Validity of three measures of health-related quality of life in children with intractable epilepsy

PURPOSE: Validity studies on health-related quality of life (HRQOL) scales for pediatric epilepsy are few, and cross-validation with other samples has not been reported. This study was designed to assess the validity of three parent-rated measures of HRQOL in pediatric epilepsy: (a) the Impact of Childhood Illness Scale (ICI), (b) the Impact of Child Neurologic Handicap Scale (ICNH), and (c) the Hague Restrictions in Epilepsy Scale (HARCES). METHODS: Retrospective data were examined for 44 children with intractable epilepsy. Validity was assessed by evaluating differences across epilepsy severity groups as well as correlations between HRQOL scales and neurologic variables (seizure severity, epilepsy duration, current/prior antiepileptic medications) and psychosocial measures (emotional functioning, IQ, social skills, adaptive behavior). Scale overlap with a global QOL rating also was assessed. RESULTS: The HRQOL measures were moderately to highly intercorrelated. The scales differed in terms of their associations with criterion measures. The HARCES was related to the highest number of neurologic variables and the ICNH to the fewest. All three scales were related to psychosocial functioning and to global quality of life. CONCLUSIONS: The results of this study suggest that the three measures are likely adequate measures of HRQOL for use in intractable childhood epilepsy. The measures were highly intercorrelated, and they were all broadly related to criterion measures reflecting specific domains of HRQOL as well as global QOL. Some differences between scales emerged, however, that suggest care in choosing HRQOL instruments for children with epilepsy.     

The health-related quality of life of children with refractory epilepsy: a comparison of those with and without intellectual disability

PURPOSE: To determine whether refractory epilepsy affects the health-related quality of life (HRQOL) of children with or without intellectual disability (ID), and if the presence of ID independently compromises HRQOL in children with refractory epilepsy. METHODS: Subjects were parents of children with refractory epilepsy, whose syndrome had been defined using ILAE (International League Against Epilepsy) criteria and video-EEG monitoring. Children had the presence or absence of ID determined by formal neuropsychological or educational assessment. The relative effect of epilepsy on the two intellectual ability groups was determined using relevant clinical variables. Parents completed a valid epilepsy-specific HRQOL questionnaire for children, the Quality of Life in Childhood Epilepsy Questionnaire (QOLCE), and, depending on intellectual ability level, the Child Behaviour Checklist or Developmental Behaviour Checklist. RESULTS: Both intellectually normal children with epilepsy and children with epilepsy and ID were more likely to have psychosocial problems compared with their respective intellectual ability reference populations. The results also revealed that children with ID had reduced HRQOL compared with intellectually normal children; a result independent of epilepsy. Analysis of the relationship between epilepsy variables and HRQOL revealed that the QOLCE was the most sensitive in detecting variation in age at onset, seizure frequency, and medications taken. CONCLUSIONS: The HRQOL of children with refractory epilepsy is greatly affected, regardless of intellectual ability level. The presence of ID in children with epilepsy independently depresses HRQOL outcomes. Compared with two generic HRQOL measures, the QOLCE was the most sensitive measure to variation in epilepsy variables.     

