Reverse Epidemiology: A Confusing, Confounding, and Inaccurate Term

The U-shaped association of non-high-density lipoprotein cholesterol with all-cause and cardiovascular mortality in general adult population

Background

Non-high-density lipoprotein cholesterol (non-HDL-C) has been associated with atherosclerosis. However, the association between non-HDL-C and mortality in adult population remains unclear. We intended to investigate the association of non-HDL-C with cardiovascular and all-cause mortality using national representative data.

Methods

The study included 32,405 participants from the National Health and Nutrition Examination Survey (1999-2014). Mortality outcomes were ascertained by linkage to National Death Index records through December 31, 2015. Multivariable-adjusted Cox regression models were used to evaluate hazard ratio (HR) and 95% confidence interval (CI) of non-HDL-C concentrations in quintiles. Two-piecewise linear regression and restricted cubic spline analyzes were performed to test dose-response associations.

Results

After a median follow-up of 98.40  months, 2,859 (8.82%) all-cause and 551 (1.70%) cardiovascular deaths occurred. Compared with the highest group, the multivariable-adjusted hazard ratio (HR) of the first quintile for all-cause mortality was 1.53 (95%CI, 1.35-1.74). Higher non-HDL-C above a cutoff value of 4.9 mmol/L was related with cardiovascular mortality (HR = 1.33, 95%CI, 1.13-1.57). A U-shaped relationship between non-HDL-C and all-cause mortality was found in spline analysis with a cutoff value around 4 mmol/L. Similar results in subgroups analyzes were found among male, non-white population, participants who were not taking lipid-lowering drugs, and with body mass index (BMI) <25 kg/m².

Conclusion

Our findings suggest a U-shaped association between non-HDL-C and mortality among adult population.

Non-High-Density Lipoprotein Cholesterol and Cardiovascular Outcomes in Chronic Kidney Disease: Results from KNOW-CKD Study

As non-high-density lipoprotein cholesterol (non-HDL-C) levels account for all atherogenic lipoproteins, serum non-HDL-C level has been suggested to be a marker for cardiovascular (CV) risk stratification. Therefore, to unveil the association of serum non-HDL-C levels with CV outcomes in patients with non-dialysis chronic kidney disease (ND-CKD), the patients at stages 1 to 5 (n = 2152) from the Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease (KNOW-CKD) were prospectively analyzed. The subjects were divided into quintiles by serum non-HDL-C level. The primary outcome was a composite of all-cause death or non-fatal CV events. The median duration of follow-up was 6.940 years. The analysis using the Cox proportional hazard model unveiled that the composite CV event was significantly increased in the 5th quintile (adjusted hazard ratio 2.162, 95% confidence interval 1.174 to 3.981), compared to that of the 3rd quintile. A fully adjusted cubic spline model depicted a non-linear, J-shaped association between non-HDL-C and the risk of a composite CV event. The association remained robust in a series of sensitivity analyses, including the analysis of a cause-specific hazard model. Subgroup analyses reveled that the association is not significantly altered by clinical conditions, including age, gender, body mass index, estimated glomerular filtration rate, and albuminuria. In conclusion, high serum non-HDL-C level increased the risk of adverse CV outcomes among the patients with ND-CKD. Further studies are warranted to define the optimal target range of non-HDL-C levels in this population.

Obesity in cases undergoing the surgical procedure of lung lobectomy: risk or benefit?

OBJECTIVE

The aim of the study was to evaluate the effect of body mass index on patients' short-term results following lung lobectomy.

METHODS

In this retrospective study, we compared the perioperative and short-term postoperative results of obese (BMI≥30 kg/m2) versus non-obese patients (BMI<30 kg/m2) who underwent anatomical lung resection for cancer. The two groups had the same distribution of input risk factors and the same ratio of surgical approaches (thoracoscopy vs. thoracotomy).

RESULTS

The study included a total of 144 patients: 48 obese and 96 non-obese patients. Both groups had the same ratio of thoracoscopic vs. thoracotomy approach (50/50%), and were comparable in terms of demographics and clinical data. The g roups did not significantly differ in the frequency of perioperative or postoperative complications. Postoperative morbidity was higher among non-obese patients (34.4 vs. 27.1%), but this difference was not statistically significant (p=0.053). Hospital stay was similar in both study groups (p=0.100). Surgery time was significantly longer among obese patients (p=0.133). Postoperative mortality was comparable between the study groups (p=0.167).

CONCLUSIONS

Obesity does not increase the frequency of perioperative and postoperative complications in patients after lung lobectomy. The slightly better results in obese patients suggest that obesity may have some protective role.

Effect of diabetes mellitus on markers of left ventricular dysfunction in chronic kidney disease

OBJECTIVES

To identify markers of left ventricular dysfunction in chronic kidney disease (CKD) and the effects of diabetes mellitus on them.

METHODS

This was a cross sectional study of 200 consecutive chronic kidney disease patients (stage III-V). Echocardiographic assessment of left ventricular function including left ventricular ejection fraction (LVEF), left ventricular mass index (LVMI), left atrial volume, grade of diastolic dysfunction, E/E', left and right ventricular myocardial performance indices (LVMPI, RVMPI) were compared between diabetic and non-diabetic CKD.

RESULTS

LVMI significantly increased with increasing stage of CKD (p < 0.001) in both diabetics (158.82 ± 48.76 gm/m2 in stage III to 201.06 ± 63.62 gm/m2 in stage V) and non-diabetics (133.14 ± 43.06 gm/m2 stage III to 196.24 ± 58.75 gm/m2 in stage V). This was significantly higher among diabetics of similar CKD stage compared to non-diabetics (p = 0.001). The LVEF worsened with increasing stage of CKD (p = 0.002) and was significantly reduced in diabetic patients (LVEF 61.96 ± 8.48 % in stage III CKD to 51.62 ± 13.45 % in stage V CKD) (p < 0.001). Diastolic dysfunction (Grades ≥2) and LA volume increased significantly with stage of CKD (p < 0.001) and was higher among diabetics (p = 0.048). Pulmonary artery systolic pressure (PASP) increased with increasing stage of CKD (p < 0.001), and was higher among diabetics (p = 0.035). E/E' worsened significantly with increasing stage of CKD and was also significantly higher in diabetics (p < 0.001). LVMPI (p < 0.001) and RVMPI (p < 0.001) were significantly reduced with worsening stage of CKD and in diabetics.

CONCLUSION

Advancing CKD stage was linearly associated with progressive left ventricular dysfunction which was significantly greater in diabetics.

