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.

Canagliflozin, dapagliflozin and empagliflozin monotherapy for treating type 2 diabetes: systematic review and economic evaluation

“…The costs associated with events have already been updated, the UKPDS84 195 being an update of the UKPDS65. 196 The QoL estimates have also been updated in Alva et al 197 But the format of the analysis of Alva et al 197 is less closely aligned with the events of the UKPDS84 195 when compared with the alignment of the QoL estimates of the UKPDS62 198 with the events of the UKPDS68. 193 …”

“…The QoL at baseline and the QoL decrements associated with the complications of diabetes were drawn from the recent paper by Alva et al, 197 which reanalysed the updated UKPDS data set and in some sense updated the values of the UKPDS62, 198 which is the paper that the AG modelling relies upon. The values and a commentary upon this are presented later in the comparison of modelling inputs used by the companies and the AG.…”

“…But this is a respected publication, and, as Janssen is using the ECHO-T2DM model, the health states of their model are not so obviously aligned with the health states of the UKPDS OM1 and UKPDS OM2 for which UKPDS 197 which is an analysis of the updated UKPDS data set with Alva et al 197 expressing a clear preference for the fixed-effects estimates over their ordinary least squares (OLS) estimates. This explicitly analyses the data longitudinally in order to estimate the QoL pre and post and event and the impact of events upon an individual, rather than comparing patients cross-sectionally.…”

“…This has obvious attractions, but there may be some difficulty when applying these estimates in that the coefficients for blindness and a history of MI are positive. Within Alva et al, 197 these coefficients and that for IHD are not statistically significant, so it could be argued that these could or should be set to zero. But if these are set to zero, it would obviously be preferable for the coefficients to have been further explored or excluded within the analysis of Alva et al,197 in order to explore the impact that this would have upon the estimates of the other coefficients.…”

“…But if these are set to zero, it would obviously be preferable for the coefficients to have been further explored or excluded within the analysis of Alva et al,197 in order to explore the impact that this would have upon the estimates of the other coefficients. But, given its choice of Alva et al 197 as the source of its QoL estimates, this option was not available to Boehringer Ingelheim.…”