Background: About 209,000 adults experience an in-hospital cardio-pulmonary arrest (IHCA) every year in the US. Known early warning scoring systems (e.g., MEWS, eCART) have shown low efficiency in predicting a patient’s risk of deterioration. We assessed the possibility of using the Rothman Index (RI) as such a tool.

Methods: We conducted a retrospective case-control study with 248 adult inpatients at Yale-New Haven Hospital. The IHCA group was comprised of  124 patients who had experienced an IHCA between February 2013 and September 2014. The 124 control group patients did not have an IHCA and were matched by date and time of hospitalization, level of care and principal diagnosis. Patients’ RI scores on admission (first RI) and during the 48 hours preceding the IHCA time were used. A mixed linear model statistic and change-point analysis were used to compare RI trend by group.

Results: Baseline characteristics (age, gender, first documented RI) did not significantly differ by group. The final regression model (p=0.022), adjusted for first RI and principal diagnosis, showed significantly lower RI scores in IHCA group beginning at 46 hours and 8 hours before IHCA for ICU and non-ICU patients, respectively. The change point analysis of RI scores trend in IHCA group showed a significant breaking point in the RI scores’ declining trend at 2 and 3 hours before IHCA in non-ICU and ICU patients, respectively.

Conclusions: The changes in the RI scores over time showed a significant discrimination in patients who developed IHCA. Our results suggests that the RI may be used as an ancillary tool in inpatient clinical management.