Reliability and Validity of the Audit on Diabetes-Dependent Quality of Life (ADDQoL) and EQ-5D in Elderly Slovenian Diabetes Mellitus Type 2 Patients

Abstract

Purpose: This study reports the reliability and validity analyses of the Audit on diabetes-dependent quality of life (ADDQoL) and EQ-5D in elderly Slovenian diabetic patients. Methods: A cross-sectional study of elderly (age ≥ 65 years) non-insulin dependent diabetes mellitus type 2 (DMT2) patients was carried out. The ADDQoL and EQ-5D surveys were conducted between January and May, 2012. Statistical analysis was performed using IBM SPSS Statistics software, version 20.0. Results: After exclusion of non-eligible respondents, the final sample for the analysis was 261 cases (51% male), resulting in 52.2%of response rate. The mean age of the patients was 70.3 years (SD ± 4.1). The Cronbach’s alpha was 0.93 for ADDQoL and 0.73 for EQ-5D.There was no improvement in the alpha value if any item was deleted in all instruments. Missing value items ranged from 0.8% to 1.5% for EQ-5D, and from 0.8% to 59.1% (working life) in ADDQoL. Spearman’s correlation between the EQ-5D VAS score and ADDQoL weighted overall score resulted in weak correlations coefficient (r = 0.294; p < 0.001). Conclusions: The ADDQoL proved reliable and valid for assessing Health Related Quality of Life (HRQoL) among elderly Slovenian DMT2 patients. EQ-5D seemed to be too generic to describe limitations of DMT2 patients in detail. Using disease specific QoL instruments to learn about patient limitations was recommended. Comparison of ADDQoL results between various studies provided significant differences in the impact of diabetes.