Estimating the impact of changes in HbA1c, body weight and insulin injection regimen on health related quality-of-life: a time trade off study

BACKGROUND There are limited data on the potential short-term benefits associated with reductions in HbA1c levels, and understanding any immediate improvements in health related quality-of-life (HRQoL) through better glycaemic control may help inform diabetes management decisions. This time-trade-off (TTO) study investigated the short-term impact on HRQoL associated with three different aspects of diabetes management; HbA1c change, body weight change, and the complexity of treatment regimen. METHODS The study was designed in three stages: Stage 1) Qualitative telephone interviews with people with type 2 diabetes (T2D) in Denmark who had experienced a decrease in their HbA1c level. Stage 2) A validation survey with people with T2D in Denmark to obtain quantifiable knowledge on the short-term effects of a change in HbA1c levels. Stage 3) TTO survey using health states based on results from stage 2. Respondents were either adults with T2D (Sweden) or from the general public (UK and Denmark) and were separately asked to evaluate seven health states through an internet-based survey. RESULTS Results from 4060 respondents were available for the TTO analysis (UK n = 1777; Denmark n = 1799, Sweden n = 484). 'Well-controlled diabetes' was associated with utilities of 0.85-0.91 and 'not well-controlled diabetes' with utilities of 0.71-0.80 in all countries. Difference in utilities per HbA1c percentage point was smallest in Sweden and largest in Denmark (between 0.025-0.034 per HbA1c percentage point respectively). The treatment management health state associated with the lowest disutility was the once-daily insulin regimen. The disutility associated with per kg of weight change ranged from 0.0041-0.0073. CONCLUSIONS Changes in HbA1c levels, insulin regimen and body weight are all likely to affect HRQoL for patients with T2D. A change in HbA1c is likely to have a short-term impact in addition to the effect on the development of long term diabetes complications. A treatment which has a simple regimen with fewer injections, and/or the need for less planning, and that causes weight loss or less weight gain, compared with other treatments, will have a positive impact on HRQoL.