Relative seizure reduction was as equally strong a predictor of patient quality of life after epilepsy surgery as seizure freedom in a recent study, with absolute reduction proving to be the worst model surveyed.
Lara Jehi, MD
After an investigation of relative seizure reduction, absolute seizure reduction, and seizure freedom as predictors of quality of life post-epilepsy surgery, study results suggest that relative seizure reduction was as good a predictor of quality of life as seizure freedom on a yes/no scale.1
Study author Lara Jehi, MD, and colleagues explored quality of life in a cohort of 550 patients with epilepsy, each prospectively surveyed before and after surgery, also found that use of a yes/no seizure freedom variable as a measurement of surgery success may be suboptimal in highly complex cohorts such as theirs. This study included a high level of disease severity, with 17% of patients on a repeat surgery, 39% of patients being extratemporal, and 18% being nonlesional.
“Previous work has suggested that seizure outcome is the most important predictor of quality of life after epilepsy surgery, but it is unknown which specific seizure outcome measure should be used in judging surgical success,” Jehi, professor of neurology, Cleveland Clinic Epilepsy Center, and colleagues wrote.
Of the entire cohort, 27% reported having improved quality of life, as measured by Quality of Life in Epilepsy (QOLIE-10) score, despite experiencing persistent seizures. The average improvement in QOLIE-10 score was 5.3 points (95% CI, 4.1—6.5). The mean absolute seizure frequency dropped from 1 per day to 0.1 per day (P <.001), while the mean reduction was 73% (95% CI, 66­—81).
Jehi and coauthors noted that when comparing regression models in order to predict quality of life, the worst model provided occurred when using absolute seizure reduction. Models using relative reduction and seizure freedom were equally strong. Models were compared using adjusted R2 values and Akaike information criteria (AIC).
At the 2019 International Epilepsy Congress, in Bangkok, Thailand, Jehi and colleagues offered another method of predicting post-epilepsy surgery outcomes, an online risk prediction tool that predicts the individualized likelihood of complete seizure freedom at 2 and 5 years post-surgery. Dubbed the Epilepsy Surgery Nomogram, it is a risk predictor built through a thorough analysis of more than 800 patients undergoing the procedure at Cleveland Clinic and validated in a group of more than 600 patients at Mayo Clinic and centers in Brazil, France, and Italy.2
The rate of complete seizure freedom was 57% at 2 years and 40% at 5 years in the original cohort. The validation study showed a nomogram concordance statistic of 0.60 for complete freedom from seizures below the 0.80 threshold of strong concordance.
The Epilepsy Surgery Nomogram used patient gender, pathologic seizure cause, proposed surgery type, presence or absence of generalized tonic-clonic seizures, epilepsy duration, and preoperative seizure frequency to predict its outcomes. In June 2017, the National Institutes of Health (NIH) granted Jehi and colleagues a $3.4-million, 5-year grant to improve the model with additional variables such as EEG and MRI data, family history, and genetic information.3
This enhanced risk calculator is expected to also include a predictor of clinically meaningful improvement in the quality of life post-surgery.
“When completed, this project will generate the first objective, validated, user-friendly epilepsy surgery prediction tool,” Jehi said in a statement at the time of the grant. “We will learn from the collective experience of thousands of patients. Instead of each physician working on an island, we can synthesize data and pull it all together to make more strategic predictions using a much more scientific decision-making process. Achieving this goal will improve patient counseling and benefit public health.”
Quality of life after epilepsy surgery has been a topic of discussion in epilepsy for quite some time, with some recent scientific meetings offering talks and presentations on the topic. One of such work is that of Sarah Wilson, PhD, clinical neuropsychologist, and head, School of Psychological Sciences, University of Melbourne, and colleagues, also presented at IEC 2019. Wilson told NeurologyLive that patients often struggle with the adjustments after surgery, so being able to predict the worsening quality of life can help clinicians get ahead of patients who may be facing challenges.
“If you think about epilepsy surgery, [patients have] been chronically unwell. They have a procedure, and it renders them suddenly better. That’s sometimes described by patients as transformative, so they have this sense of ‘the new me,’ and ‘who am I, now that I don’t have epilepsy?’” she said.
1. Sheikh S, Thompson N, Bingaman W, Gonzalez-Martinez J, Najm I, Jehi L. (Re)Defining success in epilepsy surgery: The importance of relative seizure reduction in patient-reported quality of life. Epilepsia. 2019;60(10):2078-2085. doi: 10.1111/epi.16327.
2. Jehi L, Yardi R, Chagin K, et al. Development and validation of nomograms to provide individualized predictions of seizure outcomes after epilepsy surgery: a retrospective analysis. Lancet Neurol. 2015;14(3):283-90. doi: 10.1016/S1474-4422(14)70325-4.
3. Cleveland Clinic Researcher Receives $3.4 M NIH Grant for Epilepsy Surgery Research [press release]. Cleveland, OH: Cleveland Clinic; Published June 27, 2017. newsroom.clevelandclinic.org/2017/06/29/cleveland-clinic-researcher-receives-3-4-m-nih-grant-for-epilepsy-surgery-research. Accessed October 15, 2019.