Table 2.
Development of the new models
| Statistic | Baseline Model (KFRE) | New Model 1 (KFRE+RRI) | New Model 2 (KFRE+DI-RISK) | Validation cohort (KFRE+RRI) |
|---|---|---|---|---|
| Number of patients | 403 | 403 | 370 | 162 |
| Number with ESRD | 52 | 52 | 49 | 23 |
| Beta coefficients | ||||
| KFRE indexa | 0.827 (0.659–0.995) | 0.861 (0.676–1.05) | 0.832 (0.654–1.01) | 0.811 (0.446–1.18) |
| RRI per 5 units | 0.332 (0.149–0.515) | 0.198 (–0.113–0.510) | ||
| DI-RISK per 5 units | 0.223 (–0.027–0.473) | |||
| Hazard ratios | ||||
| KFRE indexa | 2.29 (1.93–2.71) | 2.37 (1.97–2.84) | 2.30 (1.92–2.74) | 2.25 (1.56–3.24) |
| RRI per 5 units | 1.39 (1.16–1.67) | 1.22 (0.89–1.67) | ||
| DI-RISK per 5 units | 1.25 (0.97–1.60) | |||
| R2 | 0.29 (37.7%) | 0.31 (40.7%) | 0.29 (38.4%) | 0.43 (57.3%) |
| c-statistic | 0.91 (0.83–0.99) | 0.91 (0.83–1.00) | 0.92 (0.83–1.00) | 0.95 (0.83–1.00) |
| Assessment censored at 3 years | ||||
| Number with ≥3 years follow up | 371 | 371 | ||
| Number with ESRD within 3 years | 29 | 29 | ||
| c-statistic (AUC) | 0.91 (0.87–0.95) | 0.92 (0.89–0.96) | ||
| Integrated Sensitivity | 0.31 (0.24–0.38) | 0.36 (0.27–0.45) | ||
| Integrated 1-Specificity | 0.06 (0.05–0.07) | 0.06 (0.04–0.07) | ||
| IDI No ESRD | 0.05 (0.00–0.10) | |||
| IDI ESRD | 0.00 (0.00–0.01) |
KFRE, Kidney Failure Risk Equation; RRI, renal resistive index; DI-RISK, difference of resistive indices in spleen and kidney; AUC, area under the curve; IDI No ESRD, integrated discrimination improvement metrics for patients without subsequent ESRD; IDI ESRD, integrated discrimination improvement metrics for patients with subsequent ESRD. c-statistic is Harrel’s c-statistic. R2 is presented as a proportion and percentage of the maximum possible R2.
a
KFRE index from Equation 1.