Incidence of cardiovascular events and associated risk factors in kidney transplant patients: a competing risks survival analysis

[Abstract] Background: The high prevalence of cardiovascular risk factors among the renal transplant population accounts for increased mortality. The aim of this study is to determine the incidence of cardiovascular events and factors associated with cardiovascular events in these patients. Methods: An observational ambispective follow-up study of renal transplant recipients (n = 2029) in the health district of A Coruña (Spain) during the period 1981-2011 was completed. Competing risk survival analysis methods were applied to estimate the cumulative incidence of developing cardiovascular events over time and to identify which characteristics were associated with the risk of these events. Post-transplant cardiovascular events are defined as the presence of myocardial infarction, invasive coronary artery therapy, cerebral vascular events, new-onset angina, congestive heart failure, rhythm disturbances, peripheral vascular disease and cardiovascular disease and death. The cause of death was identified through the medical history and death certificate using ICD9 (390-459, except: 427.5, 435, 446, 459.0). Results: The mean age of patients at the time of transplantation was 47.0 ± 14.2 years; 62% were male. 16.5% had suffered some cardiovascular disease prior to transplantation and 9.7% had suffered a cardiovascular event. The mean follow-up period for the patients with cardiovascular event was 3.5 ± 4.3 years. Applying competing risk methodology, it was observed that the accumulated incidence of the event was 5.0% one year after transplantation, 8.1% after five years, and 11.9% after ten years. After applying multivariate models, the variables with an independent effect for predicting cardiovascular events are: male sex, age of recipient, previous cardiovascular disorders, pre-transplant smoking and post-transplant diabetes. Conclusions: This study makes it possible to determine in kidney transplant patients, taking into account competitive events, the incidence of post-transplant cardiovascular events and the risk factors of these events. Modifiable risk factors are identified, owing to which, changes in said factors would have a bearing of the incidence of events

A randomized clinical trial to determine the effectiveness of CO-oximetry and anti-smoking brief advice in a cohort of kidney transplant patients who smoke: study protocol for a randomized controlled trial

Randomized controlled trial[Abstract]Background: The cardiovascular risk in renal transplant patients is increased in patients who continue to smoke after transplantation. The aim of the study is to measure the effectiveness of exhaled carbon monoxide (CO) measurement plus brief advisory sessions, in comparison to brief advice, to reduce smoking exposure and smoking behavior in kidney transplant recipients who smoke. The effectiveness will be measured by: (1) abandonment of smoking, (2) increase in motivation to stop smoking, and (3) reduction in the number of cigarettes smoked per day. Design: a randomized, controlled, open clinical trial with blinded evaluation. Scope: A Coruña Hospital (Spain), reference to renal transplantation in the period 2012-2015. Inclusion criteria: renal transplant patients who smoke in the precontemplation, contemplation or preparation stages according to the Prochaska and DiClemente's Stages of Change model, and who give their consent to participate. Exclusion criteria: smokers attempting to stop smoking, patients with terminal illness or mental disability that prevents them from participating. Randomization: patients will be randomized to the control group (brief advisory session) or the intervention group (brief advisory session plus measuring exhaled CO). The sample target size is n = 112, with 56 patients in each group. Allowing for up to 10 % loss to follow-up, this would provide 80 % power to detect a 13 % difference in attempting to give up smoking outcomes at a two-tailed significance level of 5 %. Measurements: sociodemographic characteristics, cardiovascular risk factors, treatment, rejection episodes, infections, self-reported smoking habit, drug use, level of dependence (the Fagerström test), stage of change (Prochaska and DiClemente's Stages of Change model), and motivation to giving up smoking (the Richmond test). Response: the effectiveness will be evaluated every 3, 6, 9 and 12 months as: pattern of tobacco use (self-reported tobacco use), smoking cessation rates, carbon monoxide (CO) levels in exhaled air measured by CO-oximetry, urinary cotinine tests, nicotine dependence (Fagerström test), motivational stages of change (Prochaska and DiClemente's stages) and motivation to stop smoking (the Richmond test). Analysis: descriptive statistics and linear/logistic multiple regression models will be performed. Clinical relevance will be measured as relative risk reduction, absolute risk reduction and the number needed to treat. Ethics: informed consent of the patients and Ethical Review Board was obtained (code 2011/061). Discussion: Tobacco is a modifiable risk factor that increase the risk of morbidity and mortality in kidney transplant recipients. If effectiveness of CO-oximetry is confirmed to reduce tobacco exposure, we would have an intervention that is easy to use, low cost and with great implications about cardiovascular risk prevention in these patients.Instituto de Salud Carlos III; PI11/0135

