Estimating the utility value of hypoglycaemia according to severity and frequency using the visual analogue scale (VAS) and time trade-off (TTO) survey

Objectives: The primary objective of this study was to estimate the health utility values for hypoglycaemia events according to their severity and frequency. The secondary objective was to compare the health utilities between those with Type 2 Diabetes Mellitus and the general population.

Method: The health utilities of hypoglycaemia event were measured using Visual Analogue Scale (VAS) and Time Trade-Off (TTO) methods among conveniently sampled consenting adults (>18 years and literate in either English or Malay language), which were then divided into two groups: those in the general population (GP) and those with Type 2 Diabetes Mellitus (T2DM). Each respondent was required to value 13 different health states, including frequencies of daytime hypoglycaemia and nocturnal hypoglycaemia, each depending on its severity (non-severe or severe).

Results: 256 respondents from the GP and 99 respondents with T2DM completed the survey. The T2DM group gave higher VAS-values compared to the GP group. The highest mean VAS-utility value for non-severe nocturnal hypoglycaemia occurring once monthly was 0.543 (SD 0.161), and for severe daytime hypoglycaemia occurring once quarterly was 0.293 (SD 0.162) which was the lowest utility value compared to other health states. However, non-severe nocturnal hypoglycaemia occurring once quarterly was 0.537 (SD 0.284) and has the highest TTO-utility value. Severe nocturnal hypoglycaemia occurring once quarterly has the lowest utility value which was -0.104 (SD 0.380). Daytime hypoglycaemia has lower utility value compared to nocturnal hypoglycaemia. Severe hypoglycaemia has a greater disutility compared with the non-severe hypoglycaemia in both studied groups.

Conclusion: The findings show that as a health utility, hypoglycaemia has a substantial impact on utility with severe hypoglycaemia having a greater negative impact compared to non-severe events across the board. This highlights the importance of preventing development of severe hypoglycaemia in patients with Type 2 Diabetes Mellitus at any time of the day.