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Saudi Journal of Kidney Diseases and Transplantation
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ORIGINAL ARTICLE Table of Contents   
Year : 2005  |  Volume : 16  |  Issue : 3  |  Page : 288-292
Correlation of Serum Parathormone with Hypertension in Chronic Renal Failure Patients Treated with Hemodialysis


1 Department of Biochemistry, The Center of Research and Reference Laboratory of Iran, Hospital Bu Ali, Damavand st.Tehran, Iran
2 Internist and Nephrologist, Shahrekord University of Medical sciences, Hajar Medical, Educational and Therapeutic Center, Section of Hemodialysis, Shahrekord, Iran

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   Abstract 

To consider the correlation of serum parathormone on severity of hypertension in end­stage renal disesase (ESRD) patients on hemodialysis (HD). A cross-sectional study was done on patients with ESRD on treatment with maintenance HD. Levels of serum calcium, phosphorus, alkaline phosphatase, albumin and intact parathormone (iPTH) were measured. Stratification of hypertensive patients was done from stages one to three. The total number of patients studied was 73 (Females=28, Males=45), consisting of 58 non-diabetic (F=22 M=36) and 15 diabetic patients (F=6 M=9). The mean age of the study patients was 46.5 ± 16 years.The mean duration on HD of the study patients was 21.5 ± 23.5 months. The mean serum PTH of the study patients was 309 ± 349 pg/ml and the mean serum alkaline phosphatase was 413 ± 348 IU/L. There was a significant positive correlation between the stage of hypertension and serum PTH levels (r =0.200 p=0.045). Also, there was a significant positive correlation between stage of hypertension and calcium-phosphorus product (r = 0. 231 p=0.027).There was no significant correlation between stage of hypertension and serum ALP (r =0.135 p=0.128). Relationship between serum PTH and severity of hypertension in patients on HD needs to be studied in more detail. Hypertention and secondary hyperparathyroidism interact in the process of accelerated atherosclerosis in HD patients thus warranting appropriate measures to control hyperparathyroidism vigorously.

Keywords: Hemodialysis, Secondary hyperparathyroidism, Hypertension, Parathormone

How to cite this article:
Baradaran A, Nasri H. Correlation of Serum Parathormone with Hypertension in Chronic Renal Failure Patients Treated with Hemodialysis. Saudi J Kidney Dis Transpl 2005;16:288-92

How to cite this URL:
Baradaran A, Nasri H. Correlation of Serum Parathormone with Hypertension in Chronic Renal Failure Patients Treated with Hemodialysis. Saudi J Kidney Dis Transpl [serial online] 2005 [cited 2019 Nov 12];16:288-92. Available from: http://www.sjkdt.org/text.asp?2005/16/3/288/32856

   Introduction Top


The pathogenesis of hypertension (HTN) in hemodialyzed uremic patients is multifactorial. It includes the following: sodium and water retention as a result of the impaired excretory capacity of the kidneys, excessively increased activity of the renin-angiotensin-aldostrone system and sympathetic nervous system, in­creased levels of the vasoconstrictor endothelin­1, accumulation of endogenous inhibitors of nitric oxide (NO) synthesis and reduced formation of vasodepressor factors. [1],[2] The prevalence of hypertension in patients with chronic renal insufficiency is high, being 60% in early stage of renal insufficiency while in terminal renal failure, it is as high as 90%. After the initiation of dialysis treatment, it declines temporarily, and again goes up in chronic HD patients (50-80%). [3] Hypertension is one of the main risk factors for cardiovascular morbidity and mortality in the general population, which are more prevalent in patients on dialysis than in the non-uremic population. [4] Cardiovascular diseases constitute a major cause of mortality in patients on HD, although epidemiological studies are controversial in this regard. [5] Another factor in the development of hyper­tension in uremic patients is raised intra­cellular calcium, which is a consequence of hyperparathyroidism. [1] Since both hypertension and secondary hyperparathyroidism (HPTH) are common features of the uremic syndrome, it has been suggested that the latter may play a role in the pathogenesis of hypertension in patients with end-stage renal disease (ESRD). [6] However, whether HPTH causes the hyper­tension is questionable, and the nature of the mechanism is unknown. Parathyroid hormone (PTH) functions to maintain calcium (Ca) levels in the blood and its release is stimulated by low Ca levels in the blood; PTH leads to vitamin D activation, increased Ca absorption in the gut, increased bone resorption, increased Ca reabsorption in the kidney and increased phospate (P) excretion in the urine. The net result of PTH activity is an increase in blood Ca level without an increase in the level of PO4. Hypertension could be caused by an increase in total peripheral resistance or an increase in blood volume. PTH can cause hypertension by increasing either of these two factors. [7] It has been shown that, when administered acutely, PTH causes a hypotensive response as a result of arterial smooth musle relaxation. [8] In patients exposed to chronically elevated PTH levels however, it has exactly the opposite effect and leads to sustained hyper­tension. [9] Reports exist suggesting a possible role for PTH in the genesis of hypertension in patients with primary or secondary hyper­parathyroidism. [10] However, there is little infor­mation on the effects of PTH on hypertension in patients undergoing regular HD. We there­fore, studied the effect of serum PTH on the severity of hypertension in patients with ESRD on HD.