Incidence of cardiovascular events after kidney transplantation and cardiovascular risk scores: study protocol

[Abstract] Background: Cardiovascular disease (CVD) is the major cause of death after renal transplantation. Not only conventional CVD risk factors, but also transplant-specific risk factors can influence the development of CVD in kidney transplant recipients. The main objective of this study will be to determine the incidence of post-transplant CVD after renal transplantation and related factors. A secondary objective will be to examine the ability of standard cardiovascular risk scores (Framingham, REGICOR, SCORE, and DORICA) to predict post-transplantation cardiovascular events in renal transplant recipients, and to develop a new score for predicting the risk of CVD after kidney transplantation. Methods/design: Observational prospective cohort study of all kidney transplant recipients in the A Coruna Hospital (Spain) in the period 1981-2008 (2059 transplants corresponding to 1794 patients). The variables included will be: donor and recipient characteristics, chronic kidney disease-related risk factors, pre-transplant and post-transplant cardiovascular risk factors, routine biochemistry, and immunosuppressive, antihypertensive and lipid-lowering treatment. The events studied in the follow-up will be: patient and graft survival, acute rejection episodes and cardiovascular events (myocardial infarction, invasive coronary artery therapy, cerebral vascular events, new-onset angina, congestive heart failure, rhythm disturbances and peripheral vascular disease). Four cardiovascular risk scores were calculated at the time of transplantation: the Framingham score, the European Systematic Coronary Risk Evaluation (SCORE) equation, and the REGICOR (Registre Gironi del COR (Gerona Heart Registry)), and DORICA (Dyslipidemia, Obesity, and Cardiovascular Risk) functions. The cumulative incidence of cardiovascular events will be analyzed by competing risk survival methods. The clinical relevance of different variables will be calculated using the ARR (Absolute Risk Reduction), RRR (Relative Risk Reduction) and NNT (Number Needed to Treat). The ability of different cardiovascular risk scores to predict cardiovascular events will be analyzed by using the c index and the area under ROC curves. Based on the competing risks analysis, a nomogram to predict the probability of cardiovascular events after kidney transplantation will be developed. Discussion: This study will make it possible to determine the post-transplant incidence of cardiovascular events in a large cohort of renal transplant recipients in Spain, to confirm the relationship between traditional and transplant-specific cardiovascular risk factors and CVD, and to develop a score to predict the risk of CVD in these patients.Instituto de Salud Carlos III; PI070986Xunta de Galicia; PS09/26Insituto de Salud Carlos III; G03/170Instituto de Salud Carlos III; RD06/ 001

Randomized Clinical Trial to Determine the Effectiveness of CO-Oximetry and Anti-Smoking Brief Advice in a Cohort of Kidney Transplant Patients who Smoke

[Abstract] Background: measure the efficacy of exhaled carbon monoxide (CO) measurement plus brief advisory sessions to reduce smoking exposure and smoking behaviour in kidney transplant recipients. Methods: Randomized, controlled, open-label clinical trial at a Spanish hospital.Smoking kidney transplant recipients giving their consent to participate were randomized to control (brief advice, n=63) or intervention group (brief advisory session plus measuring exhaled CO, n=59). Measurements: Sociodemographic characteristics, cardiovascular risk factors, treatment, rejection episodes, infections, self-reported smoking, drug use, level of dependence and motivation to stop smoking (Fagerström's and Richmond's test) and stage of change (Prochaska and DiClemente's Stages). Efficacy was assessed at 3, 6, 9 and 12 months as: cotinine test, CO levels in exhaled air, nicotine dependence, motivational stages of change, motivation to stop smoking, pattern of tobacco use and smoking cessation rates. Logistic regression models were computed. Results: At 12 months of follow-up, differences were found in exhaled CO between the intervention and control group(6.1±6.8vs.10.2±9.7ppm;p=0.028). Carboxyhemoglobin levels were lower in the intervention group as well as the positive cotinine test (1.2±1.2%vs.2.0±2.4%;p=0.039),(53.4%vs.74.2%). At 12 months, intervention reduces the probability of a positive urine test by 28%. Conclusions: Co-oximetry is a clinically relevant intervention for reduction of tobacco exposure in kidney transplant recipients.Instituto de Salud Carlos III; PI11 /0135