Calcium channel blockers, survival and ischaemic stroke in patients with dementia: a Swedish registry study

BACKGROUND

The effect of calcium channel blockers (CCB) on mortality and ischaemic stroke risk in dementia patients is understudied.

OBJECTIVES

To calculate the risk of death and ischaemic stroke in dementia patients treated with CCBs, considering individual agents and dose response.

METHODS

Longitudinal cohort study with 18 906 hypertensive dementia patients from the Swedish Dementia Registry (SveDem), 2008-2014. Other Swedish national registries contributed information on comorbidities, dispensed medication and outcomes. Individual CCB agents and cumulative defined daily doses (cDDD) were considered.

RESULTS

In patients with hypertension and dementia, nifedipine was associated with increased mortality risk (aHR 1.32; CI 1.01-1.73; P < 0.05) compared to non-CCB users. Patients diagnosed with Alzheimer's dementia (AD) or dementia with Lewy bodies/Parkinson's disease dementia (DLB-PDD) taking amlodipine had lower mortality risk (aHR, 0.89; CI, 0.80-0.98; P < 0.05 and aHR 0.58; CI, 0.38-0.86; P < 0.01, respectively), than those taking other CCBs. Amlodipine was associated with lower stroke risk in patients with Alzheimer's dementia compared to other CCBs (aHR 0.63; CI, 0.44-0.89; P < 0.05). Sensitivity analyses with propensity score-matched cohorts repeated the results for nifedipine (aHR 1.35; 95% CI, 1.02-1.78; P < 0.05) and amlodipine in AD (aHR, 0.87; CI, 0.78-0.97; P < 0.05) and DLB-PDD (aHR, 0.56, 95%CI, 0.37-0.85; P < 0.05).

CONCLUSION

Amlodipine was associated with reduced mortality risk in dementia patients diagnosed with AD and DLB-PDD. AD patients using amlodipine had a lower risk of ischaemic stroke compared to other CCB users.

Under-Recognizing Malnutrition in Hospitalized Obese Populations: The Real Paradox

PURPOSE OF REVIEW

Obesity and malnutrition are frequently encountered in the hospitalized population. Although malnutrition associated with low or normal body mass index (BMI) is easily identified, malnutrition in obese patients goes frequently unrecognized as their fat mass masks underlying muscle mass deterioration. The purpose of this review is to explore if malnutrition has been studied in the obese hospitalized population and if that may be one of the reasons for the variable results in the obesity outcome data.

RECENT FINDINGS

Various studies have shown a conflicting association between obesity and outcomes in hospitalized patient population. Most prior studies used BMI alone as an indicator of obesity and although some recent studies have included body fat percentage, muscle mass, and functional status, they still showed variable outcomes. Unfortunately, there are not many studies that looked into nutrition status specifically in obese patients to study the outcomes. Studies evaluating clinical outcomes in obese patients showed a wide range of outcomes; some showed a protective effect while others were neutral. We explored recent data about obesity, malnutrition, and outcomes, where researchers more precisely defined malnutrition and obesity to determine health outcomes.

There is a U shaped association between non high density lipoprotein cholesterol with overall and cardiovascular mortality in chronic kidney disease stage 3-5

Dyslipidemia is common in patients with chronic kidney disease (CKD), however the relationship between dyslipidemia and mortality in patients with moderate to severe CKD remains controversial. Non-high-density lipoprotein (HDL) cholesterol has been reported to be a more accurate predictor of clinical outcomes than conventional lipid measurements. Hence, the aim of this study was to investigate associations between non-HDL cholesterol and the risk of overall and cardiovascular mortality in patients with CKD stage 3–5. We enrolled 429 pre-dialysis patients with stage 3 to 5 CKD from May 2006 to January 2010. The patients were divided into four groups according to quartiles of non-HDL cholesterol. The patients were followed until death or until January 2020. During a median 11.6 years of follow-up, there were 78 (18.2%) deaths overall and 32 (7.5%) cardiovascular deaths. In adjusted models, the patients in quartile 1 (hazard ratio [HR] 3.368; 95% confidence interval [CI] 1.388–8.176; p = 0.007), quartile 3 (HR 3.666; 95% CI 1.486–9.044; p = 0.005), and quartile 4 (HR 2.868; 95% CI 1.136–7.240; p = 0.026) of non-HDL cholesterol had a higher risk of overall mortality (vs. quartile 2). In addition, the patients in quartile 1 (HR 19.503; 95% CI 2.185–174.0925 p = 0.008), quartile 3 (HR 28.702; 95% CI 2.990–275.559; p = 0.004), and quartile 4 (HR 11.136; 95% CI 1.126–110.108; p = 0.039) had a higher risk of cardiovascular mortality (vs. quartile 2). Our study showed a U-shaped relationship between non-HDL cholesterol and the risk of overall and cardiovascular mortality in patients with CKD stage 3–5. Assessing non-HDL cholesterol may help to identify subjects at high-risk of adverse outcomes.

Statin use and Vital Organ Failure in Patients With Asthma-Chronic Obstructive Pulmonary Disease Overlap: A Time-Dependent Population-Based Study

Objective: The effects of statins on the risk of hepatic, renal, respiratory, and heart failure among patients with asthma–chronic obstructive pulmonary disease overlap (ACO) have not been reported.

Design: Time-dependent population-based study.

Setting: Patient data from 2000 to 2010 were retrieved from the Taiwan National Health Insurance Research Database.

Patients: We divided patients with ACO into cohorts of statin use (N = 1,211) and nonuse (N = 7,443).

Measurements and Main Results: The cumulative incidence rates of hepatic, renal, respiratory, and heart failure were analyzed through Cox proportional regression analysis with time-dependent variables. After adjustment for multiple confounding factors, including age, sex, comorbidities, and medications [statins, inhaled corticosteroid (ICS), or oral steroid (OS)], the adjusted hazard ratios (aHRs) [95% confidence intervals (CIs)] for hepatic, renal, respiratory, and heart failure were 0.50 (0.40–0.64), 0.49 (0.38–0.64), 0.61 (0.27–2.21), and 0.47 (0.37–0.60), respectively. The aHRs (95% CIs) for statin use with [ICS, OS] for hepatic, renal, and heart failure were [0.36 (0.20–0.66), 0.52 (0.39–0.70)]; [0.82 (0.51–1.34), 0.46 (0.33–0.63)]; and [0.66 (0.40–1.07), 0.48 (0.37–0.64)], respectively.

Conclusions: The ACO cohort with statin use exhibited lower risk of hepatic, renal, and heart failure than any other cohort, regardless of age, sex, comorbidities, or ICS or OS use. Regarding the combined use of statins and ICS, the risks of hepatic failure were lower. For the combined use of statins and OS, hepatic, renal, and heart failure were less frequent.

