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| ORIGINAL ARTICLE |
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| Year : 2022 | Volume
: 47
| Issue : 3 | Page : 194-203 |
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Neutrophil–lymphocyte ratio and monocyte–lymphocyte ratio as predictors of cardiovascular risk and mortality in end-stage renal disease
Salma F Rezk1, Lina E Khedr1, Howayda A E El-Shinnawy1, Haitham E Abd El-Aziz1, Amr M Mohamed2, Mohamed Saeed Hassan1
1 Department of Internal Medicine and Nephrology, Ain Shams University, Cairo, Egypt
2 Department of Cardiovascular Medicine, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| Date of Submission | 16-Apr-2022 |
| Date of Acceptance | 19-Apr-2022 |
| Date of Web Publication | 03-Jan-2023 |
Correspondence Address:
Salma F Rezk
Faculty of Medicine, Ain Shams University, Cairo 11528
Egypt
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/ejh.ejh_21_22
Background The neutrophil–lymphocyte ratio (NLR) and monocyte–lymphocyte ratio (MLR) in the peripheral blood are used as indicators of systemic inflammation and predictors of cardiovascular (CV) diseases. Aims To study the relation between both NLR and MLR and the prediction of cardiovascular events (CVE) in end-stage renal disease (ESRD) patients on regular hemodialysis. Patients and methods In all, 70 ESRD patients on regular hemodialysis were followed up for 12 months. NLR, MLR, and their individual components were determined at baseline and in the follow-up months. The changes in NLR and MLR after 12 months were compared. High-sensitivity C-reactive protein and echocardiography studies were done at baseline and after 12 months. Major CVE were recorded. Results Total leukocyte, absolute neutrophil, and monocyte counts were significantly increased over time. The presence of valvular calcification was associated with an increase in both NLR and MLR (P=0.004 and 0.001, respectively) after 12 months. The mean monocyte counts were significantly higher in patients with CV complications. The baseline monocyte count was the best to predict CV complications with a cutoff point more than 0.54 × 103/µl (sensitivity 100%, specificity 73.85%) in the receiver-operating characteristic curve. Conclusion In ESRD patients, leukocyte counts are in a dynamic change. There was no significant change in NLR or MLR over time and their changes could not predict the occurrence of CVE. The monocyte count is an excellent predictor of CV diseases. The presence of valvular calcification is associated with increases in both NLR and MLR over time. Keywords: end-stage renal disease, major cardiovascular events, monocyte count, monocyte-to-lymphocyte ratio, neutrophil-to-lymphocyte ratio
How to cite this article:
Rezk SF, Khedr LE, El-Shinnawy HA, Abd El-Aziz HE, Mohamed AM, Hassan MS. Neutrophil–lymphocyte ratio and monocyte–lymphocyte ratio as predictors of cardiovascular risk and mortality in end-stage renal disease. Egypt J Haematol 2022;47:194-203 |
How to cite this URL:
Rezk SF, Khedr LE, El-Shinnawy HA, Abd El-Aziz HE, Mohamed AM, Hassan MS. Neutrophil–lymphocyte ratio and monocyte–lymphocyte ratio as predictors of cardiovascular risk and mortality in end-stage renal disease. Egypt J Haematol [serial online] 2022 [cited 2023 Mar 30];47:194-203. Available from: http://www.ehj.eg.net/text.asp?2022/47/3/194/366863 |
| Introduction | |  |
Chronic inflammation is a main component in dialysis patients. It is a consequence of multifactorial etiology [1]. In end-stage renal disease (ESRD) patients, markers of systemic inflammation are elevated [2]. There is a high risk of developing cardiovascular (CV) disease [3] and sudden cardiac deaths [4] in ESRD patients. The absolute neutrophil count is a known marker of systemic inflammation, and the lymphocyte count reflects immunosuppression while monocytes contribute mainly to chronic inflammation. The neutrophil-to-lymphocyte ratio (NLR) has been proved as a useful prognostic tool in infectious diseases, inflammatory conditions, and solid tumors [5]. Evidences revealed that NLR or monocyte-to-lymphocyte ratio (MLR) could be used for early prediction of the outcome of CV diseases, including mortality of myocardial infarction [6] and heart failure patients [7]. We studied the relation between changes in both NLR and MLR and the prediction of major cardiovascular events (CVE) in ESRD.