Risk factors for graft loss and mortality after renal transplantation according to recipient age: a prospective multicentre study

Producción CientíficaBackground. To describe the causes of graft loss, patient death and survival figures in kidney transplant patients in Spain based on the recipient’s age. Methods. The results at 5 years of post-transplant cardiovascular disease (CVD) patients, taken from a database on CVD, were prospectively analysed, i.e. a total of 2600 transplanted patients during 2000–2002 in 14 Spanish renal transplant units, most of them receiving their organ from cadaver donors. Patients were grouped according to the recipient’s age: Group A: 60 years. The most frequent immunosuppressive regimen included tacrolimus, mycophenolate mofetil and steroids. Results. Patients were distributed as follows: 25.85% in Group A (>40 years), 50.9% in Group B (40–60 years) and 23.19% in Group C (>60). The 5-year survival for the different age groups was 97.4, 90.8 and 77.7%, respectively. Death-censored graft survival was 88, 84.2 and 79.1%, respectively, and non death-censored graft survival was 82.1, 80.3 and 64.7%, respectively. Across all age groups, CVD and infections were the most frequent cause of death. The main causes of graft loss were chronic allograft dysfunction in patients 1 g at 6 months post-transplantation were statistically significant in the three age groups. The patient survival multivariate analysis did not achieve a statistically significant common factor in the three age groups. Conclusions. Five-year results show an excellent recipient survival and graft survival, especially in the youngest age group. Death with functioning graft is the leading cause of graft loss in patients >40 years. Early improvement of renal function and proteinuria together with strict control of cardiovascular risk factors are mandatory

Renal transplantation in the modern immunosuppressive era in Spain: four-year results from a multicenter database focus on post-transplant cardiovascular disease

Producción CientíficaTo evaluate cardiovascular disease (CVD) after renal transplantation we established a CVD database (no-intervention) including all patients transplanted among 2000–2002 in 14 hospitals from Spain (Renal Forum Group) (n¼2600). They were prospective followed annually thereafter and we present herein the most important results concerning survival figures and CVD at four years. Mean recipient age was 49.7±13.7 years: 16% retransplanted and 12.5% hyperimmunized. Tacrolimus, mycophenolate mofetil, and steroids was used in 63%. Acute rejection (AR) rate at 1 year was 14.8%. Graft and patient survival at 48 months were 85.6% (death censored) and 91.7% respectively. The first cause of graft loss was vascular in the first year, death with function during the 2–3 years, and chronic allograft nephropathy at the 4th year. Donor age, time on dialysis, acute tubular necrosis (ATN), AR, SCr at 6 months, the use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers in the first year, and systolic blood pressure at 24 months were independent risk factors for graft loss at 4th year. The first cause of death was CVD (predominantly ischemic heart disease (IHD) in the first year). Recipient age, ATN, and SCr at 6 months were independent predictors of mortality. Despite worsening of donor age, comorbidity, and advanced age of recipients, survival figures at four years are considered good in our Spanish non-selected population. Cardiovascular mortality is the most important cause of death and graft loss particularly, IHD in the first year. Therefore, to decrease post-transplant mortality a careful cardiovascular evaluation and treatment in the waiting list and a close follow-up of patients after transplantation is mandatory

Incidence of cardiovascular events after kidney transplantation and cardiovascular risk scores: study protocol