Connecting the brain cholesterol and renin-angiotensin systems: potential role of statins and RAS-modifying medications in dementia

Millions of people worldwide receive agents targeting the renin-angiotensin system (RAS) to treat hypertension or statins to lower cholesterol. The RAS and cholesterol metabolic pathways in the brain are autonomous from their systemic counterparts and are interrelated through the cholesterol metabolite 27-hydroxycholesterol (27-OHC). These systems contribute to memory and dementia pathogenesis through interference in the amyloid-beta cascade, vascular mechanisms, glucose metabolism, apoptosis, neuroinflammation and oxidative stress. Previous studies examining the relationship between these treatments and cognition and dementia risk have produced inconsistent results. Defining the blood-brain barrier penetration of these medications has been challenging, and the mechanisms of action on cognition are not clearly established. Potential biases are apparent in epidemiological and clinical studies, such as reverse epidemiology, indication bias, problems defining medication exposure, uncertain and changing doses, and inappropriate grouping of outcomes and medications. This review summarizes current knowledge of the brain cholesterol and RAS metabolism and the mechanisms by which these pathways affect neurodegeneration. The putative mechanisms of action of statins and medications inhibiting the RAS will be examined, together with prior clinical and animal studies on their effects on cognition. We review prior epidemiological studies, analysing their strengths and biases, and identify areas for future research. Understanding the pathophysiology of the brain cholesterol system and RAS and their links to neurodegeneration has enormous potential. In future, well-designed epidemiological studies could identify potential treatments for Alzheimer's disease (AD) amongst medications that are already in use for other indications.

Obesity paradox in patients undergoing lung lobectomy - myth or reality?

Background

The aim of the present study was to evaluate the impact of BMI on the short-term outcomes of patients undergoing lung lobectomy.

Methods

This was a retrospective clinical cohort study conducted in a single institution to assess the short-term outcomes of obese patients undergoing lung resection. Intraoperative and postoperative parameters were compared between the two study subgroups: obese (BMI ≥30 kg/m2) and non-obese patients (BMI < 30 kg/m2).

Results

In total, 203 patients were enrolled in the study (70 obese and 133 non-obese patients). Both study subgroups were comparable with regards to demographics, clinical data and surgical approach (thoracoscopy vs. thoracotomy). The surgery time was significantly longer in obese patients (p = 0.048). There was no difference in the frequency of intraoperative complications between the study subgroups (p = 0.635).

The postoperative hospital stay was similar in both study subgroups (p = 0.366). A 30-day postoperative morbidity was higher in a subgroup of non-obese patients (33.8% vs. 21.7%), but the difference was not significant (p = 0.249). In the subgroup of non-obese patients, a higher frequency of mild and severe postoperative complications was observed. However, the differences between the study subgroups were not statistically significant due to the borderline p-value (p = 0.053). The 30-day postoperative mortality was comparable between obese and non-obese patients (p = 0.167).

Conclusions

Obesity does not increase the incidence and severity of intraoperative and postoperative complications after lung lobectomy. Slightly better outcomes in obese patients indicate that obesity paradox might be a reality in patients undergoing lung resection.

Risk factors of prognosis after acute kidney injury in hospitalized patients

The risk factors, especially laboratory indicators, of prognosis after acute kidney injury (AKI) remain unclear. We conducted a retrospective survey of Chinese People's Liberation Army General Hospital from January 1, 2012 to December 31, 2012 according to the AKI diagnosis standard issued by Kidney Disease Improving Global Outcomes. The epidemiological features and factors influencing hospital mortality and renal function recovery were evaluated through logistic regression analysis. Among 77 662 cases of hospitalized patients, 1387 suffered from AKI. The incidence rate and mortality of AKI were 1.79% and 14.56%, respectively. Multivariate logistic regression analysis revealed that high AKI stage, age greater than 80 years, neoplastic disease, low cardiac output, increased white blood cell count, and decreased platelet count and serum albumin levels were the risk factors affecting the mortality of AKI patients. Conversely, body mass index between 28 and 34.9 was a protective factor. Increased AKI stage, tumor disease, post-cardiopulmonary resuscitation, and RRT were the risk factors of renal function recovery upon discharge. In addition to traditional risk factors, white blood cell count, platelet count, albumin, and BMI were the predictors of the mortality of AKI patients. No laboratory indicators were found to be the risk factors of renal function recovery in AKI patients.

Level of inflammatory factors in chronic hemodialysis patients with and without cardiovascular disease

Background:

Considering the existence of controversies about the predictive value of inflammatory markers for cardiovascular disease (CVD), we aimed to compare the level of high-sensitivity C-reactive protein (hs-CRP) and interlukin-6 (IL-6) level in chronic hemodialysis (HD) patients with and without CVD.

Materials and Methods:

In this historical cohort study, HD patients with and without CVD disease were enrolled. The presence of CVD risk factors, level of inflammatory factors including IL-6 and hs-CRP as well as lipid levels, fasting blood sugar, and other biochemical factors were compared in two studied groups.

Results:

During the study, eighty HD patients with (n = 40) and without (n = 40) CVD were enrolled. Diabetes was more prevalent among HD patients with CVD than those without CVD (P < 0.05). The level of IL-6 and hs-CRP were not different in two studied groups (P > 0.05). Univariate analysis of variance test indicated that there was not any significant relationship between hs-CRP and CVD (P > 0.05).

Conclusion:

The findings indicated that the level of inflammatory factors including hs-CRP and IL-6 are not significantly different in HD patients with and without CVD. However, for obtaining more definite conclusion in this field and evaluation their predicting role in this field, it is recommended to study other novel inflammatory markers as well as the additive effect of the inflammatory factors with traditional ones in larger sample size and longer follow-up.

Association of diabetes mellitus with decline in ankle-brachial index among patients on hemodialysis: A 6-year follow-up study

Peripheral artery occlusive disease is common among diabetes mellitus (DM) and end-stage renal disease patients, and tends to progress faster and lead to worse outcomes. This study compared the association of DM with the decline in ankle-brachial index (ABI) among patients on hemodialysis (HD). This was a longitudinal analysis of ABI in HD patients from 2009 to 2015. Medical records and yearly ABI values were obtained. A longitudinal mixed-model analysis was used to evaluate ABI changing trends while accounting for within-patients correlation. There were 296 patients on HD in the period of 2009-2015. In a 6-year follow-up, those with DM had a more rapid ABI decline compared to non-DM patients (slopes: -0.014 vs. 0.010 per year, interaction p < 0.001). In DM patients, female sex, high pulse pressure, high triglyceride, low creatinine, and high uric acid were associated with a decrease in ABI. In non-DM patients, old age, high pulse pressure, high low-density lipoprotein cholesterol, and high uric acid were associated with a decreased in ABI. There were 49.6% of patients with a normal ABI experienced a decrease at least 0.1 of ABI from baseline, and 35.3% had a final ABI < 0.9 in patients with a baseline ABI ≥ 0.9 (n = 232). In this study, DM patients on HD tend to develop a more rapid decline in ABI than non-DM patients on HD. Age, sex, pulse pressure, lipid profile, creatinine, and uric acid are associated with a decreased in ABI.

