• Users Online: 3163
  • Print this page
  • Email this page

 
Table of Contents
ORIGINAL ARTICLE
Year : 2022  |  Volume : 11  |  Issue : 3  |  Page : 144-149

Impact of haemodialysis on cardio-metabolic burden in chronic kidney disease patients - A prospective cohort study


1 Cardiology Unit, Department of Medicine, Cedarcrest Hospitals, Gudu, Abuja, Nigeria
2 Division of Endocrinology and Diabetes, Department of Internal Medicine, Al Isawiya General Hospital, Ministry of Health, Directorate of Al Gurayat, Al Qurayyat, Kingdom of Saudi Arabia
3 Department of Community Medicine, Nnamdi Azikiwe University Teaching Hospital, Nnewi, Anambra, Nigeria
4 Department of Internal Medicine, Faculty of Medicine, College of Health Sciences, Nnamdi Azikiwe University, Nnewi Campus, Nnewi, Anambra, Nigeria

Date of Submission21-Jan-2022
Date of Decision13-Feb-2022
Date of Acceptance08-Mar-2022
Date of Web Publication08-Jun-2022

Correspondence Address:
Chikezie Hart Onwukwe
Al Isawiya General Hospital, Ministry of Health, Directorate of Al Gurayat, Al Qurayyat 77471
Kingdom of Saudi Arabia
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jcsr.jcsr_8_22

Rights and Permissions
  Abstract 


Background: Maintenance haemodialysis (MHD) is the major form of renal replacement therapy in Nigeria, and may have a significant impact on cardiovascular (CV) and metabolic burden in chronic kidney disease (CKD) patients.
Methods: This is a prospective cohort study involving 40 CKD dialysis-naïve end-stage renal disease patients who were assessed at first contact before commencing dialysis and assessments repeated 3 months later while on MHD. Clinical, echocardiographic and biochemical indices were assessed on both occasions. We studied the impact of MHD on CV risk factors such as left ventricular hypertrophy, left ventricular ejection fraction (LVEF), high calcium-phosphate product, hypoalbuminaemia, anaemia and dyslipidaemia.
Results: The mean serum calcium-phosphate product, plasma total cholesterol, triglycerides and low-density lipoprotein cholesterol were significantly higher at baseline than at three months; while the mean haemoglobin, serum albumin and plasma high-density lipoprotein were significantly lower at baseline than at 3 months (P < 0.01). There was a significant difference in echocardiographic indices at baseline and at 3 months in CKD patients on MHD. Left ventricular mass and left ventricular mass index were significantly higher at baseline than at 3 months (P < 0.01); while LVEF was significantly lower at baseline than at 3 months (P < 0.01).
Conclusion: Our study showed statistically significant improvements in CV risk factors among CKD patients after 3 months on maintenance haemodialysis. Early and effective maintenance haemodialysis reduce CV risk factors in Nigerian CKD patients.

Keywords: Cardiovascular, chronic kidney disease, left ventricular hypertrophy, metabolic, Nigeria, Risk factors


How to cite this article:
Okorie KK, Onwukwe CH, Chikezie NI, Kalu O, Osuji CU. Impact of haemodialysis on cardio-metabolic burden in chronic kidney disease patients - A prospective cohort study. J Clin Sci Res 2022;11:144-9

How to cite this URL:
Okorie KK, Onwukwe CH, Chikezie NI, Kalu O, Osuji CU. Impact of haemodialysis on cardio-metabolic burden in chronic kidney disease patients - A prospective cohort study. J Clin Sci Res [serial online] 2022 [cited 2022 Aug 12];11:144-9. Available from: https://www.jcsr.co.in/text.asp?2022/11/3/144/347047




  Introduction Top


Chronic kidney disease (CKD) is a major cause of cardiovascular (CV) morbidity and mortality worldwide which accounts for significant proportions of death in Nigeria and most parts of Africa.[1],[2] Haemodialysis is indicated for the treatment of acute kidney injury, acute exacerbation of chronic renal failure and end-stage renal disease (ESRD).[1] It is the most widely available form of renal replacement therapy in Nigeria and sub-Saharan Africa.[2] There are several reports on the effects of maintenance haemodialysis (MHD) on some CV risk factors among CKD patients.[3],[4],[5],[6],[7],[8],[9],[10],[11] To the best of our knowledge, this is the first prospective cohort study in Nigeria carried out on CKD patients to determine the impact of haemodialysis on CV risk factors. This study provides insight on the impact of haemodialysis on some common CV risk factors and may help in advocacy for effective and adequate MHD among CKD patients.


