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Saudi Journal of Kidney Diseases and Transplantation
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Table of Contents   
ORIGINAL ARTICLE  
Year : 2011  |  Volume : 22  |  Issue : 4  |  Page : 689-694
Dyslipidemia in dialysis patients


1 Division of Nephorology, Department of Medicine, King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia
2 Department of Family and Community Medicine, King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia
3 College of Medicine and Research Center, King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia

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Date of Web Publication9-Jul-2011
 

   Abstract 

In order to evaluate the lipid profiles of dialysis patients, we retrospectively reviewed all the chronic kidney disease (CKD) patients on chronic hemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD), followed up between June 2004 and May 2005, in two tertiary hospitals in Riyadh, Saudi Arabia. There were 380 patients including 206 (54.2%) females and the mean age of the patients was 45.9 ± 15.8 years. The mean dialysis duration was 65.0 ± 58.3 months. Diabetes was present in 97 (25.5%) of the patients and hypertension in 84 (22.1%). Younger patients had more disturbed lipid profile than elderly patients, and females had higher lipid values than males. The CAPD patients had worse lipid profile than those on HD, irrespective of age, sex and duration of dialysis. The presence of diabetes, hypertension, smoking and cardiovascular disease (CVD) all contributed to the worsening of lipid profiles of our patients. Dialysis patients showed improvement in lipid profile initially followed by gradual deterioration. We conclude that dyslipidemia, which increases the risk of CVD by increasing atherogenesis, progresses over time in dialysis patients and becomes worse in CAPD patients.

How to cite this article:
Mitwalli AH, Alam AA, Al Wakeel JS, Isnani AC. Dyslipidemia in dialysis patients. Saudi J Kidney Dis Transpl 2011;22:689-94

How to cite this URL:
Mitwalli AH, Alam AA, Al Wakeel JS, Isnani AC. Dyslipidemia in dialysis patients. Saudi J Kidney Dis Transpl [serial online] 2011 [cited 2019 Aug 20];22:689-94. Available from: http://www.sjkdt.org/text.asp?2011/22/4/689/82645

   Introduction Top


Dyslipidemia is a primary risk factor in the development of a number of disease multitudes ranging from atherosclerosis to stroke. [1],[2] The risk is substantially elevated in patients with end-stage renal disease (ESRD) (such patients show various abnormalities in plasma-lipids and lipoproteins that are called uremic dyslipidemia. [3],[4] Disturbances of lipid transport and metabolism are common complications of chronic renal failure, regardless of the cause of renal disease, which may persist or deteriorate during renal replacement therapy. [4],[5],[6] Patients with chronic kidney disease (CKD) usually have an elevated ratio of low-density lipoprotein (LDL) cholesterol to high-density lipoprotein (HDL) cholesterol. [6],[7],[8],[9],[10]

Dyslipidemia may be worsened by dialysis, especially continuous ambulatory peritoneal dialysis (CAPD). Dyslipidemia among HD patients negatively impacts cardiovascular profiles, which in turn influence the frequency and/or duration of hospitalizations. [11] Patients on CAPD exhibit high levels of total cholesterol (TC) and low density lipoprotein (LDL). [12] After CAPD treatment for more than 12 months, these patients may reveal higher serum triglyceride and total serum cholesterol levels compared to their values before commencing CAPD. This phenomenon is not observed in HD patients, and it should be considered when selecting a dialysis modality given the risk of cardiovascular disease (CVD) in the dialysis population. [12],[13],[14],[15],[16] In addition, cross-sectional studies have found that variable results of lipid levels are related to their duration on dialysis. [17],[18],[19],[20]

Finally, comorbidities may exist in ESRD patients, which act as confounding factors in the acceleration and higher prevalence of macro-vascular complications including ischemic heart disease and cerebrovascular diseases. [16],[21],[22]

The aim of this study was to investigate the changes of lipid profiles among patients undergoing CAPD or HD in relation to duration of dialysis and other biochemical parameters.


