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Updated: Jul 17, 2025

Assessment of Vascular Function in Patients With Chronic Kidney Disease
Published on: June 16, 2014
The Cardiovascular Literature-Based Risk Algorithm (CALIBRA): Predicting Cardiovascular Events in Patients With
Luca Neri1, Caterina Lonati2, Jasmine Ion Titapiccolo1
1Clinical and Data Intelligence Systems-Advanced Analytics, Fresenius Medical Care Deutschland GmbH, Vaiano Cremasco, Italy.
Insights
The new CArdiovascular, LIterature-Based, Risk Algorithm (CALIBRA) accurately predicts cardiovascular risk in chronic kidney disease (CKD) patients. CALIBRA outperforms existing models, offering improved risk stratification for better clinical management.
Area of Science:
- Nephrology
- Cardiology
- Biostatistics
Background:
- Cardiovascular disease (CVD) is the leading cause of mortality in chronic kidney disease (CKD) patients.
- Current risk prediction models are often inadequate for this population.
- Accurate CVD risk assessment is crucial for effective clinical management of CKD.
Purpose of the Study:
- To develop and validate a novel, literature-based risk prediction model for cardiovascular (CV) hospitalizations in CKD patients.
- To assess the performance of the new model, named CArdiovascular, LIterature-Based, Risk Algorithm (CALIBRA), against existing CV risk scores.
Main Methods:
- A literature-based, naïve-bayes model (CALIBRA) was developed incorporating 31 traditional and CKD-specific risk factors.
- CALIBRA was validated in two independent CKD cohorts: the FMC NephroCare (EuCliD®) and the German Chronic Kidney Disease (GCKD) study.
- Model performance was evaluated using c-statistics and calibration, with comparisons to Framingham Heart Study (FHS), ASCVD, and INDANA risk scores.
Main Results:
- CALIBRA demonstrated good discrimination in both validation cohorts (AUC 0.79 in EuCliD®, 0.73 in GCKD).
- CALIBRA showed significantly improved accuracy over FHS, ASCVD, and INDANA in both cohorts (ΔAUC ranging from -0.04 to -0.22).
- The model maintained accuracy even with missing data, indicating robustness in real-world settings.
Conclusions:
- CALIBRA offers accurate and robust cardiovascular risk stratification for CKD patients.
- The model provides superior predictive accuracy compared to established CV risk scores.
- CALIBRA's generalizability across diverse CKD populations and clinical settings is supported by the findings.
Background And Objectives:
Cardiovascular (CV) disease is the main cause of morbidity and mortality in patients suffering from chronic kidney disease (CKD). Although it is widely recognized that CV risk assessment represents an essential prerequisite for clinical management, existing prognostic models appear not to be entirely adequate for CKD patients. We derived a literature-based, naïve-bayes model predicting the yearly risk of CV hospitalizations among patients suffering from CKD, referred as the CArdiovascular, LIterature-Based, Risk Algorithm (CALIBRA).
Methods:
CALIBRA incorporates 31 variables including traditional and CKD-specific risk factors. It was validated in two independent CKD populations: the FMC NephroCare cohort (European Clinical Database, EuCliD®) and the German Chronic Kidney Disease (GCKD) study prospective cohort. CALIBRA performance was evaluated by c-statistics and calibration charts. In addition, CALIBRA discrimination was compared with that of three validated tools currently used for CV prediction in CKD, namely the Framingham Heart Study (FHS) risk score, the atherosclerotic cardiovascular disease risk score (ASCVD), and the Individual Data Analysis of Antihypertensive Intervention Trials (INDANA) calculator. Superiority was defined as a ΔAUC>0.05.
Results:
CALIBRA showed good discrimination in both the EuCliD® medical registry (AUC 0.79, 95%CI 0.76-0.81) and the GCKD cohort (AUC 0.73, 95%CI 0.70-0.76). CALIBRA demonstrated improved accuracy compared to the benchmark models in EuCliD® (FHS: ΔAUC=-0.22, p<0.001; ASCVD: ΔAUC=-0.17, p<0.001; INDANA: ΔAUC=-0.14, p<0.001) and GCKD (FHS: ΔAUC=-0.16, p<0.001; ASCVD: ΔAUC=-0.12, p<0.001; INDANA: ΔAUC=-0.04, p<0.001) populations. Accuracy of the CALIBRA score was stable also for patients showing missing variables.
Conclusion:
CALIBRA provides accurate and robust stratification of CKD patients according to CV risk and allows score calculations with improved accuracy compared to established CV risk scores also in real-world clinical cohorts with considerable missingness rates. Our results support the generalizability of CALIBRA across different CKD populations and clinical settings.
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Acute Kidney Injury II: Pathophysiology