  Material and Methods Top


This study was approved by the Nnamdi Azikiwe University Teaching Hospital (NAUTH), Nnewi Research and Ethics Committee after conforming with the committee guidelines Certificate dated 4 March 2016, reference number NAUTH/CS/66/VOL8/39).

This was a prospective cohort involving CKD patients attending the adult renal clinic of the NAUTH, Nnewi, Nigeria. The study included consenting patients aged above 18 years with confirmed diagnosis of CKD irrespective of primary aetiology who were dialysis-naive at first contact. Patients with pregnancy, post-renal transplant and malignancy were excluded. The sample size for this study was calculated using the formula for comparing means between two independent groups from a similar study:[12] In a similar study by Duran et al.,[13] haemoglobin (Hb) levels were compared in ESRD patients pre- and post-haemodilaysis. The pre-intervention Hb was 9.8 ± 1.4 G/DL, while the post-intervention Hb was 11.2 ± 1.3 G/DL. Using these values and assuming that Z1-α/2 for a significance level of 0.05 is 1.96 while the Z1-β for a statistical power of 80% is 0.84, the sample size was calculated thus. Hence to allow for 10% attrition, a total minimum sample size of 17 was calculated.

Participants were commenced on three sessions of conventional haemodialysis weekly and assessments were done just before commencement of MHD and at 3 months on MHD. Clinical data were obtained at initiation and 3 months on haemodialysis. History of uraemic symptoms was obtained from participants. The weight (in kilograms) and height (in metres) of the study participants were determined using the World Health Organization (WHO) STEPwise approach to surveillance (STEPS) tool.[14] Body mass index (BMI) was calculated as weight (in kilograms) divided by the square of the height (in metres). Obesity was defined as BMI ≥30 Kg/m2.[15] Blood pressure (BP) was measured with a mercury sphygmomanometer (Accoson Greenlight 300) in the sitting position with the appropriate cuff based on patients' arm sizes. Systolic and diastolic BP were measured using the American Society of Hypertension guidelines.[16] Systolic BP ≥140 mmHg, and/or diastolic BP ≥90 mmHg, or use of antihypertensive drug treatment defined hypertension.[17]

Ten mL of peripheral venous blood was collected from each individual between 8 am and 10 am after overnight fast of 8 to 12 H. Two millilitres of the sample was put in an ethylenediaminetetraacetic acid bottle for haemoglobin estimation and the remaining 8 mL was placed in a plain tube for phosphate, calcium, albumin, creatinine and lipid estimation. Haemoglobin was determined using a HemoCue Hb photometer.[18] Serum phosphate levels were estimated using the Fiske-Subbarow method.[19] Total serum calcium estimation was done using the cresolphthalein-complexone method.[20] Serum albumin estimation was determined using bromocresol green colorimetric dye method.[21] Serum creatinine estimation was done using the fixed-time kinetic method.[22] The concentrations of total cholesterol, triglycerides, low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol were measured by enzymatic colorimetric methods using an auto-analyzer (Roche Diagnostics GmbH, Mannheim, Germany).

Transthoracic M-mode, two-dimensional echocardiography was performed on study participants using an echocardiography machine (Esaote Europe, Aj Maastricht, The Netherlands). Two-dimensional views were used for the real-time description of cardiac morphology and as reference for M-mode beam selection. The echocardiographic assessment was made based on the American Society of Echocardiography guidelines.[23]

Left ventricular hypertrophy was defined as left ventricular mass index >115 g/m2 (in men) and >95 g/m2 (in women).[24] Left ventricular systolic dysfunction was defined as left ventricular ejection fraction (LVEF) <55%.[24]

For quality assurance, two cardiologists performed the echocardiography procedure and measured the echocardiographic indices to reduce intra-observer bias.

Estimated glomerular filtration rate (eGFR) was determined using the modification of diet in renal disease formula as follows:[25]

eGFR = 186 × (Scr)−1.154 × (age)−0.203 × (0.742 if female) × (1.210 if black), where Scr = serum creatinine (mg/dL).