| Patients and methods | | |
Study population
Our prospective cohort study was conducted in our hospital dialysis center between August 2020 and November 2021. It included 70 ESRD patients on regular hemodialysis (HD) from arteriovenous fistula for more than 6 months, who accepted to be enrolled in the study and to be followed up for 12 months. In all, 40 patients were excluded as shown in the flowchart in [Figure 1]. Patients with diabetes, cancer, acute infections, autoimmune disease, on immunosuppressants, or with acute coronary syndrome at enrollment were excluded. The primary endpoints were changes in NLR and MLR. The secondary endpoints were incidences of major CVE. A detailed history taking was done. Physical examination included measurements of BMI, average of systolic and diastolic blood pressures in three different visits, and calculating pulse pressure by subtracting the diastolic blood pressure from the systolic blood pressure. The Ethics Committee of our institution approved the research. The study followed Helsinki Declaration concepts. Informed consents were obtained from all the participants. | Figure 1: Flowchart of the study design. ESRD, end-stage renal disease; EF, ejection fraction; NLR, neutrophil-to-lymphocyte ratio; MLR, monocyte-to-lymphocyte ratio.
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Hemodialysis treatment
All were receiving 12 h HD per week through arteriovenous fistulae using polysulfone hollow fiber dialyzers with a surface area of 1.4–2.2 m2. Blood flows of 250–300 ml/min and dialysate flows at 500–800 ml/min were applied. Ultrafiltration volume was adapted individually.
Biochemical analyses
Blood samples for albumin, calcium, phosphorus, parathyroid hormone, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides were withdrawn from the arterial site of the arteriovenous fistula at the beginning of HD session. High-sensitivity C-reactive protein (hs-CRP) was withdrawn at the beginning and after 12 months.
Complete blood pictures were withdrawn at baseline, after 3 months, after 6 months, after 9 months, and after 12 months. NLR was calculated as the ratio of absolute neutrophil to absolute lymphocyte counts and MLR as the ratio of absolute monocyte to absolute lymphocyte counts.
Echocardiographic studies
Combined M-mode and two-dimensional studies were performed in all patients at the beginning of the study and after 12 months. They were examined in the left lateral decubitus position. All measurements were made according to the American Society of Echocardiography (ASE) guidelines by the leading edge to the leading edge technique [ejection fraction, left ventricular end diastolic diameter (LVEDD), thickness of the interventricular septum, posterior left ventricular wall end diastolic diameter], and averaged to the closest 1 mm from three good quality cardiac cycles. The left ventricular mass (LVM) was calculated by using: Devereux’s and Reichek formula: 0.8(1.04(LVEDD+interventricular septum diameter+posterior left ventricular wall end diastolic diameter)3−LVEDD3)+0.6 g and normalized to BSA (g/m2) to obtain LVM index. The presence of mitral and/or aortic valvular calcifications (VC) was also evaluated.
Statistical analyses
The data were processed by IBM SPSS Statistics, version 23.0 (IBM Corp., Armonk, NY, USA). Numbers or percentages were used for categorical variables. For continuous variables, data with normal distributions were expressed as means with SDs, while those with skewed distributions were expressed as medians with interquartile ranges. For continuous data with satisfied normality, t test was used to compare between two groups; otherwise, nonparametric test was used. χ2 test was used for comparison between categorical variables. The repeated measures analysis of variance test was used to compare continuous data with satisfied normality for the same group at different time points, and the Friedman test with those with skewed distributions. The area under the curve for predictors of CVE was calculated by receiver-operating characteristic analysis and the cutoff points were determined. A P value of less than 0.05 was considered statistically significant.