Identifying Potential Biases in the Nephrology Literature

Observational studies are common in the nephrology literature, particularly given the lack of large randomized trials. While these studies have identified important associations, potential biases, if unrecognized, can result in misinterpreted conclusions. In this review, we present an example of four potentially important biases (lead time bias, survivor bias, immortal time bias, and index event bias) that can result in inaccurate estimates of association between risk factors or treatments and outcomes. Recognition of these potential biases can help improve study design and interpretation.

Small dense low-density lipoprotein cholesterol was associated with future cardiovascular events in chronic kidney disease patients

Background

Cardiovascular disease (CVD) is often comorbid with chronic kidney disease (CKD). Small low-density lipoprotein cholesterol (sdLDL-C) has also been found to increase risk for CVD. The goal of the present study was to determine the nature of the relationship between sdLDL-C concentration and CVD in patients with CKD.

Methods

One-hundred and forty-five subjects (113 men and 32 women) with CKD (Stage 3 and Stage 4) participated this retrospective study. The concentration of sdLDL-C was measured in samples from 145 CKD patients between 2010 and 2012 during a four-year follow-up period.

Results

A total of eight fatal cardiovascular events (CVs) and 46 nonfatal CVs were registered in the four-year follow-up period. Multivariate Cox regression analysis showed that sdLDL-C [1.278, 95 % (1.019–1.598)] and sdLDL-C/LDL-C [2.456, 95 % (1.421–15.784)], at final observation, were independent risks of CVs. A Kaplan-Meier survival analysis showed that patients with sdLDL-C >38 mg/dl (logrank: 4.375, P = 0.037), and sdLDL-C/LDL-C ratio >0.3 levels (logrank: 11.94, P = 0.018) were at increased risk for CVs.

Conclusion

The results of this study indicated that for patients suffering CKD, a significant relationship exists between an elevated sdLDL-C concentration and the risk of cardiovascular disease.

Impact of Body Mass Index on Short-Term Outcomes in Patients Undergoing Percutaneous Coronary Intervention in Newfoundland and Labrador, Canada

Background and Aim. Obesity (BMI ≥ 30 kg/m²) is associated with advanced cardiovascular disease requiring procedures such as percutaneous coronary intervention (PCI). Studies report better outcomes in obese patients having these procedures but results are conflicting or inconsistent. Newfoundland and Labrador (NL) has the highest rate of obesity in Canada. The aim of the study was to examine the relationship between BMI and vascular and nonvascular complications in patients undergoing PCI in NL. Methods. We studied 6473 patients identified in the APPROACH-NL database who underwent PCI from May 2006 to December 2013. BMI categories included normal, 18.5 ≤ BMI < 25.0 (n = 1073); overweight, 25.0 ≤ BMI < 30 (n = 2608); and obese, BMI ≥ 30.0 (n = 2792). Results. Patients with obesity were younger and had a higher incidence of diabetes, hypertension, and family history of cardiac disease. Obese patients experienced less vascular complications (normal, overweight, and obese: 8.2%, 7.2%, and 5.3%, p = 0.001). No significant differences were observed for in-lab (4.0%, 3.3%, and 3.1%, p = 0.386) or postprocedural (1.0%, 0.8%, and 0.9%, p = 0.725) nonvascular complications. After adjusting for covariates, BMI was not a significant factor associated with adverse outcomes. Conclusion. Overweight and obesity were not independent correlates of short-term vascular and nonvascular complications among patients undergoing PCI.

Interankle systolic blood pressure difference and renal outcomes in patients with chronic kidney disease

AIM

Interankle blood pressure (BP) difference has been associated with peripheral artery disease and adverse cardiovascular outcomes. However, the relationship between interankle BP difference and renal outcomes in chronic kidney disease (CKD) has never been evaluated. The purpose of this study was to determine whether interankle BP difference is associated with the rate of renal function decline and progression to renal end points in patients with stage 3-5 CKD.

METHODS

We enrolled 144 patients with CKD from one regional hospital. The BP in four limbs was simultaneously measured using an ABI-form device. The decline in renal function was evaluated using an estimated glomerular filtration rate (eGFR) slope. Rapid renal progression was defined as an eGFR slope < -3 mL/min per 1.73 m(2) per year. The renal end points were defined as ≥ 25% decline in eGFR or commencement of dialysis during the follow-up period.

RESULTS

During a mean follow-up period of 3.1 years, 90 patients (62.5%) reached renal end points. Multivariate analysis showed that an increased interankle systolic BP difference (per 5 mmHg) was associated with a worse eGFR slope (regression β, -0.292; 95% confidence interval [CI], -0.482 to -0.102; P = 0.003), rapid renal progression (odds ratio, 1.189; 95% CI, 1.015-1.394; P = 0.032), and an increased risk of progression to renal end points (hazard ratio, 1.126; 95% CI, 1.052-1.204, P = 0.001).

CONCLUSION

Interankle systolic BP difference was associated with rapid renal progression and progression to renal end points in patients with stage 3-5 CKD in our study.

Moderator's view: Pretransplant weight loss in dialysis patients: cum grano salis

A high Body Mass Index (BMI) predicts delayed graft function, all cause and cardiovascular death after transplantation but such risk excess is apparently confined to patients included in studies performed before 2000. Perhaps with the exception of morbid obesity (BMI > 40), clinical outcomes in transplanted obese patients are definitely better than in listed dialysis patients who don't receive a renal transplant. Furthermore the new Scientific Registry of Transplant Recipients (SRTR) risk calculator incorporates BMI into the prediction model of the global risk for the graft's and patient's survival appropriately framing the risk of obesity in a multidimensional risk context. In the aggregate, available knowledge suggests that clinical decisions on weight loss before transplantation should be context specific. Renal transplant patients from living donors have substantial better survival in comparison to well matched dialysis patients listed for the same intervention at all BMI categories. Therefore renal transplantation in obese patients with a living donor may be prioritized. The attitude of fully informed obese patients at accepting the risk driven by transplantation, the experience of the surgical team with obese patients (including also robotic surgery) are of obvious importance. Renal transplantation should be timely considered when reasonable attempts at weight loss failed or appear overtly unrealistic. Transplantation in morbidly obese patients with BMI > 40, a category where the survival advantage of transplantation vs dialysis is probably small and still uncertain, particularly so in African-Americans, should be deferred until significant weight loss is achieved.

