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

Liverpool Risk Calculation Engine
Markov modelling predicted progression to screen-positive (referable diabetic retinopathy) against the local cohort history. 
Markov modelling
Covariates were selected from a dataset created using mixed qualitative/quantitative methods. 
mixed qualitative/quantitative methods
Retinopathy grade informed baseline risk and multiple imputation dealt with missing data. 
multiple imputation
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. 
near-real-time warehouse