CKD was defined as per the Kidney Disease Improving Global Outcomes guideline.[26] The indications for haemodialysis include any of eGFR <30 mL/Min/1.73 m2, severe hyperkalaemia (serum potassium more than 6.5 mM/L), severe metabolic acidosis (serum bicarbonate <15 mM/L), serum urea more than 30 mM/L, serum creatinine more than 700 μM/L and clinical features of uraemia.[26]

Hb level <13.5 g/dL (in males) and <12 g/dL (in females) are defined anaemia.[26] Hypoalbuminaemia was defined as serum albumin <3.5 g/dL[24] while calcium-phosphate product (in mg2/dL2) was calculated as serum calcium (mg/dL) multiplied by serum phosphate (mg/dL). Calcium-phosphate product above 55 mg2/dL2 was considered elevated.[26]

Dyslipidaemia was defined as any or a combination of the following: total cholesterol >200 mg/dL, low-density lipoprotein cholesterol >130 mg/dL, triglycerides >150 mg/dL or low high-density lipoprotein cholesterol (defined as high-density lipoprotein cholesterol <40 mg/dL in males and <50 mg/dL in females).[27]

Statistical analysis

Collected data were entered in study proforma and transferred to the Statistical Package for the Social Sciences version 20 (IBM Corporation, California, USA) for statistical analysis. Illustration of analysed data was done using tables. Determination of normality was done using the Kolmogorov–Smirnov test. Quantitative variables were presented as mean ± standard deviation (SD) for normally distributed data or median (smallest value, highest value) for skewed data while qualitative variables were presented as proportions, No. (%). Comparison of quantitative variables was made using paired sample t-test for parametric data and Mann–Whitney U-test for skewed data., Chi-square test was used to compare proportions. P < 0.05 defined statistical significance.


  Results Top


Fifty-seven haemodialysis naïve patients commenced this study, but 40 participants with complete data completed the study and their data analysed. Of these 40 participants, 18 were male, while 22 were female. There was no statistically significant sex difference among study participants (P = 0.52). All the patients were in stage 5 CKD. The most common cause of CKD was hypertensive nephrosclerosis (occurring in 35% of participants), followed by a combination of hypertensive/diabetic nephropathy in 20% [Table 1].{Table 1}

Uraemic symptoms significantly reduced at 3 months (P < 0.05) while BMI of maintenance haemodialysis participants was significantly higher at 3 months than at baseline (P = 0.03). The BP (systolic and diastolic), serum phosphate, calcium phosphate product, plasma TC, plasma TG and plasma LDL-C were significantly higher at baseline than at 3 months while haemoglobin, serum calcium, serum albumin and plasma HDL-C. There was a significant change in eGFR at baseline (Median eGFR 19 mL/Min/1.73 m2, range [9, 52)) and 3 months post commencement of dialysis (Median eGFR 87 mL/Min/1.73 m2, range [22, 168)), P < 0.01.The mean Hb was significantly found to be higher (12.14 ± 1.09) after 3 months of maintenance haemodialysis than at baseline (9.44 ± 2.95), P < 0.01. Serum albumin was significantly higher after 3 months (3.92 ± 0.21) on maintenance haemodialysis than at baseline (3.40 ± 0.30), P < 0.01. There was a significant reduction in the mean level of calcium-phosphate product from (53.96 ± 11.91) at baseline to (37.53 ± 6.82) after 3 months on maintenance haemodialysis.

There were significant differences in echocardiographic indices at baseline and at 3 months in CKD patients on maintenance haemodialysis. The mean LVMI among patients on haemodialysis was significantly higher at baseline (150.48 ± 46.43) than at 3 months (94.16 ± 25.39) (P < 0.01). The mean LVEF was higher at 3 months (60.72 ± 6.39) compared to baseline (48.02 ± 5.32), P < 0.01 [Table 2].{Table 2}


