Validation of the Clinical Index of Stable Febrile Neutropenia (CISNE) model in febrile neutropenia patients visiting the emergency department. Can it guide emergency physicians to a reasonable decision on outpatient vs. inpatient treatment?

Abstract

Advances in oncology have enabled physicians to treat low-risk febrile neutropenia (FN) in outpatient settings. This study was aimed to explore the usefulness of the CISNE model and identify better triage in the emergency setting. This is a retrospective cohort study on 400 adult FN patients presenting to the Emergency Department of National Cancer Center, Korea from January 2010 to December 2016. All had been treated with cytotoxic chemotherapy for solid tumors in the previous 30 days. The primary outcome was the frequency of any serious complications during the duration of illness. Apparently stable patients numbered 299 (74.8%) of 400, and the remainder comprised clinically unstable patients. The stable patients fell into three cohorts according to the risk scores: CISNE I (low risk), 56 patients (18.7%); CISNE II (intermediate), 124 (41.5%) and CISNE III (high), 119 (39.8%). The primary outcome occurred in 10.7%, 19.4% and 33.6%, respectively, according to the cohort. Compared with the Multinational Association of Supportive Care in Cancer Risk Index Score (MASCC RIS), CISNE I stratum had significantly lower sensitivity (0.22 vs. 0.95 of MASCC low risk) but higher specificity (0.91 vs. 0.17) to predict zero occurrence of the primary outcome. The CISNE model was useful for identifying low-risk FN patients for outpatient treatment. The combination of the CISNE and MASCC RIS may help emergency physicians cope with FN more confidently.

Fig 1. Study scheme.

Two key conditions screened 1,168 patients who visited the emergency department from January 01, 2010 to December 31, 2016: a body temperature on arrival greater than 37.5°C and an absolute neutrophil count smaller than 1000/mm³. The study finally enrolled 400 patients for analysis after excluding those who met any of exclusion criteria as illustrated. BT, body temperature; ANC, absolute neutrophil count; PTE, pulmonary thromboembolism; ASP, apparently stable patients; CUP, clinically unstable patients.

Fig 2. A chart showing the frequencies of acute complications that destabilized febrile neutropenia patients at the emergency department.

% indicates the proportion of the entire patients (N = 400). “Decompensation” indicates decompensation of preexisting comorbidities. PTE, pulmonary thromboembolism; DIC, disseminated intravascular coagulopathy; AKI, acute kidney injury.

Fig 3. Receiver operating characteristic (ROC) analysis with respect to the MASCC score and CISNE score.

Each variable’s AUC was 0.66 (95% CI; 0.60–0.71) and 0.64 (95% CI; 0.59–0.70), respectively. The difference between areas was 0.02 (95% CI;-0.08–0.11) and not statistically significant (P = 0.71).