Modelling EuroQol health‐related utility values for diabetic complications from CODE‐2 data

Abstract

Recent research has employed different analytical techniques to estimate the impact of the various long-term complications of type 2 diabetes on health-related utility and health status. However, limited patient numbers or lack of variety of patient experience has limited their power to discriminate between separate complications and grades of severity. In this study alternative statistical model forms were compared to investigate the influence of various factors on self-assessed health status and calculated utility scores, including the presence and severity of complications, and type of diabetes therapy. Responses to the EuroQol EQ-5D questionnaire from 4641 patients with type 2 diabetes in 5 European countries were analysed. Simple multiple regression analysis was used to model both visual analogue scale (VAS) scores and time trade-off index scores (TTO). Also, two complex models were developed for TTO analysis using a structure suggested by the EuroQol calculation algorithm. Both VAS and TTO models achieved greater explanatory power than in earlier studies. Relative weightings for individual complications differed between VAS and TTO scales, reflecting the strong influence of loss of mobility and severe pain in the EuroQol algorithm. Insulin-based therapy was uniformly associated with a detrimental effect equivalent to an additional moderate complication. Evidence was found that TTO values are not responsive in cases where 3 or more multiple complications are present, and therefore may underestimate utility loss for patients most adversely affected by complex chronic diseases like diabetes.

Quality of Life in Patients with Type 2 Diabetes in Poland – Comparison with the General Population Using the EQ-5D Questionnaire

“…The average objective HRQoL assessment (EQ-5D index) differed significantly between the populations: from about 0.61 in Greece and 0.67 in the UK, Italy, Canada and Finland, to around 0.80 in the United States and 0.84 in Spain. The largest studies, with probably the most reliable measurements, indicated a level of 0.69 (5 countries in the European Union, n = 4641) to about 0.77 (United Kingdom, n = 3192) and 0.78 (United States, n = 3849) [20][21][22]. These observed differences can be explained by several different factors, e.g.…”

The clinical effectiveness and cost-effectiveness of inhaled insulin in diabetes mellitus: a systematic review and economic evaluation

“…Utility detriments within the modelling are informed by the detriments reported across the studies of Bagust and Beale, 98 Clarke and colleagues 100 and Coffey and colleagues. 97 The principal differences occur in end-stage renal disease, minor transplantation and blindness in one eye (Table 52).…”

“…In addition to these, Bagust and Beale 98 explore a compound effects mode, but as the compound modelling components are not readily applicable to the modelling undertaken within the EAGLE package, these are not considered in the following. The values for the VAS and TTO modelling are summarised in Table 19 98 Clarke and colleagues 100 use EQ-5D data from 3192 British people with type 2 diabetes from the UKPDS 62 survey to model the impact that diabetic complications have on both the VAS of EQ-5D and the TTO social tariff as reported by Dolan. 96 Clarke and colleagues 100 did not modify the TTO values, but did apply Tobit modelling in an attempt to reduce bias that might result from a significant proportion of respondents reporting themselves as being in full health.…”

“…Clarke and colleagues 100 also distinguish between the effect of a complication in the year it is reported and the effect of a complication in subsequent years. As with Bagust and Beale, 98 they also explore some compound effects modelling, but for the same reasons as for Bagust and Beale this is not considered in what follows. The values for the VAS and TTO modelling are summarised in Table 19.…”

“…As the CODE-2 survey is analysed in detail by Bagust and Beale, 98 and the Redekop group is not a British subsample, it has not been considered further.…”