  Discussion Top


In this study, we found a significant reduction in LVMI after 3 months of maintenance haemodialysis in the study participants. We also found a significant reduction in the means of systolic and diastolic pressures among our patients after 3 months on maintenance haemodialysis This is similar to the findings among 19 hypertensive CKD patients on haemodialysis in Turkey.[8] Reduction in LVMI may be attributed to improvement in BP, alterations in fluid dynamics and improvement in cardiac structure. Haemodialysis is known to reduce intravascular volume overload, sodium retention and preload. These subsequently reduce systemic BP and cardiac remodelling.[8] A study[5] of 24 patients on haemodialysis in Perugia, Italy made similar observations of reduction of LVMI, BP and fluid overload after 3 months of maintenance haemodialysis. A prospective cohort study[6] of 227 patients who had echocardiography at inception and after 1 year of dialysis, found improvements in LVMI, volume index and fractional shortening in 48%, 48% and 46% of participants respectively. This study clearly demonstrated regression of LV abnormalities with improved outcomes in dialysis patients.[6] These findings are similar to the index study, and clearly show improvements in LV structure and systolic function among CKD patients on maintenance haemodialysis.[5],[6],[8]

The participants of our study had a significant increase in mean LVEF from 48.02% ± 5.3% to 60.72% ± 6.4% after 3 months of maintenance haemodialysis. This is similar to previous reports.[28],[29] An LVEF rise from 42% to 52% in stable haemodialysis CKD patients after serial haemodialysis and 44% to 59% in CKD patients on ultrafiltration has been reported.[28] Similar significant increase in LVEF (28% ± 12% to 41% ± 18%, P = 0.01) in ESRD patients with congestive cardiac failure after undergoing nocturnal haemodialysis for 3.2 ± 2.1 years has also been reported.[29] There are suggestions that decrease in end-diastolic volume and increase in the cardiac contractile state are responsible for the observed rise in LVEF in CKD patients on dialysis. It is also thought that uremic toxins have vasoconstrictor and myocardial depressant actions. The combined effects of removal of these toxins and decrease in EDV during dialysis improves left ventricular function.[28]

We found a statistically significant reduction in total cholesterol, TG and LDL-C and an increase in HDL-C after three months on maintenance haemodialysis. This could be explained by the reduction in the level of uremic toxins by haemodialysis.[4] There are conflicting reports from previous studies on the effect of haemodialysis on lipid fractions in CKD patients.[30],[31],[32] Low HDL-C and elevated LDL-C levels have been reported in patients on maintenance haemodialysis.[31] Differences in patient characteristics and study design may explain the differences. They recruited predominantly Caucasians and patients with diabetic nephropathy, unlike the index study that was primarily on Africans, with hypertensive nephrosclerosis as the major cause of CKD. Furthermore, our study did not exclude patients on statins and this could have also affected the differences in lipid patterns. In another study[32] involving 21 haemodialysis and 40 peritoneal dialysis patients, there was a significant decreasing trend in TC and LDL-C values. This is similar to the finding in this index study.

In our study, the mean haemoglobin significantly increased from 9.44 ± 2.95 G/DL to 12.14 ± 1.09 G/DL after 3 months of maintenance haemodialysis. Reduction in the levels of uraemic toxins, improvement in oral intake and possible intra-dialysis blood transfusions are possible explanations for this improvement after 3 months. This finding is similar to the result of a previous study in Sudan.[11]

Serum albumin was significantly higher after 3 months (3.92 ± 0.21 G/DL) on maintenance haemodialysis than at baseline (3.40 ± 0.30 G/DL), P < 0.01. This is similar to the observations made in a study[10] from Taiwan, which showed that increasing the dose of dialysis improved serum albumin levels and survival rate in haemodialysis patients. A 12% to 13% rise in serum albumin after 6 months of haemodialysis has been reported.[7] Those with increase in serum albumin levels had fewer incidences of CV events after 1 year of haemodialysis. The determinants of the rise in serum albumin in haemodialysis patients are unknown, however possible logical reasons must include a combination of the increased rate of synthesis, decrease rate of loss and reduction in metabolic acidosis and catabolism.[7]

There was a significant reduction in the mean level of calcium-phosphate product from (53.96 ± 11.91) at baseline to (37.53 ± 6.82) after 3 months on maintenance haemodialysis. This is similar to a previous study[3] which found the reduction in the calcium-phosphate product more in haemodiafilteration than in intermediate HD group.

The eGFR at baseline rose significantly from a median value of 19 mL/Min/1.73 m2 to 87 mL/Min/1.73 m2 at 3 months. The eGFR at baseline may have been as a result of an acute insult on an existing CKD with dialysis and other medical treatments improving the kidney function towards normalcy at 3 months follow-up. At this stage, dialysis is not required as most of the time patients will be successively managed conservatively with medical management only.

