پیش بینی زمان تجارت کردن ارزیابی سلامت نوجوانان در چهار کشور آرام با استفاده از ارزیابی کیفیت زندگی (AQoL-6D) ابزار

Objectives Pacific Obesity Prevention in Communities (OPIC) is a community-based intervention project targeting adolescent obesity in Australia, New Zealand, Fiji, and Tonga. The Assessment of Quality of Life Mark 2 (AQoL-6D) instrument was completed by 15,481 adolescents to obtain a description of the quality of life associated with adolescent overweight and obesity, and a corresponding utility score for use in a cost–utility analysis of the interventions. This article describes the recalibration of this utility instrument for adolescents in each country. Methods The recalibration was based on country-specific time trade-off (TTO) data for 30 multiattribute health states constructed from the AQoL-6D descriptive system. Senior secondary students, in a classroom setting, responded to 10 health state scenarios each. These TTO interviews were conducted for 24 groups, comprising 279 students in the four countries resulting in 2790 completed TTO scores. The TTO scores were econometrically transformed by regressing the TTO scores upon predicted scores from the AQoL-6D to produce country-specific algorithms. The latter incorporated country-specific “corrections” to the Australian adult utility weights in the original AQoL. Results This article reports two methodological elements not previously reported. The first is the econometric modification of an extant multi-attribute utility instrument to accommodate cultural and other group-specific differences in preferences. The second is the use of the TTO technique with adolescents in a classroom group setting. Significant differences in utility scores were found between the four countries. Conclusion Statistical results indicate that the AQoL-6D can be validly used in the economic evaluation of both the OPIC interventions and other adolescent programs.

The Pacific Obesity Prevention in Communities (OPIC) project is a four-country project funded in Fiji and Tonga by the Wellcome Trust, New Zealand by the Health Research Council, and Australia by the National Health and Medical Research Council to expand the capacity of the Pacific region to respond to the obesity crisis. The region is faced with among the highest rates of obesity in the world. Prevalence rates for overweight and obesity are around 75% in Tonga [1] and 80% for the Pacific populations living in New Zealand [2,3]. The impact of obesity as a risk factor for diseases such as heart disease, stroke, diabetes, selected cancers, and osteoarthritis has been well documented. A World Health Report in 2002 [4] estimated that obesity, which was the 10th leading cause of avoidable burden, would be the seventh leading cause for 2010 and 2020. The limited capacity of the Pacific Region to respond to the obesity epidemic and the poor evidence base of what works in terms of obesity prevention were the key factors underpinning the project [5]. The OPIC project set out to address these two issues through the development of comprehensive, communitybased intervention programs which targeted adolescents (aged 12–18 years) in each of the four countries. A quasi-experimental design was employed with an intervention period of 3 years and a cohort follow-up, and changes in body mass index as the primary outcome variable. The linked economic studies included the administration of a health-related quality-of-life (QoL) measure to both facilitate description of the QoL burden of adolescent overweight and obesity, and as an outcome measure in a cost–utility analysis (CUA) of the interventions. The latter will enable a comparison of the efficiency of the obesity interventions implemented against a broader spectrum of health-care interventions.

The literature suggests that different MA instruments produce very different results [11]. This does not indicate that CUA is an inappropriate methodology for evaluating programs. The alternative is to ignore QoL or use subjective judgments. While comparison between these options has not been reported in the literature, it is generally true that systematic approaches to problem solving outperform ad hockery. Depending upon study objectives, differences between instruments need not indicate invalidity in the measurement of QoL if the same instrument is used consistently. Invalidity will occur only if the evaluation compares the benefits of QoL with the benefits of life extension with an instrument where this implied “exchange rate” has not been validated. CUA is evolving, and the present study employed new methods. To the authors’ knowledge, this is the first time that TTO exercises have been completed by adolescents and in a classroom setting. A study by Essink-Bot et al. [27] suggested that a group setting could produce acceptable results for much less cost than face-to-face individual interviews. The classroom format was considered appropriate for the OPIC project, as adolescents are accustomed to being in classes, receiving instructions as a group, before completing work on an individual basis. A conscious decision was made not to invite junior secondary students (12–14 years) in the OPIC target group given the cognitive complexity of the task. Qualitative and quantitative results suggest that the process was highly successful. Estimation of utilities using a three-stage procedure is also unique to the AQoL instruments with the econometric correction only used, to date, in AQoL-6D and AQoL-8D (by mid-2010). This latter innovation is particularly important in view of the gross differences between scores obtained with different instruments. It ensures that estimated utilities must be within the range of values obtained independently using the holistic (quasi-gold standard) methodology. The utility weights in the AQoL-6D algorithm have been revised separately for adolescents in each of the four countries (Table 6). The AQoL6D can now be validly used in the economic evaluation of the OPIC interventions, and also in the field for the evaluation of any other adolescent programs in Australia, New Zealand, Fiji, and Tonga. We acknowledge the contribution made by the students in the four countries who gave their time to participate in the TTO exercises. We also express thanks to the schools, principals, and teachers who facilitated this process, and to parents who gave permission for their children to participate. Thanks are also extended to OPIC team members in each country who sought the cooperation of the schools in the process, and made logistical arrangements. Source of financial support: National Health and Medical Research Council (Australia), Health Research Council (New Zealand), Wellcome Trust (Fiji and Tonga).