Clinical prediction model to identify vulnerable patients in ambulatory surgery: towards optimal medical decision-making.
BACKGROUND
Ambulatory surgery patients are at risk of adverse psychological outcomes such as anxiety, aggression, fatigue, and depression. We developed and validated a clinical prediction model to identify patients who were vulnerable to these psychological outcome parameters.


METHODS
We prospectively assessed 383 mixed ambulatory surgery patients for psychological vulnerability, defined as the presence of anxiety (state/trait), aggression (state/trait), fatigue, and depression seven days after surgery. Three psychological vulnerability categories were considered-i.e., none, one, or multiple poor scores, defined as a score exceeding one standard deviation above the mean for each single outcome according to normative data. The following determinants were assessed preoperatively: sociodemographic (age, sex, level of education, employment status, marital status, having children, religion, nationality), medical (heart rate and body mass index), and psychological variables (self-esteem and self-efficacy), in addition to anxiety, aggression, fatigue, and depression. A prediction model was constructed using ordinal polytomous logistic regression analysis, and bootstrapping was applied for internal validation. The ordinal c-index (ORC) quantified the discriminative ability of the model, in addition to measures for overall model performance (Nagelkerke's R (2) ).


RESULTS
In this population, 137 (36%) patients were identified as being psychologically vulnerable after surgery for at least one of the psychological outcomes. The most parsimonious and optimal prediction model combined sociodemographic variables (level of education, having children, and nationality) with psychological variables (trait anxiety, state/trait aggression, fatigue, and depression). Model performance was promising: R (2)  = 30% and ORC = 0.76 after correction for optimism.


CONCLUSIONS
This study identified a substantial group of vulnerable patients in ambulatory surgery. The proposed clinical prediction model could allow healthcare professionals the opportunity to identify vulnerable patients in ambulatory surgery, although additional modification and validation are needed. (ClinicalTrials.gov number, NCT01441843).
Department of Anesthesiology, Erasmus University Medical Center, Room HS-203, PO Box 2040, 3000 CA, Rotterdam, The Netherlands. h.mijderwijk@erasmusmc.nl.
Herjan
H
Mijderwijk
Department of Anesthesiology, Erasmus University Medical Center, Room HS-203, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
Robert Jan
RJ
Stolker
Department of Anesthesiology, Erasmus University Medical Center, Room HS-203, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
Hugo J
HJ
Duivenvoorden
Department of Anesthesiology, Erasmus University Medical Center, Room HS-203, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
Markus
M
Klimek
Department of Public Health, Erasmus University Medical Center, Rotterdam, The Netherlands.
Ewout W
EW
Steyerberg
D000328:Adult; D000368:Aged; D000374:Aggression; D000556:Ambulatory Surgical Procedures / Q000379:methods*; D001007:Anxiety / Q000175:diagnosis / Q000523:psychology; D015992:Body Mass Index; D000066491:Clinical Decision-Making / Q000379:methods*; D003863:Depression / Q000175:diagnosis / Q000523:psychology; D005221:Fatigue / Q000175:diagnosis / Q000523:psychology; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011183:Postoperative Complications / Q000175:diagnosis / Q000517:prevention & control; D011237:Predictive Value of Tests; D011446:Prospective Studies; D018570:Risk Assessment / Q000379:methods*; D012959:Socioeconomic Factors; D055815:Young Adult