   Patients and Methods Top


A cohort study was conducted including all CKD patients on HD or CAPD, between June 2004 and May 2005, attending two tertiary hospitals in Riyadh, Saudi Arabia (King Khalid University Hospital and Riyadh Central Hospital). Retrospective data were collected from dialysis records including age, sex, height, weight, and blood pressure. Other pertinent dialysis data included the cause of renal failure, duration of dialysis, and presence of co-morbid factors (diabetes, cardiovascular and liver disease), smoking history, and hyperparathyroidism. Laboratory parameters included lipid profile [total cholesterol, serum triglycerides, high density cholesterol (HDL) and LDL], fasting blood sugar, urea, and creatinine.


   Statistical Analysis Top


Analysis was performed using the Statistical Package for Social Sciences (SPSS) software volume 11.5. Student's "t" test was performed to correlate the parameters between two normally distributed groups. For independent group analysis, paired t tests were done. A P value of less than 0.05 was considered significant.


   Results Top


Of 380 dialysis patients, 174 (45.8%) were males and 206 (54.2%) were females, with mean dialysis duration of 65.0 ± 58.3 months. The mean age was 45.9 ± 15.8 years. Saudis comprised 354 (93.2%) patients. A total of 338 (89%) of patients were on HD. The remaining 42 (11%) patients were on CAPD. Diabetes was present in 97 (25.5%) of patients, hypertension in 84 (22.1%), unknown cause in 45 (11.8%) and glomerulonephritis in 24 (6.3%). Other causes of chronic renal failure included solitary kidney, obstructive uropathy, vesicoureteral reflux, polycystic kidney disease, neurogenic bladder and tubulointerstitial disease in 130 (34.2%) patients. The mean total cholesterol was 4.16 ± 1.02 mmol/L (range: 2.25-8.3 mmol/L), serum triglyceride was 1.72 ± 0.89 mmol/L (range: 0.3-6.0 mmol/L), HDL was 1.02 ± 0.3 mmol/L (range: 0.3-5.0 mmol/L) and LDL was 2.35 ± 0.84 mmol/L (range: 0.3-5.5 mmol/L).

Among males, hypertension was present in 49 (28.2%) patients followed by diabetes in 40 (23.0%), unknown cause in 20 (11.5%) and glomerulonephritis in 11 (6.3%) patients. Other causes of CKD among males accounted for 54 (31.0%) of patients. In female patients, diabetes (n = 57, 27.7%) was more common than hypertension (n = 35, 17.5%). Unknown cause was noted in 25 (12.1%) patients, while glomerulonephritis was seen in 12 (6.3%) patients. Other causes of CKD among females were noted in 76 (36.9%) patients.

[Table 1] shows the means of the parameters in males and females according to gender. Female patients had higher means of serum levels of the following parameters than males: total cholesterol (4.52 ± 1.07 vs. 3.73 ± 0.77 mmol/ L, P <0.0001), triglycerides (1.87 ± 0.98 vs. 1.54 ± 0.86 mmol/ L, P = 0.0006), HDL (1.06 ± 0.3 vs. 0.98 ± 0.3 mmol/L, P <0.05), and LDL (2.49 ± 0.91 vs. 2.18 ± 0.72 mmol/L, P <0.05). However, the mean serum creatinine levels were significantly higher among male patients (P <0.0001).
Table 1: Lipid profiles and other biochemical parameters in dialysis patients according to gender (n = 380).

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A total of 338 (89%) of patients were on HD and remaining 42 (11%) were on CAPD. [Table 2] shows the lipid profiles of HD patients compared with those on CAPD. The patients on CAPD revealed significantly higher total serum cholesterol levels compared to those on HD (4.72 ± 1.19 vs. 4.09 ± 0.98 mmol/L, P <0.05). Similarly, CAPD patients revealed significantly higher levels of LDL than HD patients (3.06 ± 0.81 vs. 2.26 ± 0.8 mmol/L, P <0.0001).
Table 2: Lipid profiles and other biochemical parameters according to type of dialysis (n = 380).