Development of the Quality of Life in Epilepsy Inventory

Summary: We developed an instrument to measure health-related quality of life (HRQOL) in epilepsy. A 99-item inventory was constructed from the RAND 36-Item Health Survey (generic core), with 9 additional generic items, 48 epilepsy-targeted items, and 6 other items concerning attitudes toward epilepsy and self-esteem. We administered the 99-item inventory to 304 adults with epilepsy at 25 epilepsy centers. Patients and patient-designated proxies completed the inventory and were retested 1–91 days later. A multitrait scaling analysis of these data led to retention of 86 items distributed in 17 multiitem scales (Cronbach's alpha ranged from 0.78 to 0.92). Factor analysis of the 17 multiitem scales yielded four underlying dimensions of health: an epilepsy-targeted dimension, a cognitive factor, mental health, and physical health. Construct validity was supported by significant patient-proxy correlations for all scales and correlations between neuropsychologic tests and self-reported emotional and cognitive function (all p values < 0.05). There were significant negative correlations between the four factor scores derived from the HRQOL scales and neurotoxicity, systemic toxicity, and health care utilization (except for the correlation between mental health factor and health care utilization; all p values < 0.05). Patients who were seizure-free in the preceding year reported better HRQOL for the overall score, three of the four factor scores, and 8 of the 17 scale scores than did patients with a high frequency of seizures. Relative validity analysis showed that the epilepsy-targeted factor and three of its four component scales were more sensitive to categorization of patients by severity of seizure frequency and type than scales tapping physical health, mental health, or cognitive function. These cross-sectional data support the reliability and validity of this measure of HRQOL in epilepsy. The addition of an epilepsy-targeted supplement to the generic core improved the sensitivity to severity of epilepsy. The 86 items included in the field testing were supplemented by three additional items to form the Quality of Life in Epilepsy (QOLIE-89) inventory.     

Development of the Quality of Life in Epilepsy Inventory for Adolescents: The QOLIE-AD-48

PURPOSE: We report the development of an instrument to assess health-related quality of life (HRQOL) in adolescents with epilepsy. METHODS: A sample of 197 English-speaking adolescents (aged 11-17 years) with epilepsy completed a test questionnaire of 88 items. Also included were mastery and self-esteem scales to assess external validity. A parent simultaneously completed an 11-item questionnaire to evaluate the child's HRQOL. Both adolescent and parent questionnaires were repeated in 2-4 weeks. Demographic information and information pertaining to seizures were collected at baseline along with assessment of systemic and neurologic toxicity. RESULTS: The QOLIE-AD-48 contains 48 items in eight subscales: epilepsy impact (12 items), memory/concentration (10), attitudes toward epilepsy (four), physical functioning (five), stigma (six), social support (four), school behavior (four), health perceptions (three), and a total summary score, with higher scores indicating better HRQOL. Internal construct validity was demonstrated in a single-factor solution for the eight dimensions. All correlations were statistically significant at p < 0.05 level. Internal consistency reliability estimated by Cronbach's alpha coefficient was 0.74 for the summary score and ranged from a low of 0.52 (three-item Health Perceptions Scale) to 0.73-0.94 for the other individual scales. Good test-retest reliability was found for the overall measure (0.83). Summary score correlations with the two external validity scales, self-efficacy and self-esteem were 0.65 and 0.54, respectively. Statistically significant differences in summary scores indicating that HRQOL was increasingly better for adolescents as seizure severity decreases (no seizures = 77+/-13, low = 70+/-17, high = 63+/-17) were found among seizure-severity groups. CONCLUSIONS: These data describe the development of a robust instrument to evaluate HRQOL in adolescents with epilepsy. Empiric analyses provide strong evidence that the QOLIE-AD-48 is both a reliable and valid measure for adolescents with epilepsy.     

Changes in Quality of Life in Epilepsy: How Large Must They Be to Be Real?

PURPOSE: The study goal was to assess the magnitude of change in generic and epilepsy-specific health-related quality-of-life (HRQOL) instruments needed to exclude chance or error at various levels of certainty in patients with medically refractory epilepsy. METHODS: Forty patients with temporal lobe epilepsy and clearly defined criteria of clinical stability received HRQOL measurements twice, 3 months apart, using the Quality of Life in Epilepsy Inventory-89 and -31 (QOLIE-89 and QOLIE-31), Liverpool Impact of Epilepsy, adverse drug events, seizure severity scales, and the Generic Health Utilities Index (HUI-III). Standard error of measurement and test-retest reliability were obtained for all scales and for QOLIE-89 subscales. Using the Reliable Change Index described by Jacobson and Truax, we assessed the magnitude of change required by HRQOL instruments to be 90 and 95% certain that real change has occurred, as opposed to change due to chance or measurement error. RESULTS: Clinical features, point estimates and distribution of HRQOL measures, and test-retest reliability (all > 0.70) were similar to those previously reported. Score changes of +/-13 points in QOLIE-89, +/-15 in QOLIE-31, +/-6.3 in Liverpool seizure severity-ictal, +/-11 in Liverpool adverse drug events, +/-0.25 in HUI-III, and +/-9.5 in impact of epilepsy exclude chance or measurement error with 90% certainty. These correspond, respectively, to 13, 15, 17, 18, 25, and 32% of the potential range of change of each instrument. CONCLUSIONS: Threshold values for real change varied considerably among HRQOL tools but were relatively small for QOLIE-89, QOLIE-31, Liverpool Seizure Severity, and adverse drug events. In some instruments, even relatively large changes cannot rule out chance or measurement error. The relation between the Reliable Change Index and other measures of change and its distinction from measures of minimum clinically important change are discussed.     

