Usefulness of clinical evaluation, troponins, and C-reactive protein in predicting mortality among stable hemodialysis patients

Assessment of Malnutrition Inflammation Score in Different Stages of Chronic Kidney Disease

BACKGROUND

Protein-energy wasting (PEW) is common in patients with chronic kidney disease (CKD), and is associated with high morbidity and mortality. Malnutrition-Inflammation Score (MIS) has significant correlations with prospective hospitalization and mortality, as well as measures of anemia, inflammation, and nutrition in dialysis patients.

MATERIAL AND METHODS

The study was conducted on 100 adult patients of CKD selected from K&D clinic PGIMS, Rohtak. All the patients went under detailed socioeconomic, clinical, biochemical and radiological examination. The average of three measurements of body weight, height, triceps skin fold thickness (TST), and mid-arm muscle circumference (MAMC) were measured in all patients. MIS was calculated for all the patients.

RESULTS

Out of total 100 patients, 64 were male and 36 were female. Overall, the prevalence of malnutrition was 60%. A total of 42%, 16% and 2% patients had mild, moderate and severe malnutrition respectively. Our study also shows significant association between staging of CKD (3 to 5-D) and MIS. A significant negative correlation was found between MIS and factors such as BMI, eGFR, serum calcium and hemoglobin levels. A significant positive correlation of this score was found with blood urea serum creatinine, serum uric acid, serum potassium and serum phosphate. Multivariate analysis showed significant association between MIS and serum albumin, TIBC, BMI, family income and hs-CRP.

CONCLUSION

Assessment of key components of malnutrition and inflammation early in disease course will help to identify high risk subjects in whom modifying these predictors will help in providing active and healthy life for CKD patients.

Ankle-brachial index, arterial stiffness, and biomarkers in the prediction of mortality and outcomes in patients with end-stage kidney disease

BACKGROUND

Although ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV) are significant predictors of major adverse cardiovascular event (MACE), their prognostic value in association with biomarkers has not been fully evaluated in patients with end-stage kidney disease (ESKD).

HYPOTHESIS

We hypothesized that ABI/baPWV would provide better prognostic value independent of biomarkers in ESKD patients.

METHODS

This study included 104 ESKD patients treated with maintenance hemodialysis who underwent ABI and baPWV examinations and laboratory tests, including brain-natriuretic peptide, high-sensitive cardiac troponin T (hs-cTnT), and high-sensitive C-reactive protein (hs-CRP). MACE was defined as a composite event of all-cause death, acute coronary syndrome, and stroke.

RESULTS

During a mean follow-up of 3.6 ± 1.7 years, a total of 51 MACE were observed. The independent factors associated with MACE were age >75 years (adjusted hazard ratio [HR], 2.15; P < .05), abnormal ABI (adjusted HR, 2.01; P < .05), left ventricular ejection fraction (LVEF) <50% (adjusted HR, 3.33; P < .001), the upper tertile of hs-cTnT (adjusted HR, 2.77; P < .05), and hs-CRP (HR, 1.96; P < .05). However, baPWV did not remain as an independent predictor of MACE in the entire cohort and also in patients without abnormal ABI. The combination of predictors improves the predictive value of MACE, providing increased HR with 4.00 for abnormal ABI + hs-CRP, 4.42 for abnormal ABI + hs-cTnT, and 7.04 for abnormal ABI + LVEF <50% (all P < .001).

CONCLUSION

Abnormal ABI is a robust predictor of MACE independent of biomarkers and their combination provides better risk stratification compared with a single predictor in ESKD patients.

Coronary Angiography Profile at the Time of Hemodialysis Initiation in End-Stage Renal Disease Population: A Retrospective Analysis

