Estimating the minimally important difference (MID) of the Diabetes Health Profile-18 (DHP-18) for Type 1 and Type 2 Diabetes Mellitus

Aims: The DHP-18 is a widely used measure of health related quality of life in diabetes mellitus but it is unclear what constitutes a meaningful change in score on each domain. The aim of this study was to establish estimates for the minimally important difference (MID) for each of the domains.

Methods: The MID for each domain was estimated using both anchor and distribution based approaches which were applied to data from both the United Kingdom and France. A range of anchors were tested.

Results: A global health change anchor was found to be more acceptable for Type 1 diabetes than for Type 2. MID estimates varied by domain, by estimation approach used, and by diabetes type. For Type 1 diabetes the Psychological Distress domain estimates ranged from 2.86 to 11.05, Barriers to Activity domain from 2.87 to 11.32 and Disinhibited Eating domain from 1.03 to 11.53. For Type 2 diabetes the Psychological Distress estimates ranged from 0.94 to 9.71; Barriers to Activity from 1.66 to 9.88 and Disinhibited Eating from 0.90 to 11.64.

Conclusions: This is the first attempt to derive estimates for the MID of an English language measure of health related quality of life in diabetes. For Type 1 diabetes we recommend using the mean MID value using both approaches. For Type 2 we recommend applying more weight to the distribution based estimations. The MID values identified in this study will help clinicians and researchers using the DHP-18 to identify clinically meaningful change in patient reported outcomes.