The role of plasma triglyceride/high-density lipoprotein cholesterol ratio to predict cardiovascular outcomes in chronic kidney disease

Background

Cardiovascular disease (CVD) risk is substantially increased in subjects with chronic kidney disease (CKD). The Triglycerides (TG) to High-Density Lipoprotein Cholesterol (HDL-C) ratio is an indirect measure of insulin resistance and an independent predictor of cardiovascular risk. No study to date has been performed to evaluate whether the TG/HDL-C ratio predicts CVD risk in patients with CKD.

Methods

A total of 197 patients (age 53 ± 12 years) with CKD Stages 1 to 5, were enrolled in this longitudinal, observational, retrospective study. TG/HDL-C ratio, HOMA-IR indexes, serum asymmetric dimethyl arginine (ADMA), high sensitivity C-reactive protein (CRP), parathyroid hormone (PTH), calcium, phosphorous, estimated glomerular filtration rate (eGFR), and albumin levels were measured. Flow mediated vasodilatation (FMD) of the brachial artery was assessed by using high-resolution ultrasonography.

Results

A total of 11 cardiovascular (CV) deaths and 43 nonfatal CV events were registered in a mean follow-up period of 30 (range 9 to 35) months. Subjects with TG/HDL-C ratios above the median values (>3.29) had significantly higher plasma ADMA, PTH, and phosphorous levels (p = 0.04, p = 0.02, p = 0.01 respectively) and lower eGFR and FMD values (p = 0.03, p < 0.001 respectively). The TG/HDL-C ratio was an independent determinant of FMD (β = −0.25 p = 0.02) along with TG, HDL-C, hsCRP, serum albumin, phosphate levels, systolic blood pressure, PTH, eGFR and the presence of diabetes mellitus. The TG/HDL-C ratio was also a significant independent determinant of cardiovascular outcomes [HR: 1.36 (1.11-1.67) (p = 0.003)] along with plasma ADMA levels [HR: 1.31 (1.13-1.52) (p < 0.001)] and a history of diabetes mellitus [HR: 4.82 (2.80-8.37) (p < 0.001)].

Conclusion

This study demonstrates that the elevated TG/HDL-C ratio predicts poor CVD outcome in subjects with CKD. Being a simple, inexpensive, and reproducible marker of CVD risk, the TG/HDL-C ratio may emerge as a novel and reliable indicator among the many well-established markers of CVD risk in CKD.

Systematic review registration

Clinical trial registration number and date: NCT02113462 / 10-04-2014.

Reverse epidemiology in different stages of heart failure

BACKGROUND

In heart failure (HF), traditional cardiovascular risk factors (RF) as body mass index (BMI), total cholesterol (TC) and systolic blood pressure (SBP) are associated with better survival. It is unknown at which time point along the disease continuum the adverse impact of these RF ceases and may 'start to reverse'. We analyzed the distribution of RF and their association with survival across HF stages.

METHODS

We pooled data from four cohort studies from the German Competence Network HF. Employing ACC/AHA-criteria, patients were allocated to stage A (n=218), B (n=1324), C1 (i.e., New York Heart Association [NYHA] classes I & II; n=1134), and C2+D (NYHA III & IV; n=639).

RESULTS

With increasing HF severity median age increased (63/67/67/70 years), whereas the proportion of females (56/52/37/35%), median BMI (26.1/28.8/27.7/26.6 kg/m(2)), TC (212/204/191/172 mg/dl), and SBP (140/148/130/120 mmHg) decreased (P<0.001 for trend for all). In the total cohort, higher levels of all RF were associated with better survival, even after extensive adjustment for multiple confounders. If analyses were stratified, however, a higher RF burden predicted better survival only in clinically symptomatic patients: hazard ratio (HR) per +2 kg/m(2) BMI 0.91 (95% confidence interval 0.88; 0.95); per +10 mg/dl TC 0.93 (0.92; 0.95); per +5 mmHg SBP 0.94 (0.92; 0.95).

CONCLUSION

In this well-characterized sample of patients representing the entire HF continuum, reverse associations were only consistently observed in symptomatic HF stages. Our data indicate that the phenomenon of a "reverse epidemiology" in HF is subject to significant selection bias in less advanced disease.

Body mass index in dementia

This review comprehensively examines the current knowledge on the relationship between body mass index (BMI) and dementia. The association between BMI and cognition is complex: in younger adults, higher BMIs are associated with impaired cognition. Overweight and obesity in middle age are linked to increased future dementia risk in old age. However, when examined in old age, higher BMIs are associated with better cognition and decreased mortality. Little is known about the optimal BMI for well-being and survival in populations already suffering from dementia. Lifetime trends in weight, rather than single measures, might predict prognosis better and help untangle these apparent contradictions. Thus, the need arises to properly monitor BMI trends in affected dementia patients. Registries can include BMI, improving the management of dementia patients throughout the whole course of the disease. The role of central obesity and systemic inflammation on brain pathology and cognitive decline are discussed in this review. Understanding the life-course changes in BMI and their influence on dementia risk, cognitive prognosis and mortality after diagnosis may provide new insights into the underlying pathophysiology of dementia and shape possible intervention and treatment strategies.

Predictors of peritonitis and the impact of peritonitis on clinical outcomes of continuous ambulatory peritoneal dialysis patients in Taiwan--10 years' experience in a single center

OBJECTIVE

Peritoneal dialysis (PD) has become more prevalent as a treatment modality for end-stage renal disease, and peritonitis remains one of its most devastating complications. The aim of the present investigation was to examine the frequency and predictors of peritonitis and the impact of peritonitis on clinical outcomes. ♢

METHODS

Our retrospective observational cohort study enrolled 391 patients who had been treated with continuous ambulatory PD (CAPD) for at least 90 days. Relevant demographic, biochemical, and clinical data were collected for an analysis of CAPD-associated peritonitis, technique failure, drop-out from PD, and patient mortality. ♢

RESULTS

The peritonitis rate was 0.196 episodes per patient-year. Older age (>65 years) was the only identified risk factor associated with peritonitis. A multivariate Cox regression model demonstrated that technique failure occurred more often in patients experiencing peritonitis than in those free of peritonitis (p < 0.001). Kaplan-Meier analysis revealed that the group experiencing peritonitis tended to survive longer than the group that was peritonitis-free (p = 0.11). After multivariate adjustment, the survival advantage reached significance (hazard ratio: 0.64; 95% confidence interval: 0.46 to 0.89; p = 0.006). Compared with the peritonitis-free group, the group experiencing peritonitis also had more drop-out from PD (p = 0.03). ♢

CONCLUSIONS

The peritonitis rate was relatively low in the present investigation. Elderly patients were at higher risk of peritonitis episodes. Peritonitis independently predicted technique failure, in agreement with other reports. However, contrary to previous studies, all-cause mortality was better in patients experiencing peritonitis than in those free of peritonitis. The underlying mechanisms of this presumptive "peritonitis paradox" remain to be clarified.

