Customized Prediction of Short Length of Stay Following Elective Cardiac Surgery in Elderly Patients Using a Genetic Algorithm.
OBJECTIVE
To develop a customized short LOS (<6 days) prediction model for geriatric patients receiving cardiac surgery, using local data and a computational feature selection algorithm.


METHODS
Utilization of a machine learning algorithm in a prospectively collected STS database consisting of patients who received cardiac surgery between January 2002 and June 2011.


METHODS
Urban tertiary-care center.


METHODS
Geriatric patients aged 70 years or older at the time of cardiac surgery.


METHODS
None.


RESULTS
Predefined morbidity and mortality events were collected from the STS database. 23 clinically relevant predictors were investigated for short LOS prediction with a genetic algorithm (GenAlg) in 1426 patients. Due to the absence of an STS model for their particular surgery type, STS risk scores were unavailable for 771 patients. STS prediction achieved an AUC of 0.629 while the GenAlg achieved AUCs of 0.573 (in those with STS scores) and 0.691 (in those without STS scores). Among the patients with STS scores, the GenAlg features significantly associated with shorter LOS were absence of congestive heart failure (CHF) (OR = 0.59, p = 0.04), aortic valve procedure (OR = 1.54, p = 0.04), and shorter cross clamp time (OR = 0.99, p = 0.004). In those without STS prediction, short LOS was significantly correlated with younger age (OR = 0.93, p < 0.001), absence of CHF (OR = 0.53, p = 0.007), no preoperative use of beta blockers (OR = 0.66, p = 0.03), and shorter cross clamp time (OR = 0.99, p < 0.001).


CONCLUSIONS
While the GenAlg-based models did not outperform STS prediction for patients with STS risk scores, our local-data-driven approach reliably predicted short LOS for cardiac surgery types that do not allow STS risk calculation. We advocate that each institution with sufficient observational data should build their own cardiac surgery risk models.
School of Public Health and Health Systems, University of Waterloo, Waterloo, Canada ; Harvard-MIT Division of Health Sciences and Technology, Cambridge, USA.
Joon
J
Lee
Beth Israel Deaconess Medical Center, Boston, USA.
Sapna
S
Govindan
Harvard-MIT Division of Health Sciences and Technology, Cambridge, USA ; Beth Israel Deaconess Medical Center, Boston, USA.
Leo A
LA
Celi
Beth Israel Deaconess Medical Center, Boston, USA.
Kamal R
KR
Khabbaz
Beth Israel Deaconess Medical Center, Boston, USA.
Balachundhar
B
Subramaniam
Cardiac Surgery; Elderly; Genetic Algorithm; Length of Stay; Risk Prediction