<p>Abstract</p> <p>Background</p> <p>Cardiovascular disease (CVD) is the major cause of death after renal transplantation. Not only conventional CVD risk factors, but also transplant-specific risk factors can influence the development of CVD in kidney transplant recipients.</p> <p>The main objective of this study will be to determine the incidence of post-transplant CVD after renal transplantation and related factors. A secondary objective will be to examine the ability of standard cardiovascular risk scores (Framingham, Regicor, SCORE, and DORICA) to predict post-transplantation cardiovascular events in renal transplant recipients, and to develop a new score for predicting the risk of CVD after kidney transplantation.</p> <p>Methods/Design</p> <p>Observational prospective cohort study of all kidney transplant recipients in the A Coruña Hospital (Spain) in the period 1981-2008 (2059 transplants corresponding to 1794 patients).</p> <p>The variables included will be: donor and recipient characteristics, chronic kidney disease-related risk factors, pre-transplant and post-transplant cardiovascular risk factors, routine biochemistry, and immunosuppressive, antihypertensive and lipid-lowering treatment. The events studied in the follow-up will be: patient and graft survival, acute rejection episodes and cardiovascular events (myocardial infarction, invasive coronary artery therapy, cerebral vascular events, new-onset angina, congestive heart failure, rhythm disturbances and peripheral vascular disease).</p> <p>Four cardiovascular risk scores were calculated at the time of transplantation: the Framingham score, the European Systematic Coronary Risk Evaluation (SCORE) equation, and the REGICOR (Registre Gironí del COR (Gerona Heart Registry)), and DORICA (Dyslipidemia, Obesity, and Cardiovascular Risk) functions.</p> <p>The cumulative incidence of cardiovascular events will be analyzed by competing risk survival methods. The clinical relevance of different variables will be calculated using the ARR (Absolute Risk Reduction), RRR (Relative Risk Reduction) and NNT (Number Needed to Treat).</p> <p>The ability of different cardiovascular risk scores to predict cardiovascular events will be analyzed by using the c index and the area under ROC curves. Based on the competing risks analysis, a nomogram to predict the probability of cardiovascular events after kidney transplantation will be developed.</p> <p>Discussion</p> <p>This study will make it possible to determine the post-transplant incidence of cardiovascular events in a large cohort of renal transplant recipients in Spain, to confirm the relationship between traditional and transplant-specific cardiovascular risk factors and CVD, and to develop a score to predict the risk of CVD in these patients.</p

A randomized clinical trial to determine the effectiveness of CO-oximetry and anti-smoking brief advice in a cohort of kidney transplant patients who smoke: study protocol for a randomized controlled trial

BACKGROUND: The cardiovascular risk in renal transplant patients is increased in patients who continue to smoke after transplantation. The aim of the study is to measure the effectiveness of exhaled carbon monoxide (CO) measurement plus brief advisory sessions, in comparison to brief advice, to reduce smoking exposure and smoking behavior in kidney transplant recipients who smoke. The effectiveness will be measured by: (1) abandonment of smoking, (2) increase in motivation to stop smoking, and (3) reduction in the number of cigarettes smoked per day. METHODS/DESIGN: Design: a randomized, controlled, open clinical trial with blinded evaluation. Scope: A Coruña Hospital (Spain), reference to renal transplantation in the period 2012–2015. Inclusion criteria: renal transplant patients who smoke in the precontemplation, contemplation or preparation stages according to the Prochaska and DiClemente’s Stages of Change model, and who give their consent to participate. Exclusion criteria: smokers attempting to stop smoking, patients with terminal illness or mental disability that prevents them from participating. Randomization: patients will be randomized to the control group (brief advisory session) or the intervention group (brief advisory session plus measuring exhaled CO). The sample target size is n = 112, with 56 patients in each group. Allowing for up to 10 % loss to follow-up, this would provide 80 % power to detect a 13 % difference in attempting to give up smoking outcomes at a two-tailed significance level of 5 %. Measurements: sociodemographic characteristics, cardiovascular risk factors, treatment, rejection episodes, infections, self-reported smoking habit, drug use, level of dependence (the Fagerström test), stage of change (Prochaska and DiClemente’s Stages of Change model), and motivation to giving up smoking (the Richmond test). Response: the effectiveness will be evaluated every 3, 6, 9 and 12 months as: pattern of tobacco use (self-reported tobacco use), smoking cessation rates, carbon monoxide (CO) levels in exhaled air measured by CO-oximetry, urinary cotinine tests, nicotine dependence (Fagerström test), motivational stages of change (Prochaska and DiClemente’s stages) and motivation to stop smoking (the Richmond test). Analysis: descriptive statistics and linear/logistic multiple regression models will be performed. Clinical relevance will be measured as relative risk reduction, absolute risk reduction and the number needed to treat. Ethics: informed consent of the patients and Ethical Review Board was obtained (code 2011/061). DISCUSSION: Tobacco is a modifiable risk factor that increase the risk of morbidity and mortality in kidney transplant recipients. If effectiveness of CO-oximetry is confirmed to reduce tobacco exposure, we would have an intervention that is easy to use, low cost and with great implications about cardiovascular risk prevention in these patients. TRIAL REGISTRATION: Current Controlled Trials ISRCTN16615772. EudraCT number: 2015-002009-12