Seizure recency and quality of life in adolescents with childhood-onset epilepsy

Health-related quality of life (HRQOL) is associated with seizure recency among adults with epilepsy. In a prospective, community-based study of long-term outcomes of childhood-onset epilepsy, we evaluated whether worse HRQOL is associated with more recent seizures among children and adolescents with epilepsy. We used the Child Health Questionnaire (CHQ), a generic measure with child and parent-proxy versions, to measure HRQOL. Among 277 children with epilepsy (CWE) assessed 9 years after diagnosis, parent-proxy reported but not child self-reported HRQOL was significantly worse for those having seizures in the prior year than for those who were seizure free ≥1 year across the majority of scales. There were no differences between CWE in remission for 1-5 years and those seizure free ≥5 years for child and parent-proxy reported HRQOL with the exception of the parent Emotional Impact scale, suggesting that HRQOL differences related to seizure recency level off after the initial year of remission.     

Procedure for Developing a Quality-of-Life Measure for Epilepsy Surgery Patients

Summary: In 1990, the NIH Consensus Conference Panel on epilepsy surgery called for the development and use of reliable and valid health-related quality-of-life (HRQOL) measures in epilepsy surgery studies. A HRQOL measure for epilepsy surgery patients has been developed and evaluated. The procedure, which could also be used to develop HRQOL measures for other neurological diseases, entails the following steps: (a) specify desired characteristics of the measure; (b) identify relevant HRQOL areas by reviewing the literature; (c) assemble generic core items and disease-specific supplementary items; (d) pilot test and revise the measure; (e) administer revised measure items to a large sample of epilepsy surgery patients; (f) perform item analysis to evaluate hypothesized item placement within scales; and (g) assess the reliability and validity of the scales. The product of this process, the Epilepsy Surgery Inventory (ESI)-55, is a self-report measure of 11 dimensions of HRQOL. It is brief, comprehensive, and reliable; preliminary evidence supports its validity.     

Comorbidities and predictors of health-related quality of life in Dravet syndrome

