The risk for developing vision-threatening retinopathy after cataract surgery in diabetic patients depends on the postoperative follow-up time

Individualised screening for diabetic retinopathy with proliferative retinopathy and macular oedema as separate end points

PURPOSE

A number of algorithms have been developed to calculate screening intervals for diabetic retinopathy on the basis of individual risk factors. However, these approaches have not considered proliferative diabetic retinopathy (PDR) and diabetic macular oedema (DME) as separate end points and death as competing risk.

METHODS

A multi-state survival model with death as competing risk was used to predict the screening interval for diabetic retinopathy based on information about all 2446 patients from a well-defined population who had started treatment for either PDR or DME during 25 years. The performance of the model was tested on the existing database and at seven screening sites on patients who had not developed a treatment requiring condition.

RESULTS

Testing on the existing database showed that at a risk level of 2% the algorithm could predict a screening interval with a success rate higher than 90% and a 1.75 times average prolongation of the screening interval without failing to detect the development of verified PDR og DME. The model was limited to a diabetes duration shorter than 40 years and depended on knowledge of relevant risk factors. At the other participating screening sites the algorithm predicted shorter intervals than the screener.

CONCLUSIONS

Algorithms for individualised screening for diabetic retinopathy can prolong screening intervals without losing patients who develop a vision threatening condition. The calculation of screening intervals requires access to relevant risk factors and should be developed on large data sets that reflect the population in which the algorithm should be used.

The risk for developing vision threatening diabetic retinopathy is influenced by heredity to diabetes

Purpose: Clustering of vision threatening diabetic retinopathy within specific families can be the result of similarities in life style but may also be due to a common genetic background. An evaluation of the role of heredity for the development of diabetic retinopathy may help adjusting control intervals in screening programmes to each patient's individual risk profile.Methods: Survival analysis was used to study whether family history of diabetes among men and women with type 1 or type 2 diabetes together with the degree of heredity could be added as risk factors to improve the prediction of the risk for developing proliferative diabetic retinopathy (PDR) and diabetic macular edema (DME). The study was conducted on data from 12,281 patients followed in the Aarhus area, Denmark, from January 1. 2003 to July 1. 2019.Results: The risk for developing PDR was significantly reduced 2-11 years after known onset of diabetes in the presence of female family members with type 1 diabetes, and the risk for developing DME significantly increased 4-24 years after onset of diabetes in the presence of family members with type 2 diabetes of any sex. These hereditary factors were independent of other studied risk factors such as previous cataract surgery, age of onset of diabetes, metabolic regulation and blood pressure.Conclusions: The presence of family members with diabetes affects the risk for developing vision threatening diabetic retinopathy and affects the risk for developing PDR and DME differently. This evidence may help individualizing the control intervals in screening programmes for diabetic retinopathy.