Obesity in patients undergoing dialysis and kidney transplantation

Obesity poses a major challenge for nephrologists and patients alike, and its prevalence among patients with kidney disease is increasing at least as fast as in the general population. Although the body mass index (BMI) is the most commonly used measurement of excess adiposity, it has important limitations that can be ameliorated by incorporating other markers of body composition. The influence of obesity on outcomes in patients undergoing dialysis and kidney transplantation is of great interest. Although the preponderance of epidemiologic data suggests that, at least in patients undergoing dialysis, obesity has a neutral or protective effect on mortality, although this has not been confirmed in interventional studies needed to establish causality. The effect of obesity on other important outcomes such as quality of life has yet to be determined, and much less information on obesity and outcomes is available in the kidney transplantation population. Similarly, research on the optimal strategies and effects of weight loss in dialysis and kidney transplantation patients is at a nascent stage.

Association of dyslipidemia with renal outcomes in chronic kidney disease

Dyslipidemia is highly prevalent in patients with chronic kidney disease (CKD) and the relationship between dyslipidemia with renal outcomes in patients with moderate to advanced CKD remains controversial. Hence, our objective is to determine whether dyslipidemia is independently associated with rapid renal progression and progression to renal replacement therapy (RRT) in CKD patients. The study analyzed the association between lipid profile, RRT, and rapid renal progression (estimated glomerular filtration rate [eGFR] slope <-6 ml/min/1.73 m(2)/yr) in 3303 patients with stages 3 to 5 CKD. During a median 2.8-year follow-up, 1080 (32.3%) participants commenced RRT and 841 (25.5%) had rapid renal progression. In the adjusted models, the lowest quintile (hazard ratios [HR], 1.23; 95% confidence interval [CI], 1.01 to 1.49) and the highest two quintiles of total cholesterol (HR, 1.25; 95% CI, 1.02 to 1.52 and HR, 1.35; 95% CI, 1.11 to 1.65 respectively) increased risks for RRT (vs. quintile 2). Besides, the highest quintile of total cholesterol was independently associated with rapid renal progression (odds ratio, 1.36; 95% CI, 1.01 to 1.83). Our study demonstrated that certain levels of dyslipidemia were independently associated with RRT and rapid renal progression in CKD stage 3-5. Assessment of lipid profile may help identify high risk groups with adverse renal outcomes.

Increasing prevalence of peripheral artery occlusive disease in hemodialysis patients: a 2-year follow-up

INTRODUCTION

Peripheral artery occlusive disease (PAOD) has been reported to be prevalent in hemodialysis patients and influence their mortality. Ankle-brachial index (ABI) <0.9 is a reliable marker for PAOD. The aims of the 2-year longitudinal study were to assess whether there was a progression in PAOD and to find out the determinants of ABI progression in hemodialysis patients.

METHODS

This study enrolled 237 routine hemodialysis patients and 154 patients completed the 2-year follow-up. The ABI was measured by an ABI-form device at baseline and at the first and second year follow-up. The change in ABI (ΔABI) was defined as ABI measured at the second year follow-up minus ABI measured at baseline.

RESULTS

The prevalence of ABI <0.9 increased yearly (10.4%, 22.7% and 27.9%, respectively; P < 0.001) and the values of ABI decreased yearly (1.11 ± 0.16, 0.97 ± 0.17 and 0.96 ± 0.19, respectively; P < 0.001) in the 154 follow-up patients. Multiple stepwise analysis identified fasting glucose level, calcium-phosphorous product, high-sensitivity C-reactive protein and homocysteine level as independent determinants of ΔABI.

CONCLUSIONS

Our results demonstrated the prevalence of PAOD increased and the values of ABI decreased yearly in hemodialysis patients. The ABI progression was associated with high fasting glucose level, high calcium-phosphorous product, high-sensitivity C-reactive protein and low homocysteine levels.

Reverse epidemiology of hypertension-mortality associations in hemodialysis patients: a long-term population-based study

BACKGROUND

Although hypertension (HTN) is a predictor of mortality, recent data have questioned the link between baseline HTN and mortality in incident hemodialysis (HD) patients. We used Taiwan's National Health Insurance claim data (NHRI-NHIRD-99182) to investigate the association.

METHODS

In 1999, this longitudinal cohort study enrolled 5752 new HD patients. Follow-up began from the initiation of HD until death, the end of HD, or the end of 2008. A Kaplan-Meier survival analysis was done. Cox proportional hazard analysis was used to identify the risk factors for mortality.

RESULTS

The prevalence of baseline HTN was 75.47%. Patients with HTN had a higher prevalence of diabetic mellitus (DM) and cardiovascular diseases. The 1-, 5-, and 9-year cumulative survival rates were 95.5, 63.7 and 41.8% in patients with HTN, and 95.5, 71.0, and 52.0% in those without HTN (log-rank test: P <0.001). Multivariate analysis showed that patients with baseline HTN may have a higher survival rate (hazard ratio (HR) 0.901, 95% confidence interval (CI): 0.819-0.992). After stratification by age and DM, only elderly (≥65) patients without DM had a significantly higher survival rate (HR 0.769, 95% CI: 0.637-0.927). HTN predicts lower mortality with increasing age in patients with congestive heart failure (CHF) or coronary artery disease (CAD).

CONCLUSIONS

There is a reverse (counterintuitive) association between baseline HTN and mortality in elderly HD patients without DM and a clear tendency for a reverse association with increasing age in patients with CHF or CAD. Further study of the association between HTN and mortality in older HD patients may be warranted.

Asymmetric dimethylarginine: a novel cardiovascular risk factor in end-stage renal disease

OBJECTIVE

This cross-sectional study explored the association between carotid intima-media thickness (CIMT) and the oxidative stress markers asymmetric dimethylarginine (ADMA) and homo cysteine in patients with end-stage renal disease who were on haemodialysis.

