Predictive Value of Rothman Index in Patients That Develop Febrile Neutropenia

Background: Febrile Neutropenia (FN) in cancer patients is associated with a high mortality rate yet identifying patients with FN at highest risk for short term morbidity and mortality remains challenging. The Rothman Index (RI) is a real-time composite measurement of a patient’s condition using 26 clinical variables sensitive to signs of patient clinical decline. RI has been shown to predict intensive care unit (ICU) admission, hospital readmission and short term mortality among inpatients. A prior study from our institution demonstrated that hospitalized patients with hematological malignancies and RI < 60 have a greater likelihood of readmission or discharge to hospice rather than those with higher RI scores. The aim of this study was to explore RI as a predictor of adverse outcomes in patients with hematological malignancies who have FN.

Methods: Chart records of all patients with hematological malignancies and FN who were hospitalized at Yale Cancer Center between February of 2013 and July of 2014 were reviewed. Clinical variables collected included demographics, malignancy type, comorbidities, admission condition and microbiological data related to the FN episode. The primary outcome measure was a composite of in-hospital mortality and discharge to hospice care.  Variables associated with the primary outcome in univariate analysis were entered into a multivariate logistic regression model for analysis. 

Results: Of 308 patients with hematological malignancies, 180 (58.4%) developed FN during their admission and 38 (12.3%) died during the admission or were discharged to hospice. A total of 85 (27.6%) patients had a RI < 60, 155 (50.3%) had a RI between 60-80, and 71 (23.1%) had a RI > 80. Controlling for malignancy type, major medical comorbidities and microbiologically confirmed bacterial infection, RI < 60 was independently associated with this outcome (Odds ratio 3.02, 95% Confidence Interval 1.25-7.34).  Baseline renal disease, pneumonia, respiratory failure and sepsis were also associated with the primary outcome.

Conclusion: RI is an objective measure that can independently predict poor outcomes among inpatients with FN.  RI can guide clinicians caring for patients with FN in both prognostication and identifying high risk patients with an RI < 60 who are at higher risk for mortality, discharge to hospice, or high risk of readmission. The utility of this scoring system should be compared to existing risk stratification systems used in Oncology to identify its optimal use in the clinical setting. 

Table. Factors associated with inpatient mortality or hospice discharge among hematologic malignancy inpatients with febrile neutropenia  

Variable	OR	95% CI for OR	p
RI < 60	3.02	1.25-7.34	.015
Respiratory Failure	3.51	1.07-11.56	.039
Renal Disease	4.97	1.38-17.9	.014
Sepsis	8.18	1.63-41.2	.011
Pneumonia	8.01	1.42-45.1	.018