Estimation of minimally important difference of the EQ-5D-5L utility scores among patients with either hypertension or diabetes or both: a cross-sectional study in Hong Kong.

Abstract

To estimate and report the minimally important difference (MID) of the EuroQol five-dimensional five-level questionnaire (EQ-5D-5L) using the Hong Kong (HK) utility score among patients with either hypertension or diabetes or both. Data were analysed using secondary data analysis based on a cross-sectional study assessing patients' experiences in HK. A representative sample was recruited from 26 specialist outpatient clinics in HK. We analysed data from 2231 and 662 patients who reported having hypertension or diabetes alone, respectively, and 874 patients had these two diseases. An instrument-defined approach was applied to estimate MID stratified according to sex and age for the three subpopulations. The overall MID (oMID) estimates were 0.089, 0.086 and 0.089 for patients with hypertension or diabetes alone and with these two diseases, respectively. The adjusted MID (aMID) estimate was smaller than the oMID, and the improved MID was larger than the deteriorated MID. Women had larger oMID but smaller aMID than men. Younger respondents had larger aMID than older respondents. Effect sizes ranged from 0.30 to 0.503, which fit our preset criteria. Four types of MID of the EQ-5D utility score for patients with hypertension or diabetes alone and with these two diseases were reported. Variations in the MID estimates should be further explored in other populations or using different statistical methods.