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Introduction: Chronic kidney disease prevention programs must identify patients at risk of early progression to provide better treatment and prolong kidney replacement therapy-free survival. Risk equations have been developed and validated in cohorts outside of Colombia, so this study aims to evaluate the discrimination and calibration of the four-variable kidney failure risk equation in a Colombian population where it has yet to be validated. Methods: External validation study of a kidney failure risk equation using a historical cohort of patients with CKD stages 3, 4, and 5, adults without a history of dialysis or kidney transplantation with a two-year follow-up, belonging to the Baxter Renal Care Services Colombia network. The discriminatory capacity of the model was evaluated by the concordance index using Harrell's C statistic, and the time-dependent area under the receiver operating characteristic (ROC) curve was estimated using the nearest neighbor method, as well as the optimal cut-off point for sensitivity and specificity. Calibration was determined by the degree of agreement between the observed outcome and the probabilities predicted by the model using the Hosmer-Lemeshow statistic. Results: A total of 5,477 patients were included, with a mean age of 72 years, 36.4% diabetic, and a mean baseline eGFR of 36 ml/min/1.73 m2. The rate of dialysis initiation was three events per 100 patient-years, 95% CI (2.9-3.6). The optimal cutoff for sensitivity was 0.94, for specificity, 0.76, and the area under the ROC curve was 0.92. Harrell's C-statistic was 0.88 for the total population, 0.88 for diabetic patients, and 0.93 for those 65 years or older. The validation of the model showed good calibration. Conclusions: In this Colombian cohort, the four-variable KFRE with a two-year prediction horizon has excellent calibration and discrimination, and its use in the care of CKD Colombian patients is recommended.
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BACKGROUND AND AIMS OF THE STUDY: This study investigated the efficacy of postoperative ticlopidine as antiplatelet therapy in patients shortly after heart valve repair or replacement. METHODS: Between 1990 and 1995, 235 consecutive patients underwent either valve repair (n = 67) or replacement with a bioprosthesis (n = 168). The bioprostheses used were Carpentier-Edwards porcine or pericardial (n = 158) valves, Prima stentless valves (n = 3) and cryopreserved homografts (n = 7). Types of repair were aortic (one), mitral annuloplasty with Carpentier ring (65) and tricuspid repair (one). Mean patient age was 67 (range: 16 to 83) years for valve replacement and 57 (range: 32 to 74) years for repair (p < 0.01). Atrial fibrillation occurred in 34% of patients. The hospital mortality rate was 11% (26 patients). Of the 209 survivors, 137 were assigned to antiplatelet treatment with ticlopidine for the first three months of follow up. The other 72 received either oral anticoagulation (coumadin; n = 40), aspirin (n = 14) or no medication (n = 18). In 15 patients, ticlopidine treatment was interrupted due to diarrhea (13 cases), mild allergic reaction (one) or anemia (one). The mean follow up was 3.2 years (range: 1 month to 6 years); cumulative follow up was 684 patient-years (pt-yr) and was complete in 96% of cases. RESULTS: There were two episodes of thromboembolism in the ticlopidine group at 1 month and 6 months respectively, with a linearized incidence of 0.5% pt-yr. In the coumadin group there were four episodes of thromboembolism, three within the first three months of follow up. The linearized incidence was 3% pt-yr (p < 0.01). There were three episodes of hemorrhage in the ticlopidine group in the first three months of follow up and one in the coumadin group. The linearized incidence was 0.75% pt-yr. CONCLUSIONS: Following heart valve repair or replacement with a bioprosthesis, the first three months is a high-risk period for thromboembolism. Ticlopidine seems to prevent this complication better than conventional therapy with oral anticoagulants. Nevertheless, hemorrhage continues to be a problem with ticlopidine therapy.
