Methods for measuring outcomes to evaluate interventions to improve health-related quality of life in HIV infection

Abstract

This paper describes strategies for measuring outcomes to evaluate interventions to improve health-related quality of life (HRQL) in HIV infection and presents data comparing different methods of measuring HRQL from an ongoing randomized, controlled trial. Conceptual and methodological contributions from the literature on the assessment of health status and quality of life are reviewed, followed by a summary of empirical work on measurement of HRQL in HIV infection and description of the outcome measurement strategy adopted in this study.

Preliminary data from the baseline phase of a randomized, controlled trial of an intervention to improve quality of life in 81 persons with HIV infection are analyzed to address issues related to the measurement of outcomes. Three types of measures were used including: i) outcome measures of quality of life (SF-36, QL-Index. HIVIS. patient utilities), psychological well-being (POMS, CES-D, Impact of Event Scale), clinical status (symptoms, T4 cell counts, perceived health status), and costs associated with hospital care; ii) measures of social support (ISEL, satisfaction with support, difficulty seeking support); and iii) measures of personality characteristics hypothesized to be related to outcome (self-esteem, mastery). Correlational analyses were used to examine issues related to generic vs. disease-specific measures and the reliability and construct validity of different outcome measures. Findings are discussed in terms of the reliability and convergent validity of different outcome measures; construct validity of HRQL measures compared to psychological vs. clinical outcomes; and construct validity of HRQL measures compared to social support and personality measures.

Key Words:

• HIV/AIDS
• quality of life
• health status assessment
• outcomes assessment/ measurement
• construct validity
• behavioural interventions.