| Results | | |
A total of 70 patients were enrolled in our study, 40 females and 30 males with a median age of 42 (25.53) years. The etiologies of ESRD were hypertensive kidney disease (42.9%), chronic glomerulonephritis (14.3%), chronic obstructive uropathy (8.6%), chronic pyelonephritis (5.7%), Alport’s disease (1.4%), nephrocalcinosis (1.4%), polycystic kidney disease (1.4%), and idiopathic causes (24.3%). The median duration on HD was 72 months (30.96). The average body mass index was 24.83 ± 6.38 kg/m2. Thirty-three patients were hypertensive. [Table 1] and [Table 2] present the baseline characteristics of the study population. | Table 1: Baseline demographic data of the total study population and the neutrophil-to-lymphocyte ratio change (1–12) groups versus the percentage of monocyte–lymphocyte ratio change (1–12) groups
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 | Table 2: Laboratory findings of the total study population and the neutrophil-to-lymphocyte ratio change (1–12) groups versus the monocyte–lymphocyte ratio change (1–12) groups
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The patients were followed up for 12 months with baseline hs-CRP and transthoracic echocardiography done at the beginning (before) and after 12 months (after). Ejection fractions at baseline were more than 50%. Of the patients, 52.9% had baseline VC as shown in [Figure 2]. The left ventricular (LV) mass (g) and LVM index (g/m2) were measured at both times. NLR and MLR changes from baseline to after 12 months were compared. The NLR change (1–12) was calculated as a percentage of change (NLR after 12 months – NLR baseline)/NLR baseline ×100) and the MLR change (1–12) calculated as a percentage of change (MLR after 12 months – MLR baseline)/MLR baseline×100). Each was divided into two groups; a decreased group with a decrease in the NLR or MLR after 12 months and an increased group with an increase in the NLR or MLR after 12 months as shown in [Table 1][Table 2][Table 3]. We found no significant relation between NLR decrease/increase or MLR decrease/increase after 12 months and baseline characteristics, and laboratory or echocardiographic findings except for VC. Patients with VC have an increase in their NLR and MLR after 12 months and the vice versa for those with no VC (P=0.004 and 0.001, respectively).  | Table 3: Echocardiographic findings of the total study population and the neutrophil-to-lymphocyte ratio change (1–12) groups versus the monocyte–lymphocyte ratio change (1–12) groups
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The leukocyte counts, NLR and MLR, and hemoglobin levels were followed up in the study population at baseline, after 3months, after 6 months, after 9 months, and after 12 months as shown in [Table 4] and [Figure 3]. | Table 4: Analysis of the values of the total leukocyte, neutrophil, lymphocyte and monocyte absolute counts, neutrophil-to-lymphocyte ratio, monocyte–lymphocyte ratio and hemoglobin level at baseline, after 3, 6, 9, and 12 months
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 | Figure 3: Leukocyte counts change over time: (a) neutrophil absolute counts and (b) monocyte absolute counts.
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We then studied the relation between the change in either NLR or MLR from baseline to after 12 months with the percentage of change of each of NLR, MLR, hs-CRP, LV mass, and LVM index after 12 months as shown in [Table 5]. There was a linear significant relation between the NLR change and MLR change (P=0.000) as shown in [Figure 4]. | Table 5: Total study population versus both the neutrophil-to-lymphocyte ratio change (1–12) groups and the monocyte–lymphocyte ratio change (1–12) groups in relation to the percentage of change of laboratory and echocardiographic findings after 12 months
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 | Figure 4: The linear relation between % of change of NLR and % of change of MLR. MLR, monocyte–lymphocyte ratio; NLR, neutrophil-to-lymphocyte ratio.