The limitation of our study was the short duration of follow-up of patients. This study has demonstrated that maintenance haemodialysis reduces CV and metabolic risk factors among CKD patients. Left ventricular mass index, LVEF, lipid abnormalities, anaemia, high-calcium phosphate product, hypoalbuminaemia and systemic BP showed remarkable improvements after 3 months of maintenance haemodialysis. This shows that early and effective maintenance haemodialysis may reduce cardio-metabolic burden and mortality among ESRD patients in Nigeria.

The significant rise in eGFR following 3 months of haemodialysis may imply the presence of acute on CKD in the study participants. Hence, improvement in cardio-metabolic burden could be as a result of effective medical and dialysis treatments with mitigation of acute injury on existing CKD.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Afolabi MO, Abioye-Kuteyi EA, Arogundade FA, Bello IS. Prevalence of chronic kidney disease in a Nigerian family practice population. S Afr Fam Pract 2009;51:132-7.  Back to cited text no. 1
    
2.
Odetola TA, Ositelu SB, Almeida SA, Mabadeya AF. Five years experience of hemodialysis at the Lagos university teaching hospital. Afr J Med 1989;18:193-201.  Back to cited text no. 2
    
3.
Davenport A, Gardner C, Delaney M; Pan Thames Renal Audit Group. The effect of dialysis modality on phosphate control: Haemodialysis compared to haemodiafiltration. The pan Thames renal audit. Nephrol Dial Transplant 2010;25:897-901.  Back to cited text no. 3
    
4.
Baugh ME, Stoltz ML, Vanbeber AD, Gorman MA. Are lipid values and BMI related to hospitalizations in the hemodialysis population? J Ren Nutr 2001;11:37-45.  Back to cited text no. 4
    
5.
Fagugli RM, Pasini P, Pasticci F, Ciao G, Cicconi B, Buoncristiani U. Effects of short daily hemodialysis and extended standard hemodialysis on blood pressure and cardiac hypertrophy: A comparative study. J Nephrol 2006;19:77-83.  Back to cited text no. 5
    
6.
Foley RN, Parfrey PS, Kent GM, Harnett JD, Murray DC, Barre PE. Serial change in echocardiographic parameters and cardiac failure in end-stage renal disease. J Am Soc Nephrol 2000;11:912-6.  Back to cited text no. 6
    
7.
Goldwasser P, Kaldas AI, Barth RH. Rise in serum albumin and creatinine in the first half year on hemodialysis. Kidney Int 1999;56:2260-8.  Back to cited text no. 7
    
8.
Ozkahya M, Toz H, Qzerkan F, Duman S, Ok E, Basci A, et al. Impact of volume control on left ventricular hypertrophy in dialysis patients. J Nephrol 2002;15:655-60.  Back to cited text no. 8
    
9.
Vaziri ND, Moradi H. Mechanisms of dyslipidemia of chronic renal failure. Hemodial Int 2006;10:1-7.  Back to cited text no. 9
    
10.
Yang CS, Chen SW, Chiang CH, Wang M, Peng SJ, Kan YT. Effects of increasing dialysis dose on serum albumin and mortality in hemodialysis patients. Am J Kidney Dis 1996;27:380-6.  Back to cited text no. 10
    
11.
Hakim YA, Abass AA, Khalil A, Mustafa HI. The effect of hemodialysis on hemoglogbin concentration, platelets count and white blood cells in end stage renal failure. Int J Med Res Health Sci 2016;5:22-35.  Back to cited text no. 11
    
12.
Rosner B. Fundamentals of Biostatistics. 7th ed. Boston: Brooks/Cole Cengage Learning; 2011. p. 301-3.  Back to cited text no. 12
    
13.
Duran M, Unal A, Inanc MT, Esin F, Yilmaz Y, Ornek E. Effect of maintenance hemodialysis on diastolic left ventricular function in end-stage renal disease. Clinics (Sao Paulo) 2010;65:979-84.  Back to cited text no. 13
    
14.
WHO Steps Manual. Available from: http://www.who.int/chp/steps/manual/en/html. [Last accessed on 2020 Sep 19].  Back to cited text no. 14
    