Purpose: Health‐related quality of life (HRQOL) has emerged as a widely accepted measure to evaluate how chronic disease impacts on an individual’s physical, social, and mental well‐being. There is a paucity of data focusing on HRQOL in specific epilepsy syndromes and their associated needs. In this study our aim was to describe the comorbidities and disease‐related predictors for HRQOL in Dravet syndrome, an epileptic encephalopathy, with defined genetic etiology. We anticipate that this will help us to better recognize and understand the needs of children and families and aid treatment planning in this severe epilepsy syndrome. Methods: One hundred sixty‐three individuals with Dravet syndrome and their families participated in the study. Detailed clinical and demographic information was available for each case. HRQOL was evaluated with two epilepsy‐specific instruments, the Impact of Pediatric Epilepsy Scale (IPES) and the Epilepsy & Learning Disabilities Quality of Life Questionnaire (ELDQOL); a generic HRQOL instrument; the Pediatric Quality of Life Inventory (PedsQL); and a behavioral screening tool, the Strength and Difficulties Questionnaire (SDQ). Key Findings: HRQOL was significantly lower for children with Dravet syndrome compared to normative data (p < 0.001). A cross‐sectional evaluation of measures across different age groups revealed that PedsQL generic core and cognitive function scales decreased in older age categories, indicating worse HRQOL (p < 0.001). Assessment of epilepsy severity demonstrated that symptoms were rated very severe in 10 (6%) of 162 cases, somewhat severe in 78 (48%) of 162, moderate in 51 (32%) of 162, and mild in 23 (14%) of 162 cases. The epilepsy severity correlated significantly with the IPES total impact score (r = 0.466, p < 0.001, n = 162). The IPES total impact scores in the Dravet group (n = 162) were significantly higher than scores measured in the original validation sample of epileptic children with and without learning difficulties (± SD) (21.0 ± 8.7 vs. 11.6 ± 5.4, t = 8.95, p < 0.001, n = 46). On the SDQ, 35% of children scored in the abnormal range for “conduct problems,” 66% for “hyperactivity/ inattention,” and 76% for “peer relationships.” Regression analysis revealed that young age at seizure onset (p = 0.019), presence of myoclonic seizures (p = 0.029), motor disorder (p = 0.048), learning difficulties (p = 0.002), epilepsy severity (p < 0.001), and behavioral difficulties (p < 0.001) each independently predicted poorer HRQOL. Behavioral problems such as hyperactivity/inattention were the strongest predictors of poorer HRQOL. Significance: This is the first comprehensive study of HRQOL in an etiologically well‐defined epilepsy syndrome. HRQOL in Dravet syndrome depends on a series of independent factors including seizure control, behavior, cognitive, and motor problems. Identification of specific comorbidities in Dravet syndrome will facilitate a distinct and multidisciplinary approach to management, addressing seizure control, behavior problems, cognitive difficulties, and motor impairment.     

Health-related quality of life in epilepsy: findings obtained with a new Italian instrument

The aim of the present study was to evaluate the Epi-QoL, a new Italian-specific measure of health-related quality of life (HRQOL) for adults with epilepsy; the clinical variables that affected the HRQOL score were also assessed. The Epi-QoL is a 46-item self-administered questionnaire focusing on six domains: Physical Functioning, Cognitive Functioning, Emotional Well-Being, Social Functioning, Seizure Worry, and Medication Effects. Eight hundred fifteen patients recruited from 24 secondary and tertiary Italian centers for the care of epilepsy were assessed. The results supported the reliability and validity of the Epi-QoL as a measure of HRQOL. The variables that significantly affected HRQOL scores were: geographic area, gender, seizure frequency, prognostic categories, number of medications, comorbidity, presence of cognitive impairment, psychiatric disturbances, and disability. We believe that a new specific questionnaire for the evaluation of HRQOL in Italy can contribute much to the understanding of the influence of epilepsy on patients' lives.     

Development and Cross-Cultural Translations of a 31-Item Quality of Life in Epilepsy Inventory

Summary: Purpose: We report the development of a questionnaire to assess health-related quality of-life (HRQOL) in people with epilepsy and the process of cross-cultural translations of the questionnaire.
Methods: A sample of 304 adults with epilepsy from 25 seizure clinics in the United States was used to derive an abbreviated questionnaire focusing on epilepsy-related issues from a longer, 89-item instrument (QOLIE-89). A rigorous forward-backward-forward system was used for cross-cultural translation.
Results: A 31-item questionnaire (QOLIE-31, version 1.0) resulted, comprising seven subscales covering genral and epilepsy-specific domains. Subscale and total scores can be calculated. The subscales were grouped into two factors: Emotional/Psychological Effects (seizure worry, overall QOL, emotional well-being, energy/fatigue subscales) and Medical/Social Effects (medication effects, work-driving-social limits, cognitive function subscales). Cross-cultural translations were made from U.S.-English into Danish, Dutch, German, Canadian French, French, Italian, Spanish, Swedish, and U.K. English Versions 1.1.
Conclusions: Our results support the reliability and validity of the QOLIE-31 (U.S.-English version 1.0) as a measure of HRQOLIE. Cross-cultural translations into nine other languages make it feasible to use the QOLIE-31 (version 1.1) in multinational clinical trials after validation in each population or concurrent with clinical trial.