METHODS

A total of 30 patients undergoing chronic haemodialysis treatment were recruited to this study. Homocysteine and ADMA levels were determined using a fluorescence polarization immunoassay and an enzyme-linked immunosorbent assay, respectively. CIMT was measured as a marker of atherosclerosis using high-resolution ultrasonography and was performed after haemodialysis.

RESULTS

Significant positive correlations were found between CIMT and ADMA, and CIMT and duration of haemodialysis. Linear regression analysis showed that ADMA level and age were significant independent determinants of CIMT, whereas homo cysteine was not.

CONCLUSIONS

The relationship demonstrated between plasma ADMA and carotid artery thickening suggests that ADMA may be a novel marker of atherosclerosis in patients on haemodialysis.

Long-term survival and predictors for mortality among dialysis patients in an endemic area for chronic liver disease: a national cohort study in Taiwan

Background

Patients with end-stage renal disease (ESRD) are at a higher risk for chronic hepatitis, liver cirrhosis (LC) and mortality than the general population. Optimal modalities of renal replacement therapy for ESRD patients with concomitant end-stage liver disease remain controversial. We investigated the long-term outcome for chronic liver disease among dialysis patients in an endemic area.

Methods

Using Taiwan’s National Health Insurance claim data (NHRI-NHIRD-99182), We performed a longitudinal cohort study to investigate the impact of comorbidities on mortality in dialysis patients. We followed up 11293 incident hemodialysis (HD) and 761 peritoneal dialysis (PD) patients from the start of dialysis until the date of death or the end of database period (December 31, 2008). A Cox proportional hazards model was used to identify the risk factors for all-cause mortality.

Results

Patients receiving PD tended to be younger and less likely to have comorbidities than those receiving HD. At the beginning of dialysis, a high prevalence rate (6.16 %) of LC was found. Other than well-known risk factors, LC (hazard ratio [HR] 1.473, 95 % CI: 1.329-1.634) and dementia (HR 1.376, 95 % CI: 1.083-1.750) were also independent predictors of mortality. Hypertension and mortality were inversely associated. Dialysis modality and three individual comorbidities (diabetes mellitus, chronic lung disease, and dementia) interacted significantly on mortality risk.

Conclusions

LC is an important predictor of mortality; however, the effect on mortality was not different between HD and PD patients.

Significant correlation between left ventricular systolic and diastolic dysfunction and decreased glomerular filtration rate

Cardiac dysfunction portends a poor prognosis in renal failure and vice versa. Functional abnormalities of heart in patients with renal insufficiency were frequently noted. The aim of this study is to assess the relationship between left ventricular systolic and diastolic function and renal function in patients with various degrees of renal function. This cross-sectional study included 167 patients from our Outpatient Department of Internal Medicine. Left ventricular systolic and diastolic functions were assessed by echocardiography. Clinical and echocardiographic parameters were compared and analyzed. The prevalence of left ventricular ejection fraction (LVEF) <50% was 31.7% and the average value of the ratio of peak early transmitral filling wave velocity (E) to early diastolic velocity of lateral mitral annulus (Ea) was 11.4 ± 6.2. After the multivariate analysis, low systolic blood pressure, rapid heart rate, low albumin, and low estimated glomerular filtration rate (eGFR) (odds ratio = 0.957; 95% confidence interval = 0.929-0.986; p = 0.004) levels were associated with LVEF < 50%. Besides, old age, low albumin, low eGFR (β = -0.172; p = 0.043), and high uric acid levels were associated with high E/Ea. Our findings show a significant correlation between LVEF < 50% and high E/Ea and decreased eGFR.

Stepwise increases in left ventricular mass index and decreases in left ventricular ejection fraction correspond with the stages of chronic kidney disease in diabetes patients

AIMS

Patients with diabetic nephropathy are reported to have a high prevalence of left ventricular structural and functional abnormalities. This study was designed to assess the determinants of left ventricular mass index (LVMI) and left ventricular ejection fraction (LVEF) in diabetic patients at various stages of chronic kidney disease (CKD).

METHODS

This cross-sectional study enrolled 285 diabetic patients with CKD stages 3 to 5 from our outpatient department of internal medicine. Clinical and echocardiographic parameters were compared and analyzed.

RESULTS

We found a significant stepwise increase in LVMI (P < 0.001), LVH (P < 0.001), and LVEF <55% (P = 0.013) and a stepwise decrease in LVEF (P = 0.038) corresponding to advance in CKD stages.

CONCLUSIONS

Our findings suggest that increases in LVMI and decreases in LVEF coincide with advances in CKD stages in patients with diabetes.

Echocardiographic parameters are independently associated with increased cardiovascular events in patients with chronic kidney disease

BACKGROUND

Patients with chronic kidney disease (CKD) are associated with increased cardiovascular (CV) morbidity and mortality. Echocardiographic measures of heart structure and function have been reported to predict adverse CV outcomes in various pathologic conditions. The aim of this study is to assess whether echocardiographic parameters are independently associated with increased CV events in patients with CKD Stages 3-5.

METHODS

We consecutively enrolled 505 CKD patients from our outpatient department of internal medicine. CV events were defined as CV death, hospitalization for unstable angina, non-fatal myocardial infarction, sustained ventricular arrhythmia, hospitalization for congestive heart failure, transient ischemia attack and stroke. The relative CV events' risk was analyzed by Cox regression methods.

RESULTS

In the multivariate analysis, old age, the presence of diabetes, coronary artery disease and atrial fibrillation; decreased serum albumin and hematocrit levels; left atrial diameter (LAD) >4.7 cm [hazard ratio (HR), 2.141; 95% confidence interval (CI), 1.155-3.971, P = 0.016]; increased left ventricular mass index (LVMI) (HR, 1.006; 95% CI, 1.002 to 1.010, P = 0.003) and left ventricular ejection fraction (LVEF) <55% (HR, 2.007; 95% CI, 1.007-3.743, P = 0.028) were independently associated with increased CV events.

CONCLUSIONS

Our findings show that LAD >4.7 cm, increased LVMI and LVEF <55% are independently associated with adverse CV outcomes in CKD patients. Screening CKD patients by means of echocardiography may help identify a high-risk group of poor CV prognosis.