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The patients were also followed up for the incidence of any major CVE. Five patients developed CVE with no incident mortality. One patient developed transient ischemic attack after 2 months from the beginning of the study in the form of right-sided weakness that resolved in the same day without evident infarction in the MRI of the brain, but he was discovered to have paroxysmal atrial fibrillation. One patient developed acute coronary syndrome after 4 months in the form of inferior ST segment elevation myocardial infarction, diagnosed by 12-lead electrocardiography, and underwent cardiac catheterization with insertion of a drug-eluting stent in the right coronary artery. Another one had unstable angina at the end of the study confirmed by echocardiography, and underwent a percutaneous coronary angiography that showed nonsignificant atherosclerotic lesions in the left anterior descending and left circumflex coronary arteries. One patient was accidently discovered to have ischemic cardiomyopathy at the end of the study with a decrease in the ejection fraction from 64% at the beginning of the study to 39% after 12 months and was planned for cardiac catheterization. One patient developed pulmonary embolism and biventricular failure after 8 months of the study and was kept on lifelong warfarin anticoagulation. [Table 6][Table 7][Table 8][Table 9] present the baseline characteristics, and laboratory and echocardiographic findings of the patients who developed CVE in relation to those with no CVE. The mean total iron-binding capacity was significantly higher in patients with CVE (P=0.032). The mean monocyte counts at baseline, after 6 months, and after 12 months were significantly higher in the patients with CVE (0.69 ± 0.17, 0.72 ± 0.11, 0.73 ± 0.20 × 103/µl), respectively, compared with those with no CVE (0.47 ± 0.18, 0.52 ± 0.17, 0.52 ± 0.18 × 103/µl), respectively (P=0.010, 0.010, and 0.015, respectively). The median LV mass after 12 months of the study was higher in patients with CVE 278.04 g (213.26–298.24 g) compared with those with no CVE 179.96 g (135.8–226.38 g) (P=0.01). Changes in NLR and MLR after 6 and 12 months and in echocardiographic findings after 12 months in those with CVE were not significant. | Table 6: Patients who developed major cardiovascular events versus those with no cardiovascular event in relation to baseline demographic data
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 | Table 7: Patients who developed major cardiovascular events versus those with no cardiovascular event in relation biochemical findings
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 | Table 8: Patients who developed major cardiovascular events versus those with no cardiovascular event in relation to peripheral blood cell count findings
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 | Table 9: Patients who developed major cardiovascular events versus those with no cardiovascular event in relation to echocardiographic findings
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An receiver-operating characteristic analysis for the most powerful predictors of major CVE ([Figure 5]) with a sensitivity of 100% showed that the monocyte absolute count has a cutoff point of more than 0.54 103/µl followed by the total iron-binding capacity with a cutoff point of more than 232.6 ug/dl and lastly the baseline ejection fraction with a cutoff point of less than or equal to 64% as shown in [Table 10]. | Figure 5: Graph of the ROC curves showing area under the curve of the predictors of major cardiovascular events. ROC, receiver-operating characteristic.
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 | Table 10: Cutoff points for monocyte absolute count, total iron-binding capacity, and ejection in predicting major cardiovascular events
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| Discussion | | |
CV complications and atherosclerosis in chronic kidney disease are due to the interaction between traditional risk factors such as hypertension, smoking or dyslipidemia, and inflammation [8]. Chronic inflammation, evident by CRP and proinflammatory cytokine in ESRD, has direct proatherogenic effects [9]. Inflammation is not only a phenomenon of plasma acute-phase proteins but also of alterations in circulating pools of blood immune cells [8].
From the point of view that the blood counts are changeable over time [10], we reported leukocyte counts, NLR, and MLR at different times. This is in contrast to the single reading determination of NLR in the Abe et al. [11] study and of MLR in the Xiang et al. [12] study. We found significant increases in neutrophils and monocytes over time. To date, our study is the first to study changes in NLR and MLR readings over time and their relation to different variables in ESRD population and CVE prediction. The NLR and MLR have a linear relation as also demonstrated by Xiang et al. [12].