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HD male patients had significantly lower total serum cholesterol levels compared to those on CAPD (3.64 ± 0.72 vs. 4.27 ± 0.86 mmol/L, P <0.05). Similarly, serum LDL levels were lower among male patients on HD compared to those on CAPD (2.05 ± 0.63 vs. 2.89 ± 0.77 mmol/L, P <0.0001). HDL and serum triglyceride levels among males on CAPD were relatively higher than those on HD; however, the differences between them were insignificant (P = 0.8285 and 0.6443, respectively). Male patients on CAPD were dialyzed for longer duration compared to females on CAPD (42.26 ± 27.2 months vs. 73.59 ± 60.4 months, P = 0.05).

HD females had significantly lower total cholesterol levels compared to females on CAPD (4.45 ± 1.01 vs. 5.44 ± 1.31 mmol/L, P <0.05). Similarly, serum LDL levels were lower among females on HD compared to females on CAPD (2.42 ± 0.88 vs. 3.34 ± 0.81 mmol/L, P <0.05). HDL levels were lower among female CAPD patients compared to females on HD (0.97 ± 0.1 vs. 1.07 ± 0.29 mmol/L, P = 0.1723). Serum triglyceride levels among females on CAPD were relatively higher than the females on HD; however, the differences between them were insignificant (2.18 ± 1.21 vs. 1.84 ± 0.96, P = 0.1843). Females on CAPD were dialyzed for shorter duration than their HD counterparts (39.81 ± 20.6 months vs. 63.5 ± 60.5 months, P = 0.1213).

When patients were categorized according to their duration of dialysis (i.e., the length in months that these patients have been on dialysis, whether HD or CAPD), there were no significant differences seen between those patients undergoing dialysis for less than a year, those undergoing dialysis for 1-5 years or even those undergoing dialysis for more than five years. Relatively, time-wise, those patients who were already on dialysis for more than five years had lower cholesterol levels compared to those less than five years and less than one year. The mean serum cholesterol levels tend to decrease over time more dramatically after five years of dialysis. No significant differences were seen in the triglyceride levels over time. However, serum HDL concentration tended to increase up to five years of dialysis, while serum LDL levels tend to decrease over time on dialysis [Table 3].
Table 3: Lipids and duration of dialysis in all patients (n = 380).

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Diabetic patients were significantly dialyzed for shorter duration than non-diabetic patients (33.5 ± 33.3 years vs. 75.7 ± 61 years, P <0.0001). The mean of serum triglyceride levels was significantly higher among diabetics than non-diabetics (1.99 ± 1.2 mmol/L vs. 1.62 ± 0.82 mmol/L, P <0.05). The other lipid parameters were relatively higher among diabetics than among non-diabetics although the values did not reach significant levels.

Patients with history of cardiovascular problems were significantly older than those without CVD (52.6 ± 14.6 years vs. 43.2 ±12.3 years, P <0.0001). The mean serum cholesterol and LDL concentrations were higher in the patients with CVD than in those without CVD, although the values did not reach significant levels (4.3 ± 1.0 mmol/L vs. 4.2 ± 1.03 mmol/L, P = 0.32; and 2.4 ± 0.8 mmol/L vs. 2.3 ± 0.8 mmol/L, P = 0.21, respectively). In the patients with history of CVD, the mean of serum LDL levels was significantly higher among CAPD patients compared to those on HD (3.35 ± 0.62 mmol/L vs. 2.33 ± 0.81 mmol/L, P <0.05). In patients with CVD, the mean serum cholesterol was significantly lower among HD patients (4.1 ± 0.9 mmol/L vs. 4.9 ± 1.3 mmol/L, P = 0.02). Likewise, serum LDL was significantly higher among CAPD than among HD patients (3.4 ± 0.6 mmol/L vs. 2.3 ± 0.8 mmol/ L, P <0.05). However, the mean of serum triglyceride was not significantly different between the two modalities (1.7 ± 0.9 mmol/L vs. 2.2 ± 1.2 mmol/L, P = 0.12).

The mean serum cholesterol level was significantly higher among dialysis patients who smoke compared to non-smokers (4.2 ± 1.03 mmol/L vs. 3.66 ± 0.8 mmol/L, P <0.05). Contrary to this, serum HDL concentration was significantly higher among smokers compared to non-smokers (1.0 ± 0.3 mmol/L vs. 0.9 ± 0.2 mmol/L, P <0.05). Serum triglyceride and LDL concentrations were also higher among smokers than non-smokers, though the differences did not reach significant levels (1.7 ± 0.9 mmol/L vs. 1.6 ± 0.9 mmol/L, P = 0.70; and 2.4 ± 0.9 mmol/L vs. 2.1 ± 0.7 mmol/L, P = 0.14, respectively).

