Apparent Performance of the Tophi Formation Risk Nomogram
The calibration curve of the nomogram that predicts the risks of tophi formation amongst gout patients was demonstrated as having good agreement with the cohort (Figure 3 ). The C-index was 0.854 (95% CI: 0.772–0.936) for the cohort, and was confirmed to be 0.810 when tested in a bootstrap validation with 1,000 hypothetical datasets. This suggested the model’s good discrimination and prediction capability.