   Patients and Methods Top


This is a cross-sectional study that was done on patients with ESRD undergoing mainte­nance HD treatment. Factors that served as exclusion criteria were cigarette smoking and body mass index (BMI) more than 25. All the study patients were on treatment for HPTH with oral active vitaminD3 (Rocaltrol) and calcium carbonate, both administered in appro­priate doses. The levels of serum Ca, P, alkaline phosphatase (ALP) and albumin were measured with standard kits while intact PTH (iPTH) was measured by RIA with DSL-8000 kits of USA. We stratified hypertensive patients from stage one to three, [11],[12] according to the sixth and seventh report of the joint national committee on prevention, detection, evaluation and treatment of high blood pressure. For statistical analysis, descriptive data are ex­pressed as Mean ± SD and as frequency distri­butions. Comparison between two groups was performed by using T test. For correlations, we used Spearmann`s rho and partial correlation test after adjustment for age, duration of HD treatment and also serum albumin. All statistical analysis were performed using the SPSS (version 11.00). Statistical significance was inferred at a p value < 0.05.


   Results Top


The total number of patients studied was 73 (Males = 45, Females = 28). They comprised of 58 non-diabetic (F = 22, M = 36), and 15 diabetic HD patients (F = 6, M = 9). [Table - 1] and [Table - 2] show the mean ± SD of age, the duration for which the patients had been on HD and the results of the laboratory tests. [Table - 3] shows the frequency distribution of stages of HTN. The mean serum PTH of complete patient group was 309 ± 349 pg/ml; it was 234 ± 265 pg/ml and 329 ± 368 pg/ml in the diabetic and non-diabetic groups respectively. Serum alkaline phosphatase of total patients was 413±348 IU/L. Forty percent of total patients had hypertension in stage two and 19% had HTN in stage three. There was no significant difference in the age of the patients, duration of HD treatment, serum ALP and serum PTH between the diabetic and non diabetic patients. Significant difference in the Ca x P products was found between the diabetic and non-diabetic groups (46 ± 19 versus 61 ± 24 respectively) (p=0.037). Significant positive correlation was seen between serum PTH and serum ALP (r = 0. 302, p=0.005). Also, there was significant positive correlation between the stages of hypertension and serum PTH (r=0.200, p=0.045). Significant positive corre­lation was also noticed between stages of hypertension and the Ca x P products (r = 0.231, p=0.027). There was no significant correlation between the stages of hyper­tension and serum ALP (r =0.135, p=0.128)


   Discussion Top


In this study, the principal finding was a positive correlation between serum PTH and HTN. Salem, in a cross-sectional study, of a random sample of 612 HD patients from 10 dialysis centers, examined the serum PTH and calcium levels. It was found that 25% of patients had serum PTH levels within the normal range, 25% had a PTH higher than normal (but less than three times normal), and 50% had PTH levels higher than three times the normal value. Also, diabetic patients had a lower PTH levels non-diabetic patients. The results of this study suggests that hyperpara­thyroidism is highly prevalent in the HD population. [13] Owda et al. evaluated 122 patients on maintenance HD for at least 12 months in two dialysis centers in mid-Michigan. Seventy­eight percent of his patients had PTH above 200 pg/mL (mean 481 pg/mL), 19% had PTH within the accepted normal range (mean 155 pg/mL), while 3% had levels below 100 (mean 53 pg/mL). Phosphate, calcium, calcium-phos­phate product, age and duration on dialysis were the important factors correlating with elevated PTH. There was no significant difference in PTH levels between diabetic and non-diabetic patients in his study. [14] Pizzarelli et al. tried to assess whether parathyroidectomy (PTx) affects blood pressure (BP) in HD patients. They studied 11 patients on HD treat­ment for 8.2 +/- 0.9 years who underwent successful PTx and compared them with a control group of 11 HD patients not submitted to PTx. He found that PTx causes a fall in BP in HD patients. [15] Coen et al. evaluated the long-term results of PTX on parathyroid function and blood pressure. Data of 45 patients on dialysis, with secondary hyperparathyroidism, who had undergone PTx were collected retro­spectively from eight different dialysis units. They found that 20 of 45 patients with pre­operative hypertension experienced a stati­stically and clinically significant decrease in blood pressure levels. [1] In contrast to these studies, Ifudu et al. compared pre-dialysis blood