A total of 98 dialysis patients were found to have hyperparathyroidism. Lipids were higher among hyperparathyroid CKD patients compared to those without hyperparathyroidism. The patients with hyperparathyroidism had significantly higher mean serum triglyceride levels compared to non-hyperparathyroid patients (1.9 ± 1.2 mmol/L vs. 1.6 ± 0.9 mmol/L, P < 0.05). Serum HDL and serum LDL levels were not significantly different between hyperparathyroids and non-hyperparathyroid patients.


   Discussion Top


In contrast to the previous studies, [16],[22] lipids increased with age and more dramatically at age greater than 60 years and in dialysis patients. Our study shows that younger people had more disturbed lipid profile when they were on CAPD. Female patients had higher cholesterol, triglycerides, and LDL levels than male patients. Factors such as hormones and individual's capability to degrade excess lipids may play a role.

In our study, however, the length of dialysis was associated with increases in the serum levels of proatherogenic lipids. The fluctuations in lipid levels observed in our study population showed a trend of increase in the total cholesterol and triglyceride serum levels as early as six months and a greater increment in the ensuing years. A short period of follow-up of patients may not reveal such trends.

The patients on maintenance HD and CAPD revealed numerous disturbances of serum lipids that may contribute to their high cardiovascular mortality. About 61% of HD patients require treatment for non-HDL cholesterol, [16] and it is even higher in CAPD patients. [6],[16],[19] The proatherogenic lipoprotein profile of CAPD patients is characterized by increased concentrations of cholesterol-rich and triglyceride-rich lipoproteins. [16] Our study shows that CAPD patients manifested more disturbed lipid profile than those on HD.

Our study shows that diabetic patients on HD had significantly higher triglycerides than non-diabetics, and similar profile was evident with diabetics on CAPD versus non-diabetics. However, the type of dialysis may still have an important role in the lipid profile alterations, since all CAPD patients had higher LDL and cholesterol levels than the HD patients.

Hypertension to some extent affected the lipid profiles of our patients. Hypertensive dialysis patients were more dyslipidemic than the normotensives, especially those on CAPD. Although our results suggest a probability that the mode of dialysis may have a greater impact on the lipid profile in these patients even in the presence of hypertension, the argument still needs to be verified.

Non-smokers had a better lipid profile compared to smokers. Nicotine increases the presence of protein in the urine and accelerates renal injury and eventually may cause ESRD requiring dialysis. This is through increasing glomerular pressure that leads to the presence of proteinuria; its role is not well understood and thought to be through various hormones or mediators including angiotensin II and nitric oxide [21],[22] according to gender.

Hypertension, diabetes mellitus, smoking and dyslipidemia, and the factors that promote CVD in the general population are particularly likely to do so in patients with ESRD because of their high prevalence in this population. [18] Our study shows that the mode of dialysis is an important factor in the progression of these patients to CVD. Nevertheless, the various factors that brought about these alterations in lipid profiles, especially among CAPD patients, have to be investigated further.

We conclude that dyslipidemia, which increases the risk of CVD by increasing atherogenesis, progresses over time in dialysis patients and becomes worse in CAPD patients.

 
   References Top

1.Kannel WB. Risk stratification of dyslipidemia: insights from the Framingham study. Curr Med Chem Cardiovasc Hematol Agents 2005;3(3): 187-93.  Back to cited text no. 1
    
2.Kannel WB, Giordano M. Long-term cardiovascular risk with protease inhibitors and management of dyslipidemia. Am J Cardiol 2004; 94(7):901-6  Back to cited text no. 2
    
3.Shoji T, Ishimura E, Inaba M, Tabata T, Nishizawa Y. Atherogenic lipoproteins in endstage renal disease. Am J Kidney Dis 2001;38 (4 Suppl 1):S30-3 .  Back to cited text no. 3
    