Cardiovascular disease is associated with increased mortality in dialysis population. However, there are very few studies that assessed the prevalence of coronary artery disease (CAD) at the time of initiation of hemodialysis (HD). The present study was aimed to assess the prevalence of CAD in end-stage renal disease (ESRD) patients at the time of initiation of HD and the risk factors for CAD in this population. This was a single-center retrospective study and included ESRD patients who underwent coronary angiography (CAG) at the time of initiation of HD. Inclusion criteria were age >18 years and those who were subjected to CAG within 2 weeks of initiation of HD. According to the findings on CAG, patients were divided into no CAD and CAD groups. CAD was diagnosed if there was >50% stenosis of vessel. Clinical and laboratory parameters between these two groups were analyzed. Ninety-seven patients were included in the study based on the inclusion criteria. Forty-four (45%) patients were diagnosed with CAD. Patients who had CAD were younger compared to no CAD group (50.7 + 10 vs. 55.8 + 9.3 years; P = 0.01). Majority of them were males. Diabetic nephropathy (DN) was associated with increased risk of CAD (60% vs. 40%, P = 0.007). History of smoking, high high-sensitivity C-reactive protein (hs-CRP), low total cholesterol, and low high-density lipoprotein (HDL) were associated with significantly increased risk of CAD. Gender, symptoms of CAD, serum low-density lipoprotein (LDL), very LDL, and triglycerides were not associated with increased risk of CAD. Neither calcium (Ca), phosphorus (PO₄), nor Ca × PO₄products were associated with an increased risk of CAD. Resting electrocardiogram abnormalities had no significance in predicting CAD (32% in CAD and 19% in no CAD group). Echocardiography showed regional wall motion abnormalities/global hypokinesia in 18% patients of CAD group and 3.8% patients of no CAD group (P = 0.03). Single-, double-, and triple-vessel disease was documented in 17 (38%), 13 (29.5%), and 14 (32.5%) patients, respectively, and the most common vessel involved was the left anterior descending artery. At the initiation of HD in ESRD patients, CAD was seen in almost half of the patients. DN was a significant risk factor for CAD. Other risk factors for CAD include smoking, low cholesterol, low HDL, and high hs-CRP levels.

Impact of Malnutrition, Inflammation, and Atherosclerosis on the Outcome in Hemodialysis Patients

Malnutrition, inflammation, and atherosclerosis are significant problems in patients on hemodialysis. A prospective, observational study in 100 hemodialysis patients for 2 years was conducted. The primary outcomes were hospitalizations and mortality at the end of 2 years. The mean age was 61 ± 11.3 years and 69% were male. Seven patients did not complete the study (five underwent transplant and two were shifted to other units). Serum albumin was significantly lower in malnourished patients at 6 months from the beginning of the study period (3.58 vs. 3.79 g/dl, P = 0.001). Malnutrition based on subjective global assessment (SGA) was seen in 30 (32%) patients: mild to moderate in 27 (29%) and severe in 3 (3%). Inflammation was seen in 73 (78.5%) patients and intimal-medial thickness of >1.1 mm indicating significant atherosclerosis was seen in 73 (78.5%) patients. Modified SGA score and malnutrition-inflammation score (MIS) were significantly more in the malnourished group. Statistically significant association was seen between hospitalization and mortality in the malnourished population, and the odds ratio of death in malnourished patients was 9.83 (95% confidence interval: 2.8-34.3, P < 0.001). There was a moderate correlation between malnutrition assessed by modified SGA and MIS score (r = 0.54, P < 0.001). Mortality rate was 37% in patients with mild to moderate and 67% in severe malnutrition. Hospital admission was seen in 43 (46%) patients and was significantly more common in malnourished compared to well-nourished patients (77% vs. 32%, P < 0.001). Multiple logistic regression analysis showed that malnutrition by Modified SGA was the only significant variable associated with mortality at 2 years, and addition of MIS score did not improve the predictive ability of the model to modified SGA. We recommend the use of modified SGA and serial serum albumin to monitor nutrition in hemodialysis patients.

Minor Elevation in C-Reactive Protein Levels Predicts Incidence of Erythropoiesis-Stimulating Agent Hyporesponsiveness among Hemodialysis Patients

BACKGROUND

Hemodialysis (HD) patients occasionally experience minor asymptomatic elevation in C-reactive protein (CRP) levels, which may be associated with difficulty in managing renal anemia using erythropoiesis-stimulating agents (ESAs). Here, we assessed whether elevation of CRP predicts future incidences of ESA hyporesponsiveness.