Impaired left ventricular systolic function and increased brachial-ankle pulse-wave velocity are independently associated with rapid renal function progression

Heart failure and increased arterial stiffness are associated with declining renal function. Few studies have evaluated the association between left ventricular ejection fraction (LVEF) and brachial-ankle pulse-wave velocity (baPWV) and renal function progression. The aim of this study was to assess whether LVEF<40% and baPWV are associated with a decline in the estimated glomerular filtration rate (eGFR) and the progression to a renal end point of ≥25% decline in eGFR. This longitudinal study included 167 patients. The baPWV was measured with an ankle-brachial index-form device. The change in renal function was estimated by eGFR slope. The renal end point was defined as ≥25% decline in eGFR. Clinical and echocardiographic parameters were compared and analyzed. After a multivariate analysis, serum hematocrit was positively associated with eGFR slope, and diabetes mellitus, baPWV (P=0.031) and LVEF<40% (P=0.001) were negatively associated with eGFR slope. Forty patients reached the renal end point. Multivariate, forward Cox regression analysis found that lower serum albumin and hematocrit levels, higher triglyceride levels, higher baPWV (P=0.039) and LVEF<40% (P<0.001) were independently associated with progression to the renal end point. Our results show that LVEF<40% and increased baPWV are independently associated with renal function decline and progression to the renal end point.

Decreased high-density lipoprotein cholesterol is associated with inflammation and insulin resistance in non-diabetic haemodialysis patients

AIM

Lower serum high-density lipoprotein cholesterol (HDL-C) is associated with inflammation, insulin resistance and poor cardiovascular outcomes in the general population. However, in a large-scale study, the association between HDL and survival in haemodialysis patients was not present. The exact cause of lack of HDL-C protection in the dialysis population is still obscure.

METHODS

A total of 89 stable non-diabetic haemodialysis patients were recruited. Fasting serum biochemical parameters, complete blood counts and inflammatory markers were obtained before the mid-week dialysis. Insulin resistance was assessed by the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR).

RESULTS

The mean age was 58.2±13.1 years, 37 (41.6%) patients were male. The mean HDL-C level was 56.3±17.1 mg/dL. By bivariate correlation analysis, a lower serum HDL-C level was related to higher body mass index (r=-0.425; P<0.001), higher triglyceride (r=-0.479; P<0.001) and higher HOMA-IR (r=-0.211; P<0.05) levels. The serum HDL-C level was also inversely related to high-sensitivity C-reactive protein (hsCRP) (r=-0.297; P=0.005) and tumour necrosis factor-α (TNF-α) (r=-0.295; P=0.005) and directly correlated with adiponectin (r=0.560; P<0.001). In multivariate linear regression analysis, HDL-C was found to be directly correlated with adiponectin (β-coefficient=0.569; P<0.001) and inversely correlated with TNF-α (β-coefficient=-0.292; P=0.001).

CONCLUSION

A strong association between HDL-C, inflammatory surrogates, and insulin resistance in this non-diabetic, non-obese haemodialysis patient group is demonstrated. The HDL-C level is still a good parameter to screen high-risk patients.

The diabetic CKD patient--a major cardiovascular challenge

The diabetic patient with chronic kidney disease (CKD) is at very high risk of cardiovascular disease (CVD). Primary and secondary CVD prevention is of major importance and should be targeted at both traditional cardiovascular risk factors and risk factors specific for patients with CKD, such as albuminuria, anaemia and CKD--mineral and bone disorder. However, treatment goals have largely been derived from clinical trials including patients with no or only mild CKD and may not be generalizable to patients with advanced renal disease. Moreover, in patients on renal replacement therapy, the association between traditional CVD risk factors and the incidence of CVD may be reversed, and pharmaceutical interventions that are beneficial in the general population may be ineffective or even harmful in this high-risk population. Those involved in the delivery of care to patients with diabetes and CKD need to be aware of these issues and should adopt an individualised approach to treatment.

A systolic parameter defined as the ratio of brachial pre-ejection period to brachial ejection time predicts cardiovascular events in patients with chronic kidney disease

BACKGROUND

Patients with chronic kidney disease (CKD) are associated with an increased risk of cardiovascular (CV) events. An increase in the ratio of the pre-ejection period (PEP) to ejection time (ET) is correlated with a decrease of left ventricular systolic function. Brachial PEP (bPEP) and brachial ET (bET) can be automatically determined from an ankle-brachial index (ABI)-form device. The aim of this study is to investigate whether bPEP/bET is a useful predictor for CV events in patients with CKD.

METHODS AND RESULTS

We consecutively enrolled 242 CKD patients from our outpatient department of internal medicine. The bPEP and bET were measured using an ABI-form device. CV events were defined as cardiac death, stroke, myocardial infarction, and hospitalization for congestive heart failure. The study subjects were followed until the first episode of CV events occurred. The relative CV event risk was analyzed by Cox-regression methods. In the multivariate analysis, the presence of diabetes (hazard ratio (HR), 3.531; P=0.014), increased bPEP/bET (HR, 1.054; P=0.026), and decreased serum albumin level (HR, 0.525; P=0.005) were independent predictors for CV events.

CONCLUSIONS

The study findings show that bPEP/bET is a useful predictor of CV events in CKD patients. Screening CKD patients by means of bPEP/bET might help to identify patients at high risk of increased CV events. 

Predicting cardiovascular disease morbidity and mortality in chronic kidney disease in Spain. The rationale and design of NEFRONA: a prospective, multicenter, observational cohort study

Background

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in patients with chronic kidney disease (CKD). Cardiovascular risk assessment in this population is hampered by the failure of traditional risk factors to fully account for the elevated CVD risk (reverse epidemiology effect) and the presence of emerging risk factors specifically related to kidney failure. Therefore, diagnostic tools capable of improving cardiovascular risk assessment beyond traditional risk factors are currently warranted. We present the protocol of a 4-year prospective study aimed to assess the predictive value of non-invasive imaging techniques and biomarkers for CVD events and mortality in patients with CKD.

Methods

From November 2009 to October 2010, 4137 asymptomatic adult patients with stages 2 to 5 CKD will be recruited from nephrology services and dialysis units throughout Spain. During the same period, 843 participants without CKD (control group) will be recruited from lists of primary care physicians, only at baseline. During the follow-up, CVD events and mortality will be recorded from all CKD patients. Clinical and laboratory characteristics will be collected in a medical documentation sheet. Three trained itinerant teams will carry out a carotid ultrasound to assess intima-media thickness and presence of plaques. A composite atherosclerosis score will be constructed based on carotid ultrasound data and measurement of ankle-brachial index. In CKD patients, presence and type of calcifications will be assessed in the wall of carotid, femoral and brachial arteries, and in cardiac valves, by ultrasound. From all participants, blood samples will be collected and stored in a biobank to study novel biomarkers.

Conclusions

The NEFRONA study is the first large, prospective study to examine the predictive value of several non-invasive imaging techniques and novel biomarkers in CKD patients throughout Spain. Hereby, we present the protocol of this study aimed to explore the most effective way in which these tests can be integrated with traditional risk factors to maximize CVD detection in this population.