbidities.