Saudi Journal of Kidney Diseases and Transplantation

ORIGINAL ARTICLE
Year
: 2009  |  Volume : 20  |  Issue : 5  |  Page : 789--793

C- Reactive protein, cardiac troponin T and low albumin are predictors of mortality in hemodialysis patients


Nazila Bagheri, Omolbanin Taziki, Kianoosh Falaknazi 
 Taleghani Medical Center (Nephrology and Transplantation Ward), Shahid Beheshti Medical University, Tehran, Iran

Correspondence Address:
Nazila Bagheri
Taleghani Medical Center (Nephrology and Transplantation Ward), Shahid Beheshti Medical University, Tehran
Iran

Abstract

Overall and cardiovascular mortality are significantly higher in hemodialysis patients with elevated C-reactive protein (CRP). The aim of study was to determine whether CRP, low albumin and troponin are markers of overall and cardiovascular mortality in hemodialysis patients. 138 stable hemodialysis patients were divided into 2 groups n= 66 patients with coronary disease equivalent (known coronary or peripheral vascular disease or diabetes mellitus) and n= 72 patients without it. The two groups were then stratified by biomarkers [cardiac troponin T and Albumin and highly sensitive CRP (hs-CRP)] and followed for 30 months. The primary outcome was all causes mortality. Patients with coronary disease equivalents had 3.5 fold greater annual mortality compared to controls (24%% vs 6.9%, P value = 0.005). Elevated troponin T had a further increase in the risk for death while hs-CRP and low albumin were not associated with risk of death In conclusion, circu­lating cardiac troponin-T was associated with poor prognosis especially in hemodialysis patients with coronary risk factors.



How to cite this article:
Bagheri N, Taziki O, Falaknazi K. C- Reactive protein, cardiac troponin T and low albumin are predictors of mortality in hemodialysis patients.Saudi J Kidney Dis Transpl 2009;20:789-793


How to cite this URL:
Bagheri N, Taziki O, Falaknazi K. C- Reactive protein, cardiac troponin T and low albumin are predictors of mortality in hemodialysis patients. Saudi J Kidney Dis Transpl [serial online] 2009 [cited 2020 Aug 7 ];20:789-793
Available from: http://www.sjkdt.org/text.asp?2009/20/5/789/55362


Full Text

 Introduction



Maintenance hemodialysis (HD) patient's ex­hibit increased cardiovascular mortality and vas­cular events account for more than half of deaths in this population. [1]

The stratification of asymptomatic patients with end stage renal disease (ESRD) into higher and lower risk groups would be useful for iden­tifying patients who might benefit from aggre­ssive evaluation and treatment.

Previous studies have suggested that troponins could be a predicative tool in coronary heart di­sease in ESRD. [1],[2] However, troponin levels in the HD patients could be influenced by factors other than ischemic damage such as retention due to lack of excretion or uremic cardiomyo­pathy. [3]

We proposed that dividing stable patients with ESRD on maintenance HD into different clini­cal subsets by presence or absence of known coronary disease equivalent would lead to clearer risk stratification by abnormal cardiac troponin T as well as hs-CRP and albumin.

 Methods



138 hemodialysis patients from three hemo­dialysis centers were evaluated from June 2005 to December 2007.

Demographic and medical data were obtained from patients' interviews, chart reviews and hos­pital information system. Inclusion criteria in­cluded all of patients who were on maintenance HD for > 6 months.

The exclusion criteria included:



Systemic inflammation such as active auto­immune disease, infectious diseasesOngoing ischemia or any revascularization procedure during recent 8 weeks. Informed consent was obtained from all patients.The primary outcome variable was all cause mortality. Mortality data was collected by sear­ching death records, from hospital charts, and through family phone interviews.

Diabetic patients or patients who had periphe­ral vascular disease were classified as patients having potential coronary artery disease. Patients with previous documented myocardial infarction or a history of surgical or percutaneous coro­nary revascularization, were defined as having coronary artery disease.

Peripheral vascular disease was defined as ha­ving any of the following: carotid artery steno­sis of > 50%, abdominal or thoracic aortic aneu­rysm and peripheral arterial disease. Blood sam­ple for hs-CRP and troponin T were measured before the beginning of mid week hemodialysis session for three consecutive months.

Serum troponin T level were measured by elec­trochemiluminescence immune assay and hs­CRP by nephlometry (CV th percentile for reference population being 0.01 mg/L. Laboratory personnel were unaware of patient's clinical data. Following the recommendation of Center for Disease Control and Prevention and the American heart associa­tion [4] the 2 clinical groups (patients with coro­nary disease and those without) were further stratified by hs-CPR values( 3 mg/L) and C-TnT was defined as being 0.05 mg/L and > 0.05 mg/L.

Patients were divided into two groups. Group I: patient who had coronary disease. Group II: with no history of coronary artery disease or risk factors.

Cardiac troponin T and hs-CRP and mortality were compared between two groups.

 Statistical analysis



Clinical variable are reported as mean ± SD and categorical variable as percentages. Fishers exact test was used to compare categorical va­riables, and continuous variables were evalua­ted using unpaired student ' s t test. P 3mg/L) in (n= 32) 23.1% patients. C-TnT was found to be elevated in (40%) (n= 56/138) of patients. C-TnT was higher in Group I compared to Group II 46/66 (69.6%) vs 10/72 (13/8%) (P value = 0.03), [Table 2].

In Group I patients with elevated C-TnT > 0.1 ng/dL had 3.5 fold greater mortality (24.2% vs 6.9%, P= 0.005).

Hs-CRP (> 3 mg/L) evaluated in group I did not add to the mortality risk. Both groups had si­milar high serum levels of hs-CRP (group I: n= 7 vs group II: n= 4, P= 0.24), [Table 2] but mor­tality was higher in patients with high hs-CRP (34% vs 9%) without considering the CAD risk factors.

There was not any significant difference bet­ween serum albumin levels in the two groups.

 Discussion



Serum C-TnT and hs-CRP elevated in hemo­diaysis patients, posses a common clinical prob­lem in patients with ESRD. Several studies have supported that elevation of C-TnT and hs-CRP as predictors of increased mortality. [5],[6],[7],[8]

In our study, we evaluated the clinical risks for coronary artery disease in association with the.

The findings of the present study are compa­tible with previous studies but are unique in se­veral aspects.

We found that large percentage of asympto­matic patients with ESRD have elevations of C­-TnT, compatible with other studies. [5],[6],[9] Our study also confirmed that C-TnT is independent pre­dictor of all cause mortality in these patients further more cTnT alone had better predictive value than C-reactive protein (CRP) alone for mortality and first cardiovascular events. [10]

As it is shown in [Table 1], the age and duration of hemodialysis in group 1 was higher (P [11]

Our studies showed serum albumin and hs­CRP were not significantly different in two groups although pervious studies describe that serum CRP and albumin in ESRD patients are strong predictors for cardiovascular mortality. [12],[13] .This may be due to the small sample size in our patients. The most common cause of mortality in HD patients is cardiovascular diseases (CVD), while the most common cause of co-morbidity is infections [16] which is associated with higher CRP levels compared with cardiac death. [17] .

The CRP levels are highly variable and in­fluenced by intercurrent events in dialysis pa­tients. Use of statins may reduce the CRP levels although these agents are not shown to reduce the cardiovascular mortality in diabetic dialysis patients. [18]

Furthermore, higher levels of cTnT may iden­tify patients with severe angiographic coronary disease. [19]

Our patients in Group I had significant cardiac disease as shown in [Table 1]; prevalence of dys­lipidemia and heart failure was higher in this group.

In addition some studies have not found an association between malnutrition/inflammation and an increased risk of atherosclerosis among dialysis patients [20],[21] which is compatible to some extent with our study also.

In conclusion, C-TnT per se is more helpful in risk stratifying of patients with ESRD and coro­nary disease equivalent. Elevated hs-CRP and low albumin level was not associated with coro­nary artery disease related mortality and may be a better predictor of death due to inflammation and infection in further larger studies in main­tenance HD patients.

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