Establishing the minimum clinically important difference of the Quality of Life in Childhood Epilepsy Questionnaire.

Objective: To estimate the minimum clinically important difference (MCID) for the parent-reported 55-item Quality of Life in Childhood Epilepsy Questionnaire (QOLCE-55) and its shortened 16-item version, QOLCE-16.

Methods: Data came from 74 children with epilepsy (CWE) (ages 4-10, mean age = 8 [SD = 1.8]) enrolled in the Making Mindfulness Matter in Epilepsy (M3-E) trial, a pilot, parallel randomized-controlled trial of a mindfulness-based intervention. Both anchor-based and distribution-based methods were used to estimate MCID values for the QOLCE-55 and QOLCE-16. For the anchor-based approach, the Patient Centered Global Ratings of Change (PCGRC) scale and linear regression analysis were used to estimate the MCID. For the distribution-based approach, .5 SD of the health-related quality of life (HRQOL) change score distribution was used to estimate the MCID.

Results: For the QOLCE-55, the MCID obtained using an anchor-based approach was 10 points and using a distribution-based method was 6 points. For the QOLCE-16, the MCID obtained using an anchor-based method was 13 points and using a distribution-based method was 7 points.

Significance: This is the first study to estimate MCID values for the QOLCE-55 and the QOLCE-16. It has been well documented that CWE are at risk of experiencing psychological, behavioral, and cognitive impairments, which can negatively impact their HRQOL. Reporting MCID values for the QOLCE-55 and QOLCE-16 is important in determining whether changes in HRQOL observed are meaningful to CWE themselves, as a key factor in shaping the nature of epilepsy care delivered.