We excluded patients aged more than 60 years, those with diabetes, ejection fraction of less than 50%, autoimmune diseases, malignancies or active infections, and the arteriovenous fistula was the vascular access to avoid major effects on circulating cells or increased CV risk. In Xiang et al. [12] study, a total of 355 ESRD patients with a mean age of 58.0 ± 14.9 years on regular HD for more than 6 months, 18.6% having diabetes mellitus, and 73.8% having hypertension were followed up for a median of 51 months for all-cause and CV mortality. In our study, 70 ESRD patients with a median age of 42 years (25, 53 years), on regular HD for more than 6 months, with 47.1% having hypertension, were followed up for 12 months for the occurrence of major CVE. There were no reported mortality cases in our study, which may be attributed to our exclusion criteria, besides, our shorter follow-up period. In the Xiang et al. [12] study, the increased MLR was an independent predictor of total and CV mortality and in HD patients the highest survival rates were in patients with the lowest NLR tertile (< 2.72). In our study, the median NLR in the follow-up months ranged between 2.32 and 2.59, which may also explain the absence of mortality. However, we found no significant difference in MLR readings or even the change in MLR after 12 months between patients who developed CVE and those with no CVE. Abe et al. [11] studied a total of 86 ESRD patients (58 men and 28 women) who had just started dialysis, with a mean age of 58 ± 11 years and 48.8% having diabetes for incidence of CVE over a median observational period of 38.7 months. Seventy-nine patients were started on HD through either fistula, graft or double-lumen catheter and seven patients on peritoneal dialysis. CVE were more frequent in patients with NLR more than median of 2.54 than in those with NLR less than median of 2.54, and the incidence increases with higher quartiles of NLR. In our study, the median NLR at baseline in patients with CVE was 2.5 (2.07, 2.56) which lies in the first quartile of NLR (1.19–2.78) in the Abe et al. [11] study, which may explain a part the few amount of CVE in our study, besides, our exclusions in contrast to the Abe et al. [11] study. However, we found no significant relation between NLR at different times or even the change in NLR with the occurrence of CVE. We failed to relate CVE occurrence to changes in CRP levels after 12 months as in the Abe et al. [11] study, which may be attributed to our exclusion criteria.
CV calcification is highly prevalent in patients with ESRD due to interactions between the endothelium, vascular/valvular cells, and monocyte-derived macrophages [13]. It can lead to the development of myocardial ischemia, infarction, impaired myocardial function, cardiac valve insufficiency, and arrhythmias [14]. In our study, 52.9% of the patients had VC (64.9% aortic, 5.4% mitral, and 29.7% in both). Tarrass et al. [15] studied 90 patients on maintenance HD for more than 12 months with a mean age of 45.6 ± 13.6 years, a total of 40% had VC (25% aortic, 11% mitral, and 64% in both valves). Varol et al. [16] showed in their study in 2014 that NLR ratio in a single reading was significantly higher in patients with mitral annular calcification than in control individuals (P<0.001) and was correlated with mitral annular calcification. Here, we found a highly significant positive relation between the presence of VC and the increase in both NLR and MLR readings after 12 months (P=0.004 and 0.001, respectively), which emphasizes an ongoing inflammatory process in those patients.
The CD14+/CD16+ monocytes are abnormally high in both dialyzed and nondialyzed patients with chronic kidney disease. They contribute to the prevalent oxidative stress and systemic inflammation and favor the progression of atherosclerotic plaques in ESRD [13]. This is mediated by oxidative modification of low-density lipoproteins that are then uptaken by macrophages and are transformed to foam cells. There is also the oxidative activation of endothelial cells, which results in the adhesion of monocytes to the endothelium and their penetration in the subendothelial space followed by their proliferation, transformation into foam cells, plaque formation, plaque rupture, and thrombosis [17]. Studies have found that elevated monocyte counts are independently related to all-cause and CV mortality in HD patients [12]. Koraishy et al. [18] followed a national cohort of 1 706 589 US veterans without ESRD over a median of 9.16 years. A monocyte count more than 0.56 × 103/µl was associated with an increased risk of death overall and across each estimated glomerular filtration rate category (P<0.001). In our study, the monocyte count was higher in patients who developed CVE throughout the follow-up periods than in those with no CVE with a cutoff point of more than 0.54 × 103/µl for baseline monocyte counts.
There are some limitations in our study. It is a small cohort from a single-center and we need a larger multicentric study population to be more representative. The average follow-up period needs to be expanded for years to follow up patients for the incidence of more CVE and mortality. We recommend to compare with diabetic ESRD patients and with patients with baseline heart failure or ejection fractions of less than 50%.
| Conclusions | | |
In ESRD, leukocyte counts are in a dynamic change. There was no significant change in NLR or MLR over time, and their change could not predict the occurrence of major CVE. The monocyte count is an excellent predictor of CV diseases in ESRD. The presence of VC is associated with increases in both NLR and MLR over time.
Acknowledgements
The authors express their thanks to the dialysis unit staff, the Cardiology Department Staff, and all the patients who participated in this study.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10]
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