Development and validation of a deep learning algorithm based on fundus photographs for estimating the CAIDE dementia risk score

Importance: The Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) dementia risk score is a recognized tool for dementia risk stratification. However, its application is limited due to the requirements for multidimensional information and fasting blood draw. Consequently, effective, convenient and noninvasive tool for screening individuals with high dementia risk in large population-based settings is urgently needed. Objective: To develop and validate a deep learning algorithm using retinal fundus photographs for estimating the CAIDE dementia risk score and identifying individuals with high dementia risk. Design: A deep learning algorithm trained via fundus photographs was developed, validated internally and externally with cross-sectional design. Setting: Population-based. Participants: A health check-up population with 271,864 adults were randomized into a development dataset (95%) and an internal validation dataset (5%). The external validation used data from the Beijing Research on Ageing and Vessel (BRAVE) with 1,512 individuals. Exposures: The estimated CAIDE dementia risk score generated from the algorithm. Main Outcome and Measure: The algorithm performance for identifying individuals with high dementia risk was evaluated by area under the receiver operating curve (AUC) with 95% confidence interval (CI). Results: The study involved 258,305 participants (mean aged 42.1 years, men: 52.7%) in development, 13,559 (mean aged 41.2 years, men: 52.5%) in internal validation, and 1,512 (mean aged 59.8 years, men: 37.1%) in external validation. The adjusted coefficient of determination (R2) between the estimated and actual CAIDE dementia risk score was 0.822 in the internal and 0.300 in the external validations, respectively. The algorithm achieved an AUC of 0.931 (95%CI, 0.922 to 0.939) in the internal validation group and 0.782 (95%CI, 0.749 to 0.815) in the external group. Besides, the estimated CAIDE dementia risk score was significantly associated with both comprehensive cognitive function and specific cognitive domains. Conclusions and Relevance: The present study demonstrated that the deep learning algorithm trained via fundus photographs could well identify individuals with high dementia risk in a population-based setting. Our findings suggest that fundus photography may be utilized as a noninvasive and more expedient method for dementia risk stratification.