Epilepsy surgery and meaningful improvements in quality of life: results from a randomized controlled trial

Abstract

Objective: We examine improvement and worsening in quality of life (QOL) in terms of proportions achieving minimum clinically important change (MCID), and factors related to MCID, in patients with temporal lobe epilepsy randomized to medical or surgical treatment.

Methods: Eighty patients with temporal lobe epilepsy randomized to surgical (n(1) = 40) or medical (n(2) = 40) therapy were followed for 12 months, reporting QOL at baseline, and at 6 and 12 months. Previously established thresholds for MCID across various general and epilepsy-specific QOL instruments were used to determine meaningful improvement (positive MCID) or worsening (negative MCID). Generalized linear mixed-effects models were used to compare MCID in both groups.

Results: At 6 months, 56.0% of patients in the surgical group achieved positive MCID on the Quality of Life in Epilepsy (QOLIE)-89, as compared to 11.0% of those in the medical group (p < 0.001). On the QOLIE-31, 62.0% of the surgical group and 17.0% of the medical group achieved positive MCID (p < 0.001). Substantially more medically treated patients exhibited clinically significant worsening in QOL, as compared with those surgically treated. The respective medical versus surgical proportions with worsening were 36.67% versus 13.8% in QOLIE31, 20% versus 15% in Health Utility Index-III (HUI-III), and 30% versus 19% in Short Form-36 (SF-36) Mental Composite Score (MCS). The number of patients who need to undergo surgery for one additional person to have a meaningful improvement in the QOLIE-31 is two (number needed to treat = 2). The results also favored surgery using the generic HUI-III instrument, but not with the mental of physical function subscales of the SF-36.

Significance: Significantly more patients in the surgical group achieved meaningful improvement in epilepsy-specific measures of QOL at 6 and 12 months compared to those in the medical group. Substantially more patients in the medical therapy group exhibited clinically significant worsening in their QOL assessed with epilepsy-specific and generic instruments. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.

Keywords: Clinically important difference; Epilepsy surgery; Quality of life; Randomized controlled trial.