A novel prognostic model for transplant-free survival in primary sclerosing cholangitis

Abstract

ObjectiveMost prognostic models for primary sclerosing cholangitis (PSC) are based on patients referred to tertiary care and may not be applicable for the majority of patients with PSC. The aim of this study was to construct and externally validate a novel, broadly applicable prognostic model for transplant-free survival in PSC, based on a large, predominantly population-based cohort using readily available variables.DesignThe derivation cohort consisted of 692 patients with PSC from the Netherlands, the validation cohort of 264 patients with PSC from the UK. Retrospectively, clinical and biochemical variables were collected. We derived the prognostic index from a multivariable Cox regression model in which predictors were selected and parameters were estimated using the least absolute shrinkage and selection operator. The composite end point of PSC-related death and liver transplantation was used. To quantify the models’ predictive value, we calculated the C-statistic as discrimination index and established its calibration accuracy by comparing predicted curves with Kaplan-Meier estimates.ResultsThe final model included the variables: PSC subtype, age at PSC diagnosis, albumin, platelets, aspartate aminotransferase, alkaline phosphatase and bilirubin. The C-statistic was 0.68 (95% CI 0.51 to 0.85). Calibration was satisfactory. The model was robust in the sense that the C-statistic did not change when prediction was based on biochemical variables collected at follow-up.ConclusionThe Amsterdam-Oxford model for PSC showed adequate performance in estimating PSC-related death and/or liver transplant in a predominantly population-based setting. The transplant-free survival probability can be recalculated when updated biochemical values are available.

Enhanced liver fibrosis test predicts transplant‐free survival in primary sclerosing cholangitis, a multi‐centre study

“…Recently, the novel Amsterdam-Oxford prognostic model for PSC was presented which was validated in an external PSC cohort, and is also applicable in early stage disease. [19] The ELF test showed a moderate correlation with the prognostic index of this model (including the variables PSC type, age at PSC diagnosis, albumin, platelets, aspartate aminotransferase, alkaline phosphatase and bilirubin), and calculation of the net reclassification index showed a significantly increased precision of predicting survival when adding ELF test results. These findings suggest that ELF test has an independent prognostic value in addition to current routine biomarkers, and that the combination of the ELF test and clinically derived prognostic models in PSC might yield increased prognostic power, and such composite models warrant further research.…”

“…There was a significant correlation between ELF test and the prognostic index of the Amsterdam-Oxford prognostic model [19] with a correlation coefficient of 0.537, p<0.001. The net reclassification index (NRI) of adding ELF test to this prognostic index was highly significant, when ELF test was added as a continuous variable or a categorical variable using the thresholds provided by the manufacturer (p<0.001 for both).…”

“…Correlation between the ELF test and the prognostic index as calculated by the novel Amsterdam-Oxford prognostic model including PSC type, age at PSC diagnosis, albumin, platelets, aspartate aminotransferase, alkaline phosphatase and bilirubin, [19] was assessed by Spearman's rank correlation test. To assess the additive value of ELF over routine biomarkers as used in the Amsterdam-Oxford model the prediction increment of the ELF test when added as a predictor to this prognostic model for PSC was calculated by the category-free net reclassification index.…”

Machine Learning in a Complex Disease: PREsTo Improves the Prognostication of Primary Sclerosing Cholangitis

“…In addition to PREsTo, other scores have been recently proposed, including the Amsterdam‐Oxford model (AOM) and the UK‐PSC risk score . The AOM, which predicts PSC‐related death or liver transplantation, was developed and internationally validated with recent work highlighting an incremental improvement in the model's performance over time (such as at 5 years after diagnosis) .…”

Prognosis of primary sclerosing cholangitis - time to look at the population as a whole, not only from the center's or waiting list perspective

“…After a median follow‐up of more than 9 years (110 months) in these 692 patients, PSC‐related death occurred in 10% of patients while 18% underwent liver transplantation. In the validation cohort of 264 patients with a median follow‐up of 103 months, PSC‐related death occurred in 14% while 7% underwent liver transplantation . The largest study to date analyzing the prognosis of patients with PSC was published last year.…”