pressure (BP), weight and dose of antihyper­tensive medications prescribed in 19 HD patients one month before total PTx, during the first month after PTx, and long-term (mean 16 months) in 12 patients. He did not demon­strate any significant change in either systolic or diastolic BP and concluded that PTx fails to correct hypertension in HD patients. [6]

In this study, we could show a relationship between serum PTH levels and severity of hypertension in our patiens. As secondary hyperparathyroidism and HTN are two factors involved in accelerated atherosclerosis in HD patients resulting in increased mortality, further clinical studies into this important aspect of the care of ESRD patients is needed.[16]

 
   References Top

1.Sobotova D, Zharfbin A, Svojanovsky J, Nedbalkova M. Hypertension in hemodialyzed uremic patients. Vnitr Lek 1999;45(11):641-4.  Back to cited text no. 1    
2.Horl MP, Horl WH. Hemodialysis-associated hypertension: pathophysiology and therapy. Am J Kidney Dis 2002;39(2):227-44.  Back to cited text no. 2    
3.Monhart V. Hypertension and chronic renal insufficiency--chronic kidney failure. Vnitr Lek 2003;49(5):388-94.  Back to cited text no. 3    
4.Zoccali C. Cardiovascular risk in uraemic patients-is it fully explained by classical risk factors? Nephrol Dial Transplant 2000; 15:454-7 .  Back to cited text no. 4    
5.Lopez-Gomez JM, Verde E, Perez-Garcia R. Blood pressure, left ventricular hypertrophy and long-term prognosis in hemodialysis patients. Kidney Int Suppl 1998;68:S92-8.  Back to cited text no. 5    
6.Ifudu O, Matthew JJ, Macey LJ, et al. Parathyroidectomy does not correct hyper­tension in patients on maintenance hemo­dialysis. Am J Nephrol 1998;18(1):28-34.  Back to cited text no. 6    
7.www.nymc.edu/physio/Courses/PHYS%202520/PTH%20and%20hypertension.htm  Back to cited text no. 7    
8.Hanson AS, Linas SL. Parathyroid hormone/ adenylate cyclase coupling in vascular smooth muscle cells. Hypertension 1994;23:468-75.  Back to cited text no. 8    
9.Hulter HN, Melby JC, Peterson JC, Cooke CR. Chronic continuous PTH infusion results in hypertension in normal subjects. J Clin Hypertens 1986;2:360-70.  Back to cited text no. 9    
10.Fliser D, Franek E, Fode P, et al. Subacute infusion of physiological doses of parathyroid hormone raises blood pressure in humans. Nephrol Dial Transplant 1997; 12:933-8.  Back to cited text no. 10    
11.The sixth report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. Arch Intern Med 1997;157:2413-46.  Back to cited text no. 11    
12.Chobanian AV, Bakris GL, Black HR, et al. The seventh report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. JAMA 2003;289:2560-72.  Back to cited text no. 12    
13.Salem MM. Hyperparathyroidism in hemodialysis population: a survey of 612 patients. Am J Kidney Dis 1997;29:862-5.  Back to cited text no. 13    
14.Owda A, Elhwairis H, Narra S, Towery H, Osama S. Secondary hyperparathyroidism in chronic hemodialysis patients: prevalence and race. Ren Fail 2003;25(4):595-602.  Back to cited text no. 14    
15.Pizzarelli F, Fabrizi F, Postorino M, Curatola G, Zoccali C, Maggiore Q. Para­thyroidectomy and blood pressure in hemo­dialysis patients. Nephron 1993;63(4):384-9.  Back to cited text no. 15    
16.Coen G, Calabria S, Bellinghieri G, et al. Parathyroidectomy in chronic renal failure: short- and long-term results on parathyroid function, blood pressure and anemia. Nephron 2001;88:149-55 .  Back to cited text no. 16    

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Correspondence Address:
Hamid Nasri
Shahrekord University of Medical sciences, Section of Hemodialysis, P.O. Box 88155-468, Shahrekord
Iran
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PMID: 17642794

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    Abstract
    Introduction
    Patients and Methods
    Results
    Discussion
    References
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