title: The effect of diabetes complications on health-related quality of life: the importance of longitudinal data to address patient heterogeneity.
abstract: We estimate the impact of six diabetes-related complications (myocardial infarction, ischaemic heart disease, stroke, heart failure, amputation and visual acuity) on quality of life, using seven rounds of EQ-5D questionnaires administered between 1997 and 2007 in the UK Prospective Diabetes Study. The use of cross-sectional data to make such estimates is widespread in the literature, being less expensive and easier to collect than repeated-measures data. However, analysis of this dataset suggests that cross-sectional analysis could produce biased estimates of the effect of complications on QoL. Using fixed effects estimators, we show that variation in the quality of life between patients is strongly influenced by time-invariant patient characteristics. Our results highlight the importance of studying quality-of-life changes over time to distinguish between time-invariant determinants of QoL and the effect on QoL of specific events such as diabetes complications.
authors.affiliation: HERC, Department of Public Health, University of Oxford, Oxford, UK.
authors.forename: Maria
authors.initials: M
authors.lastname: Alva
authors.forename: Alastair
authors.initials: A
authors.lastname: Gray
authors.forename: Borislava
authors.initials: B
authors.lastname: Mihaylova
authors.forename: Philip
authors.initials: P
authors.lastname: Clarke
mesh_terms: D000368:Aged; D001766:Blindness / Q000453:epidemiology / Q000209:etiology; D003430:Cross-Sectional Studies; D048909:Diabetes Complications / Q000453:epidemiology*; D058065:Diabetic Cardiomyopathies / Q000453:epidemiology; D003930:Diabetic Retinopathy / Q000453:epidemiology; D006333:Heart Failure / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009203:Myocardial Infarction / Q000453:epidemiology / Q000209:etiology; D017202:Myocardial Ischemia / Q000453:epidemiology / Q000209:etiology; D011446:Prospective Studies; D011788:Quality of Life; D020521:Stroke / Q000453:epidemiology / Q000209:etiology; D011795:Surveys and Questionnaires; D006113:United Kingdom / Q000453:epidemiology
keywords: Quality of life; diabetes-related complications; fixed effects; heterogeneity; selection