15.
Obesity: Preventing and managing the global epidemic. Report of a WHO consultation. World Health Organ Tech Rep Ser 2000;894:i-253.  Back to cited text no. 15
    
16.
Recommendations for routine blood pressure measurement by indirect cuff sphygmomanometry. American society of hypertension. Am J Hypertens 1992;5:207-9.  Back to cited text no. 16
    
17.
Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, Izzo JL Jr., et al. Seventh report of the joint national committee on prevention, detection, evaluation, and treatment of high blood pressure. Hypertension 2003;42:1206-52.  Back to cited text no. 17
    
18.
Nkrumah B, Nguah SB, Sarpong N, Dekker D, Idriss A, May J, et al. Hemoglobin estimation by the HemoCue® portable hemoglobin photometer in a resource poor setting. BMC Clin Pathol 2011;11:5.  Back to cited text no. 18
    
19.
Fiske CH, Subba RY. The colorimetric determination of phosphorus. J Biol 1925;66:375-81.  Back to cited text no. 19
    
20.
Baron DN, Bell JL. Compleximetric determination of calcium in pathological and physiological specimens. J Clin Pathol 1959;12:143-8.  Back to cited text no. 20
    
21.
Kumar D, Banerjee D. Methods of albumin estimation in clinical biochemistry: Past, present, and future. Clin Chim Acta 2017;469:150-60.  Back to cited text no. 21
    
22.
Davis GA, Chandler MH. Comparison of creatinine clearance estimation method in patients with trauma. Am J Health Syst Pharm 1996;53:1028-32.  Back to cited text no. 22
    
23.
Sahn DJ, DeMaria A, Kisslo J, Weyman A. Recommendations regarding quantitation in M-mode echocardiography: Results of a survey of echocardiographic measurements. Circulation 1978;58:1072-83.  Back to cited text no. 23
    
24.
Lang RM, Bierig M, Devereux RB, Flachskampf FA, Foster E, Pellikka PA, et al. Recommendations for chamber quantification. Eur J Echocardiogr 2006;7:79-108.  Back to cited text no. 24
    
25.
Agaba EI, Wigwore CM, Agaba PA. Performance of cockroft gault and MDRD equation in adult Nigerians with chronic kidney disease. Int Urol Nephrol 2001;41:635-42.  Back to cited text no. 25
    
26.
KDIGO. 2012 clinical practice guideline for the evaluation and management of chronic kidney disease. Kidney Int Suppl 2013;3:5-70.  Back to cited text no. 26
    
27.
Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Executive summary of the third report of the national cholesterol education program (NCEP) expert panel on detection, evaluation, and treatment of high blood cholesterol in adults (Adult treatment panel III). JAMA 2001;285:2486-97.  Back to cited text no. 27
    
28.
Nixon JV, Mitchell JH, McPhaul JJ Jr., Henrich WL. Effect of hemodialysis on left ventricular function. Dissociation of changes in filling volume and in contractile state. J Clin Invest 1983;71:377-84.  Back to cited text no. 28
    
29.
Chan C, Floras JS, Miller JA, Pierratos A. Improvement in ejection fraction by nocturnal haemodialysis in end-stage renal failure patients with coexisting heart failure. Nephrol Dial Transplant 2002;17:1518-21.  Back to cited text no. 29
    
30.
Ma KW, Greene EL, Raij L. Cardiovascular risk factors in chronic renal failure and hemodialysis populations. Am J Kidney Dis 1992;19:505-13.  Back to cited text no. 30
    
31.
Pennell P, Leclercq B, Delahunty MI, Walters BA. The utility of non-HDL in managing dyslipidemia of stage 5 chronic kidney disease. Clin Nephrol 2006;66:336-47.  Back to cited text no. 31
    
32.
Al-Hwiesh A. Study of lipid abnormalities in patients maintained on haemodialysis or automated peritoneal dialysis in the Eastern province of Saudi Arabia. Open Access Sci Rep 2012;1:346.  Back to cited text no. 32
    




 

Top
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
Abstract
Introduction
Material and Methods
Results
Discussion
References

 Article Access Statistics
    Viewed405    
    Printed15    
    Emailed0    
    PDF Downloaded56    
    Comments [Add]    

Recommend this journal