At. Berg et al., MULTIVARIABLE PREDICTION OF SEIZURE OUTCOME ONE-YEAR AFTER RESECTIVE EPILEPSY SURGERY - DEVELOPMENT OF A MODEL WITH INDEPENDENT VALIDATION, Epilepsy research, 29(3), 1998, pp. 185-194
Purpose: To identify predictors of seizure-outcome after epilepsy surg
ery and validate the findings in an independent series of patients. To
use the results to develop a predictive model. Methods: Sequential pa
tients undergoing resective surgery for medically intractable epilepsy
were identified at Yale New Haven Hospital (1987-1990, group 1) and C
olumbia Presbyterian Hospital (1991-1994, group 2). Information about
seizure outcome and predictors of outcome was obtained from medical ch
art review. Good seizure-outcome was defined as having been seizure-fr
ee for one year beginning with discharge from the hospital. Multiple l
ogistic regression was used to develop a model of predictors in group
1. It was then validated in group 2. Results: There were 133 patients
in group 1 and 81 in group 2. In a multivariable analysis, independent
predictors of outcome in group 1 were presence of mesial temporal scl
erosis based on postsurgical pathological analysis (MTS) (relative ris
k (RR) = 1.47), having a known underlying etiology (RR = 1.32), and pa
rtial seizures only (RR = 1.17). In group 2, the findings for each fac
tor were similar to those in group 1: MTS, RR = 1.49; etiology, RR = 1
.32; and partial seizures, RR = 1.24. Used in combination, these three
factors can identify patients with nearly a 100% chance of being seiz
ure-free (all three factors present) versus less than a 50% chance (no
ne of the three factors present). Conclusions: With independent valida
tion of the findings, we can be reasonably certain that the three fact
ors identified in this analysis are meaningful and generalizable predi
ctors of seizure outcome following epilepsy surgery. Use of predictive
models should be considered in future studies to convert study result
s into clinically relevant statements about a particular patient's lik
elihood of surgical success. (C) 1998 Elsevier Science B.V. All rights
reserved.