Mapping AcroQoL scores to EQ-5D to obtain utility values for patients with acromegaly. (3rd April 2018)

• Record Type: Journal Article
• Authors: Badia, Xavier; Trainer, Peter; Biermasz, Nienke R.; Tiemensma, Jitske; Carreño, Agata; Roset, Montse; Forsythe, Anna; Webb, Susan M.
• Is Part Of: Journal of medical economics. Volume 21:Number 4(2018)
• Page Start: 382
• Page End: 389
• Publication Date: 2018-04-03
• Subjects: Acromegaly -- Utilities -- Mapping -- AcroQoL; Medical care -- Cost control -- Periodicals; Medical economics -- Periodicals; 362.10941
• DOI: 10.1080/13696998.2017.1419960
• Languages: English
• ISSNs: 1369-6998

Abstract

Abstract: Aims: To estimate a preference-based single index for the disease-specific instrument (AcroQoL) by mapping it onto the EQ-5D to assist in future economic evaluations. Materials and methods: A sample of 245 acromegaly patients with AcroQoL and EQ-5D scores was obtained from three previously published European studies. The sample was split into two: one sub-sample to construct the model (algorithm construction sample, n = 184), and the other one to confirm it (validation sample, n = 61). Various multiple regression models including two-part model, tobit model, and generalized additive models were tested and/or evaluated for predictive ability, consistency of estimated coefficients, normality of prediction errors, and simplicity. Results: Across these studies, mean age was 50–60 years and the proportion of males was 36–59%. At overall level the percentage of patients with controlled disease was 37.4%. Mean (SD) scores for AcroQoL Global Score and EQ-5D utility were 62.3 (18.5) and 0.71 (0.28), respectively. The best model for predicting EQ-5D was a generalized regression model that included the Physical Dimension summary score and categories from questions 9 and 14 as independent variables (Adj. R 2 = 0.56, with mean absolute error of 0.0128 in the confirmatory sample). Observed and predicted utilities were strongly correlated (Spearman r = 0.73, p < .001) and paired t -Student test revealed non-significant differences between means ( p > .05). Estimated utility scores showed a minimum error of ≤10% in 45% of patients; however, error increased in patients with an observed utility score under 0.2. The model's predictive ability was confirmed in the validation cohort. Limitations and conclusions: A mapping algorithm was developed for mapping of AcroQoL to EQ-5D, using patient level data from three previously published studies, and including validation in the confirmatory sub-sample. Mean (SD) utilities index in this study population was estimated as 0.71 (0.28). Additional research may be needed to test this mapping algorithm in other acromegaly populations.