Development of a Likelihood of Survival Scoring System for Hospitalized Equine Neonates Using Generalized Boosted Regression Modeling

Abstract

BackgroundMedical management of critically ill equine neonates (foals) can be expensive and labor intensive. Predicting the odds of foal survival using clinical information could facilitate the decision-making process for owners and clinicians. Numerous prognostic indicators and mathematical models to predict outcome in foals have been published; however, a validated scoring method to predict survival in sick foals has not been reported. The goal of this study was to develop and validate a scoring system that can be used by clinicians to predict likelihood of survival of equine neonates based on clinical data obtained on admission.Methods and ResultsData from 339 hospitalized foals of less than four days of age admitted to three equine hospitals were included to develop the model. Thirty seven variables including historical information, physical examination and laboratory findings were analyzed by generalized boosted regression modeling (GBM) to determine which ones would be included in the survival score. Of these, six variables were retained in the final model. The weight for each variable was calculated using a generalized linear model and the probability of survival for each total score was determined. The highest (7) and the lowest (0) scores represented 97% and 3% probability of survival, respectively. Accuracy of this survival score was validated in a prospective study on data from 283 hospitalized foals from the same three hospitals. Sensitivity, specificity, positive and negative predictive values for the survival score in the prospective population were 96%, 71%, 91%, and 85%, respectively.ConclusionsThe survival score developed in our study was validated in a large number of foals with a wide range of diseases and can be easily implemented using data available in most equine hospitals. GBM was a useful tool to develop the survival score. Further evaluations of this scoring system in field conditions are needed.

Evaluation of updated sepsis scoring systems and systemic inflammatory response syndrome criteria and their association with sepsis in equine neonates

“…The reason for this difference between groups is not known, but the higher respiratory rate in healthy foals could be a consequence of excitement or anxiety in response to restraint and physical examination. The only variable that was statistically different between the septic group and the sick‐nonseptic and healthy groups in our study was a lower WBC count in the septic group, previously associated with nonsurvival in neonatal foals …”

Factors associated with outcome and gradual improvement in survival over time in 1065 equine neonates admitted to an intensive care unit

“…Factors associated with outcome using multivariable analyses in prior studies have varied considerably and include cold extremities, recumbency, suckle reflex, temperature, heart rate, age, gestation <320 days, ≥2 infection sites, IgG, glucose, creatinine, WBC or neutrophils and anion gap [3,4,11,12]. Some of these factors, such as temperature and neutrophils were significantly associated with both nonsurvival and natural death in the current study.…”

“…In addition, bacteraemia, bicarbonate, PCO 2 , presence of infectious orthopaedic disorders, presence of other disorders and sepsis score were significantly associated with nonsurvival in this study. Models to predict outcome in equine neonates have suboptimal predictive values and should not be used as the sole criterion on which to base a decision for euthanasia [11,12]. Lactate was not included in the data analysis in this study because it was only available for foals admitted during the last decade.…”

Evaluation of the foal survival score in a Danish‐Swedish population of neonatal foals upon hospital admission

“…Sepsis was defined as ≥1 of the following: (1) positive blood culture; (2) evidence of localized infection and systemic inflammatory response syndrome (SIRS, Supporting Information 1); (3) sepsis score ≥12; or, (4) presence of multiple infectious sites on necropsy. The FSS was calculated as previously reported (Table ) …”

“…For mixed populations of critically ill equine neonates, several models for predicting survival have been developed using historical, clinical, and laboratory variables . Two predictive equations for estimating survival have been published previously.…”