4.Ma KW, Greene EL, Raij L. Cardiovascular risk factors in chronic renal failure and hemodialysis populations. Am J Kidney Dis 1992;19 (6):505-13.  Back to cited text no. 4
    
5.Attman PO, Samuelson O, Johansson AC, Moberly JB, Alaupovic P. Dialysis modalities and dyslipidemia. Kidney Int Suppl 2003;84: S110-2 Review.  Back to cited text no. 5
    
6.Appel GB, Appel SA. Dyslipidemia in chronic kidney disease and end-stage renal disease: A review. Dialysis and Transp 2004;33(11):714-9.  Back to cited text no. 6
    
7.Prichard S. Risk factors for Coronary Artery Disease in patients with renal failure. Am J Med Sci 2003;325(4):209-13.  Back to cited text no. 7
    
8.McCullough PA. Cardiovascular disease in chronic kidney disease from a cardiologist's perspective. Curr Opin Nephrol Hypertens 2004;13(6):591-600.  Back to cited text no. 8
    
9.Kalantar-Zadeh K, Block G, Humpreys MH, Kopple JD. Reverse epidemiology of cardiovascular risk factors in maintenance dialysis patients. Kidney Int 2003;63(3):793-808.  Back to cited text no. 9
    
10.Sahadevan M, Kasiske BL. Hyperlipidemia in kidney disease: Causes and consequences. Curr Opin Nephrol Hypertens 2002;11:323-9.  Back to cited text no. 10
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11.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(1):37-45.  Back to cited text no. 11
    
12.Cheng SC, Chu TS, Huang KY, et al. Association of hypertriglyceridemia and insulin resistance in uremic patients undergoing CAPD. Perit Dial Int 2001;21(3):282-9.  Back to cited text no. 12
    
13.Avram MM, Antignani A, Goldwasser P, et al. Lipids in diabetic and non-diabetic hemodialysis and CAPD patients. ASAIO Trans 1988; 34:314-6.  Back to cited text no. 13
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14.Avram MM, Goldwasser P, Burrell DE, Antignani A, Fein PA, Mittman N. The uremic dyslipidemia: a cross-sectional and longitudinal study. Am J Kidney Dis 1992;240(4): 324-35.  Back to cited text no. 14
    
15.Keane WF. The role of lipids in renal disease: future challenges. Kidney Int Suppl 2000;75: S27-31.  Back to cited text no. 15
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16.Siamopoulos KC, Elisaf M. Is CAPD atherogenic? Perit Dial Int 1997;17(3):227-31.  Back to cited text no. 16
    
17.Bakkaloglu SA, Ekim M, Tumer N, Soylu K. The effect of CAPD on the lipid profile of pediatric patients. Perit Dial Int 2000;20(5): 568-71.  Back to cited text no. 17
    
18.Iseki K, Tozawa M, Takishita S. Effect of duration of dialysis on survival in a cohort of chronic haemodialysis patients. Nephrol Dial Transp 2003;18:782-7.  Back to cited text no. 18
    
19.Dejanova B, Filipee V, Dejanov P, Sikole A, Grozdanovski R, Maleska V. Atherosclerosis risk factors related to hemodialysis duration and erythropoietin therapy. Clin Chem Lab Med 2001;39(6):484-6.  Back to cited text no. 19
    
20.Kronenberg F, Lingenhel A, Neyer U, et al. Prevalence of dyslipidemic risk factors in hemodialysis and CAPD patients. Kidney Int Suppl 2003;84:S113-6.  Back to cited text no. 20
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21.Collins AJ, Li S, Ma JZ, Herzog C. Cardiovascular disease in end-stage renal disease patients. Am J Kidney Dis 2001;38:S26-9  Back to cited text no. 21
    
22.National Kidney Foundation. K/DOQI Clinical Practice Guidelines for Managing Dyslipidemias in Chronic Kidney Disease. Am J Kidney Dis 2003;41(4,Suppl 3):S39-58.  Back to cited text no. 22
    

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Correspondence Address:
Ahmed H Mitwalli
Department of Medicine, King Khalid University Hospital, P.O. Box 2925, Riyadh 11461
Kingdom of Saudi Arabia
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PMID: 21743212

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