Diminishing marginal disutility of hypoglycaemic events: results from a time trade-off survey in five countries.
BACKGROUND
The negative impact of hypoglycaemic events on health-related quality of life (HRQoL) may be evaluated by attaching published disutilities to these events. It is suggested that the marginal negative impact of individual hypoglycaemic events on HRQoL may decrease as the overall frequency increases.


METHODS
Using disutility values from a large-scale (>8,000 respondents), time trade-off (TTO) study, nonlinear regression curves were fitted to the total disutility of different frequencies of non-severe daytime and nocturnal hypoglycaemic events. Nonparametric bootstrapping was applied to characterise the uncertainty of the marginal disutility.


RESULTS
Power function regression curves were estimated at U d = 0.0141x (0.3393) and U d = 0.0221x (0.3277). An increase from 0 to 1 hypoglycaemic event per year produced a utility decrease of 0.0141 and 0.0221 for non-severe daytime and nocturnal events, respectively. An increase from 25 to 26 events per year produced a marginal impact of 0.0006 and 0.0008 for non-severe daytime and nocturnal events, respectively.


CONCLUSIONS
These data concur with the noted phenomenon of "first being worst" as regards hypoglycaemic events. This finding may reflect a coping mechanism on the part of patients, a maximum limit for trading off remaining lifetime or the nature of the study.


CONCLUSIONS
Applying nonlinear functions to the TTO data might improve the precision of the measured impact of hypoglycaemic events.
Centre of Health Economics Research (COHERE), Campusvej 55, 5230, Odense M, Denmark, jtl@sam.sdu.dk.
Jørgen T
JT
Lauridsen
Jonas
J
Lønborg
Jens
J
Gundgaard
Henrik Holm
HH
Jensen
D000368:Aged; D048909:Diabetes Complications / Q000523:psychology*; D003922:Diabetes Mellitus, Type 1; D003924:Diabetes Mellitus, Type 2; D005260:Female; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D007003:Hypoglycemia / Q000209:etiology / Q000523:psychology*; D007004:Hypoglycemic Agents / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D018709:Statistics, Nonparametric
D007004:Hypoglycemic Agents