METHODS

A total of 2,956 HD patients lacking ESA hyporesponsiveness and infectious diseases were enrolled, and the association between CRP levels and incidence of ESA hyporesponsiveness was assessed. CRP levels were divided into 4 categories (normal [<1.0 mg/l], mild [1.0 ≤ CRP <3.0 mg/l], moderate [3.0 ≤ CRP <10.0 mg/l] and high [≥ 10.0 mg/l]). The primary outcome was the cumulative incidence of ESA hyporesponsiveness, defined as a failure to achieve hemoglobin level ≥ 10 g/dl despite receiving high doses of ESAs (≥ 9,000 U/week recombinant human epoetin [rHuEPO]-α or rHuEPO-β and ≥ 60 μg/week darbepoetin-α) during 12 months of follow-up.

RESULTS

The cumulative incidence of ESA hyporesponsiveness was 134 (4.8%) occurrences over 4 months and 300 (12.4%) over 12 months. The elevated CRP groups had significantly higher incidence of ESA hyporesponsiveness over 4 months of follow-up than the normal reference group (adjusted relative risk [RR] 1.6, 95% CI 1.0-2.6 for moderate; adjusted RR 2.5, 95% CI 1.5-4.1 for high). Furthermore, the association remained consistent even over 12 months (adjusted RR 1.4, 95% CI 1.0-1.8 for moderate; adjusted RR 1.6, 95% CI 1.1-2.4 for high).

CONCLUSIONS

Elevated CRP levels were associated with future incidence of ESA hyporesponsiveness from low-grade inflammation (3.0 ≤ CRP <10.0 mg/l).

Cardiovascular biomarkers in chronic kidney disease: state of current research and clinical applicability

The high incidence of cardiovascular events in chronic kidney disease (CKD) warrants an accurate evaluation of risk aimed at reducing the burden of disease and its consequences. The use of biomarkers to identify patients at high risk has been in use in the general population for several decades and has received mixed reactions in the medical community. Some practitioners have become staunch supporters and users while others doubt the utility of biomarkers and rarely measure them. In CKD patients numerous markers similar to those used in the general population and others more specific to the uremic population have emerged; however their utility for routine clinical application remains to be fully elucidated. The reproducibility and standardization of the serum assays are serious limitations to the broad implementation of these tests. The lack of focused research and validation in randomized trials rather than ad hoc measurement of multiple serum markers in observational studies is also cause for concern related to the clinical applicability of these markers. We review the current literature on biomarkers that may have a relevant role in field of nephrology.

Clinical usefulness of novel prognostic biomarkers in patients on hemodialysis

Prognosis, risk stratification and monitoring the effects of treatment are fundamental elements in the decision-making process when implementing prevention strategies for chronic kidney disease. The use of biomarkers is increasingly proposed as a method to refine risk stratification and guide therapy. In this Review, we present basic concepts regarding the validation of biomarkers and highlight difficulties inherent to the identification of useful new biomarkers in patients on hemodialysis. We focus on prognostic biomarkers that have been consistently linked to survival in this group of patients. To date, no biomarker has had sufficient full-scale testing to qualify as a useful addition to standard prognostic factors or to guide the prescription of specific treatments in this population. Furthermore, little information exists on the relative strength of various biomarkers for their prediction of mortality. A multimarker approach might refine prognosis in patients on hemodialysis, but this concept needs to be properly evaluated in large longitudinal studies and clinical trials. The potential of proteomics for the identification and study of new biomarkers in the pathophysiology of cardiovascular disease in patients with end-stage renal disease is also discussed.

Predictors of cardiovascular events after liver transplantation: a role for pretransplant serum troponin levels

Cardiovascular complications are major causes of morbidity and mortality after liver transplantation. Identifying candidates at highest risk of postoperative complications is a cornerstone of optimizing outcomes and utility. Using traditional cardiac risk factors in addition to C-reactive protein (CRP) levels, troponin levels, and echocardiographic parameters before transplantation, we sought to define cardiac risk so that we could predict cardiovascular events after transplantation. From December 1998 to December 2001, 230 adult patients who underwent liver transplantation with a median follow-up of 8.2 years were studied. The risk factors for cardiac disease were as follows: male gender with a mean age of approximately 50 years (57%), smoking history (60%), diabetes (23%), hypertension (19%), elevated troponin (25%), elevated CRP (25%), and preexisting cardiac disease (16%). Fifty-nine cardiac events occurred over 8.2 years. Risk factors (univariate analysis) for first cardiac events included age in decades [hazard ratio (HR) = 1.31, P = 0.047], diabetes (HR = 2.20, P = 0.004), prior cardiovascular disease (HR = 4.77, P < 0.0001), a troponin I level > 0.07 ng/mL (HR = 2.00, P = 0.023), left ventricular hypertrophy (HR = 2.06, P = 0.047), stress wall abnormalities (HR = 2.25, P = 0.018), and ischemia on stress imaging (HR = 2.89, P = 0.015). Multivariate analysis confirmed age, diabetes, a troponin I level > 0.07, and prior cardiac disease as independent risk factors for posttransplant cardiac events. In conclusion, pretransplant elevated troponin levels, diabetes, and a history of cardiovascular disease, alone or in combination, are strongly associated with the occurrence of posttransplant cardiovascular events.

