Shock Index and Decreased Level of Consciousness as Terminal Cancer Patients' Survival Time Predictors: A Retrospective Cohort Study.

Abstract

Predicting prognosis using noninvasive and objective tools may facilitate end-of-life decisions for terminal cancer patients, their families, and other health care professionals. To investigate if the shock index (SI), along with decreased level of consciousness (DLOC), is a reliable tool for predicting short-term survival time in terminal cancer patients. A two-part retrospective cohort study was performed on 670 consecutive adult hospice patients. Part 1 of the study was performed to investigate the reliability of SI and DLOC on admission and to make a simple tool for predicting survival time. Part 2 of the study was to validate the tool's reproducibility and analyze the correlation between SI, DLOC, and survival time. In Part 1, multivariate Cox proportional hazards analyses for all study patients revealed that SI ≥ 1.0 in patients with DLOC was a significant risk factor of death (hazard ratio 3.08; 95% CI 1.72-5.53; P = 0.000). Generalized additive models confirmed that DLOC patients with SI = 1.0 had 9.58 days of mean survival time (MST). Receiver operating characteristic curve analyses of SI in patients with DLOC revealed that a survival time of less than three days was most reliably predicted. In Part 2, an increase in SI statistically decreased survival time. The upper 95% CIs of the calculated mean survival time for DLOC patients with SI ≥ 1.0 were less than one week. Bootstrap analyses revealed that the 95% CIs of the predicted survival time were 4.54-6.18 days in DLOC patients with SI = 1.0. An SI ≥ 1.0 along with DLOC is a highly reliable tool for predicting short-term survival time in terminal cancer patients.