The Minneapolis-Manchester Quality of Life Instrument: Reliability and validity of the adolescent form

Purpose: With improvement in survival after childhood cancer, increasing emphasis is being placed on the impact of treatment and its sequelae on the health-related quality of life (HRQL) of survivors. The Minneapolis-Manchester Quality of Life Instrument (MMQL) is a standardized patient self-report instrument designed to assess HRQL in survivors of childhood cancer. The MMQL is being developed for three age groups to address the changing developmental need of different ages: MMQL-Youth (8 to 12 years), MMQL-Adolescent (13 to 20 years), and MMQL-Young Adult (21 to 45 years). This report focuses on the development and testing of the MMQL-Adolescent Form. Patients and Methods: To validate the instrument, the MMQL-Adolescent Form was administered to 397 adolescents (129 healthy individuals, 110 patients with cancer undergoing therapy, and 158 subjects off therapy for cancer). Factor analysis was conducted to refine the instrument. Construct validity was conducted by comparing similar constructs in the MMQL-Adolescent Form and the Child Health Questionnaire (CHQ). Discriminate validity was determined by comparing healthy children with children with cancer either on or off therapy. Stability of the MMQL was tested by readministering the MMQL-Adolescent Form 2 weeks later. Results: Internal consistency reliability was in the acceptable range for this instrument. The MMQL was able to discriminate between the three study populations. There were high correlations between the MMQL scales and similar CHQ domains. Test-retest reliability of the MMQL-Adolescent Form demonstrated that the instrument was extremely stable in all scales tested. Conclusion: Overall, the data provide evidence for the validity and reliability of the MMQL-Adolescent Form as a comprehensive, multidimensional self-report instrument for measuring HRQL among adolescent survivors of childhood cancer.