Effect of hemodialysis on traditional and innovative cardiac markers

The diagnostic approach to acute coronary syndrome (ACS) is challenging in patients with impaired renal function since most serum biomarkers are commonly increased in this clinical setting. Cardiac troponin T (cTnT), creatine kinase isoenzyme MB (CK MB), myoglobin, and ischemia modified albumin (IMA), were assayed in 45 patients prehemodialysis (pre-HD) and posthemodialysis (post-HD), and results were adjusted for hemoconcentration. The pre-HD values of serum IMA and cTnT were above the respective diagnostic thresholds (IMA<85 K units/L; cTnT <0.03 ng/mL) in six (13%) and 27 (60%) patients undergoing chronic HD, respectively. A significant (105.0 vs. 79.0 K units/L, P<0.0001) and variable (+38%; 95% confidence interval [CI], 12-65%) increase of serum IMA was observed post-HD, whereas the other biomarkers significantly decreased (cTnT: 0.029 vs. 0.044 ng/mL, P=0.016; CK-MB: 2.33 vs. 2.50 microg/L, P<0.0001; myoglobin: 128.1 vs. 148.7 microg/L, P<0.0001). Biomarkers of myocardial injury, especially cTnT and IMA, might be used in HD patients, provided that an appropriate diagnostic interpretation is guarantee, according to individual baseine value, metabolism, and time of sampling. Moreover, IMA might be reliably applied to stratify the long-term risk of these patients, but not for diagnosing an ACS during or immediately post-HD.

Relationships of N-terminal pro-B-natriuretic peptide and cardiac troponin T to left ventricular mass and function and mortality in asymptomatic hemodialysis patients

BACKGROUND

Although the cardiac biomarker troponin T (cTnT) is related strongly to mortality in patients with end-stage renal disease, the independent association of N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) and cTnT levels in predicting outcomes is unknown. The objective of this study is to determine factors associated with NT-pro-BNP and cTnT and determine whether these levels are associated with mortality.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

Asymptomatic hemodialysis patients (n = 150) in 4 university-affiliated hemodialysis units. EXPOSURE & OUTCOMES: For cross-sectional analysis, echocardiographic variables as exposures and NT-pro-BNP and cTnT levels as outcomes; for longitudinal analysis, association of NT-pro-BNP and cTnT levels as exposures to all-cause and cardiovascular disease mortality as outcomes.

RESULTS

In a multivariate regression analysis, low midwall fractional shortening, a measure of poor systolic function, was an independent correlate of log NT-pro-BNP level (P < 0.01), whereas left ventricular mass index was an independent correlate of cTnT level (P < 0.01). During a median follow-up of 24 months, 46 patients died, 26 of cardiovascular causes. NT-pro-BNP levels had a strong graded relationship with all-cause (hazard ratios [HRs], 1.54, 4.78, and 4.03 for increasing quartiles; P < 0.001) and cardiovascular mortality (HRs, 2.99, 10.95, and 8.54; P < 0.01), whereas cTnT level had a weaker relationship with all-cause (HRs, 1.57, 2.32, and 3.39; P < 0.01) and cardiovascular mortality (HRs, 0.81, 2.12, and 2.14; P = 0.1). The combination of the 2 biomarker levels did not improve the association with all-cause or cardiovascular mortality compared with NT-pro-BNP level alone. NT-pro-BNP level was a marker of mortality even after adjusting for left ventricular mass index and midwall fractional shortening.

LIMITATIONS

Our cohort was predominantly black and of limited sample size.

CONCLUSION

NT-pro-BNP level strongly correlates with left ventricular systolic dysfunction and is associated more strongly with mortality than cTnT level in asymptomatic hemodialysis patients.