Long-term mortality and predictive score performance in Brazilian atherosclerotic renovascular disease patients
Description
Introduction: Atherosclerotic renovascular disease (ARVD) can cause renal artery stenosis, hypertension and chronic kidney disease. Revascularization is controversial and a risk score was developed to predict mortality in patients with ARVD, which required validation in other populations. The original risk score did not include statin use; the aim of this study was to evaluate its accuracy in ARVD patients according to statins intake. Methods: Longitudinal retrospective study involving 136 patients with angiographic diagnosis of RAS > 60% from January 1996 to October 2008. Cox Regression was performed to all-cause mortality associations. To evaluate discriminatory power of the risk score, ROC curves were constructed for mortality at 1, 5 and 10 years, for those with and without statin use. Results: 103 patients were included, 69 of whom were taking statins. After 1, 5 and 10 years, survival rates predicted by the risk score for patients using statins were, respectively, 0.87 (95% CI [0.76;0.97]), 0. 45 (95% CI [0.37;0.55]) and 0.15 (95% CI [0.09;0.22]). Actual survival rates were 0.95, 0.88 and 0.72. For the 34 patients who did not use statins, predicted survival rates were 0.84 (95% CI [0.71;0.97]), 0.43 (IC 95% [0.32;0.55]) and 0.14 (95% CI [0.05;0.22]); actual survival rates were 0.83, 0.36 and 0.29. Conclusion: Patients receiving statins had greater survival rates after 5 and 10 years when compared to calculations by the risk score. The 34 patients who did not use statins had survival rates close to predicted. The risk score should be modified to include use of statins.
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The present analysis was a retrospective study of ARVD patients managed in one Brazilian specialist Hypertension centre and the primary outcome was to evaluate all-cause mortality of patients with ARVD. This Brazilian cohort was previously analyzed by Hagemann et al. (10). Patients were evaluated using the risk score calculator developed by Vassallo et al. (11), to access the validity of the score in this cohort. Patients older than 18 years-old, with RAS > 60% of the renal artery diameter, unilaterally or bilaterally, as evidenced by direct catheter angiography, were included. Those with non-atherosclerotic RAS were excluded. Patients were analyzed according to baseline values for age, race, gender, smoking status, presence of diabetes mellitus (DM), CAD, peripheral arterial disease, chronic heart failure class as per New York Heart Association Classification, creatinine, estimated glomerular filtration rate (eGFR) by the CKD-EPI formula, proteinuria (24h urine protein excretion), renal revascularization, use of angiotensin converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB), use of statins and use of beta-blockers. To calculate the risk score as per Vassallo et al (11), the following variables were used: age, eGFR, proteinuria, prevalence of DM, whether or not the revascularization procedure was performed, history of myocardial infarction, left ventricular failure and peripheral artery disease. The study was approved by the Research Ethics Committee of the Faculdade de Medicina de Botucatu, Unesp, and the need for informed consent term was waived, because this was a retrospective study using anonymized data. Categorical variables were expressed as absolute values and percentages and continuous variables were expressed as mean ± standard deviation. Cox proportional regression was performed for the survival analysis. The survival probabilities predicted by the risk score for each patient were calculated within the risk score calculator, as well as the mean and 95% confidence intervals for one-, 5- and 10-year survival. The predicted probabilities were compared to the actual survival curves. These comparisons took note of whether patients were or were not taking statin therapy. A p value < 0.05 was considered statistically significant. The statistical software used was SPSS 25.0. All the data is included in an Excel spreadsheet containing the names of the patients and their characteristics, for example, age, sex, comorbidities and whether or not renal revascularization was performed.