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. 2017 Nov;60(11):2174-2182.
doi: 10.1007/s00125-017-4386-0. Epub 2017 Aug 24.

Individualised variable-interval risk-based screening for sight-threatening diabetic retinopathy: the Liverpool Risk Calculation Engine

Antonio Eleuteri  1 , Anthony C Fisher  1 , Deborah M Broadbent  2   3 , Marta García-Fiñana  4 , Christopher P Cheyne  4 , Amu Wang  2 , Irene M Stratton  5 , Mark Gabbay  6 , Daniel Seddon  7 , Simon P Harding  8   9 ; Individualised Screening for Diabetic Retinopathy (ISDR) Study Group
Affiliations

Individualised variable-interval risk-based screening for sight-threatening diabetic retinopathy: the Liverpool Risk Calculation Engine

Antonio Eleuteri et al. Diabetologia. 2017 Nov.

Abstract

Aims/hypothesis: Individualised variable-interval risk-based screening offers better targeting and improved cost-effectiveness in screening for diabetic retinopathy. We developed a generalisable risk calculation engine (RCE) to assign personalised intervals linked to local population characteristics, and explored differences in assignment compared with current practice.

Methods: Data from 5 years of photographic screening and primary care for people with diabetes, screen negative at the first of > 1 episode, were combined in a purpose-built near-real-time warehouse. Covariates were selected from a dataset created using mixed qualitative/quantitative methods. Markov modelling predicted progression to screen-positive (referable diabetic retinopathy) against the local cohort history. Retinopathy grade informed baseline risk and multiple imputation dealt with missing data. Acceptable intervals (6, 12, 24 months) and risk threshold (2.5%) were established with patients and professional end users.

Results: Data were from 11,806 people with diabetes (46,525 episodes, 388 screen-positive). Covariates with sufficient predictive value were: duration of known disease, HbA1c, age, systolic BP and total cholesterol. Corrected AUC (95% CIs) were: 6 months 0.88 (0.83, 0.93), 12 months 0.90 (0.87, 0.93) and 24 months 0.91 (0.87, 0.94). Sensitivities/specificities for a 2.5% risk were: 6 months 0.61, 0.93, 12 months 0.67, 0.90 and 24 months 0.82, 0.81. Implementing individualised RCE-based intervals would reduce the proportion of people becoming screen-positive before the allocated screening date by > 50% and the number of episodes by 30%.

Conclusions/interpretation: The Liverpool RCE shows sufficient performance for a local introduction into practice before wider implementation, subject to external validation. This approach offers potential enhancements of screening in improved local applicability, targeting and cost-effectiveness.

Keywords: Diabetic retinopathy; Risk calculation engine; Risk-based screening.

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Conflict of interest statement

Data availability

The Liverpool RCE Development Dataset generated and analysed during this study is not publicly available because of restrictions on data sharing and commercialisation. A fully anonymised dataset is available from the corresponding author on reasonable request.

Duality of interest

The authors declare that there is no duality of interest associated with this manuscript.

Contribution statement

All authors met ICMJE requirements, making (1) substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; (2) drafting the article or revising it critically for important intellectual content; and (3) giving final approval of the version to be published. SPH wrote the drafts of the manuscript; AE wrote the technical sections and prepared the figures. SPH is responsible for the integrity of the work as a whole. AE is guarantor for the model development and analysis.

Figures

Fig. 1
Fig. 1
Transitions between diabetic retinopathy disease states of the continuous-time Markov process in the Liverpool RCE. DR, diabetic retinopathy
See this image and copyright information in PMC

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