Fig. 4.

DeepLIFT gradient plots of the input risk factors. The risk factor categories are indicated by different colors, blue for living habits, grey for demographic information of the subjects, orange for radiographic information, pink for mechanical factors, green for metabolic syndromes and brown for symptomatic information. (a) Demonstrates the gradient of each risk factor in the KOA onset prediction and (b) displays gradients in the prediction of KOA deterioration. Positive gradient would indicate that as the value of the feature increases, the prediction of positive class (i.e. progressors) is favored. Contrariwise, a negative gradient implies increasing the feature value would result in a higher tendency of prediction towards the negative class (i.e. non-progressors). Meanwhile, the magnitude of the gradient correlates to the extent of influence and contribution in the model’s prediction.