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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 : 3  |  Page : 456-463
Prevalence of anemia in predialysis chronic kidney disease patients


1 Saudi Center for Organ Transplantation, Riyadh, Saudi Arabia
2 Kanoo Kidney Center, Dammam, Saudi Arabia
3 Alnoor Specialist Hospital, Makkah, Saudi Arabia
4 King Fahd Hospital, Jeddah, Saudi Arabia
5 King Fahd Hospital, Al Baha, Saudi Arabia
6 King Fahd Hospital, Gizan, Saudi Arabia
7 King Fahd Hospital, Hofuf, Saudi Arabia
8 Assir Central Hospital, Saudi Arabia
9 King Fahd Specialist Hospital, Al Qassim, Saudi Arabia
10 King Fahad Hospital, Madina, Saudi Arabia
11 Buraida Central Hospital, Saudi Arabia
12 King Khaled Hospital, Hail, Saudi Arabia

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Date of Web Publication7-May-2011
 

   Abstract 

To evaluate the prevalence of anemia in a large cohort that comprises patients in different stages of chronic kidney disease (CKD) in the kingdom of Saudi Arabia (KSA), we conducted a multi-center cross-sectional study of a cohort of CKD patients who have not started dialysis. The study patients were recruited from the nephrology clinics in 11 different medical centers distributed all over the regions of the KSA. For the estimated glomerular filtration rate (GFR), we used the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation. There were 250 study patients who fulfilled the criteria for the study. The patients were stratified according to their GFR as follows: stage 1: 19 patients, stage 2: 35 patients, stage 3: 67 patients, stage 4: 68 patients, and stage 5: 61 patients. The composite of proteinuria and abnormal imaging in stages 1 and 2 was satisfied in 100% of the cases. The prevalence of anemia was elevated for the hemoglobin levels below 12 g/dL (the level at which the evaluation of anemia in CKD should be initiated) in the different stages of CKD, that is, 42%, 33%, 48%, 71%, and 82% in the stages from 1 to 5, respectively. The prevalence was also elevated for the hemoglobin levels below 11 g/dL (the minimum hemoglobin level at which therapy should be initiated with erythropoietin), that is, 21%, 17%, 31%, 49%, and 72%, respectively for stages from 1 to 5. In conclusion, we found a large prevalence of anemia among the CKD population in Saudi Arabia, and the burden of patients who require treatment with erythropoietin is considerably large. However, the response to therapy will not require large doses according to the availability of long-acting erythropoiesis stimulating agents, which will render the therapy more convenient and less expensive.

How to cite this article:
Shaheen F, Souqiyyeh MZ, Al-Attar BA, Karkar A, Al Jazairi AM, Badawi LS, Ballut OM, Hakami AH, Naguib M, Al-homrany MA, Barhamein MY, Ahmed AM, Khardaji MM, Said SA. Prevalence of anemia in predialysis chronic kidney disease patients. Saudi J Kidney Dis Transpl 2011;22:456-63

How to cite this URL:
Shaheen F, Souqiyyeh MZ, Al-Attar BA, Karkar A, Al Jazairi AM, Badawi LS, Ballut OM, Hakami AH, Naguib M, Al-homrany MA, Barhamein MY, Ahmed AM, Khardaji MM, Said SA. Prevalence of anemia in predialysis chronic kidney disease patients. Saudi J Kidney Dis Transpl [serial online] 2011 [cited 2019 May 19];22:456-63. Available from: http://www.sjkdt.org/text.asp?2011/22/3/456/80480

   Introduction Top


The chronic kidney disease (CKD) population is much larger than the dialysis population. [1] There is an increase in the prevalence of anemia among CKD patients with the progression of the disease. [2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12] Furthermore, there is an associated increase of morbidity in the pre-dialysis CKD population because of the prevalent anemia [8],[13],[14] with increased risk of cardiovascular [14],[15],[16],[17],[18],[19],[20],[21],[22],[23] and cerebrovascular events, [24] in addition to increased tendency for progression of CKD, [25],[26] and hospitalizations. [19],[20],[25],[27],[28] Finally, there is an increased all cause mortality among the anemic CKD patients. [29],[30],[31],[32]

However, there has been an improvement in the parameters of morbidity in the CKD patients with the treatment of anemia, in terms of quality of life and decreased hospitalizations. [23],[27],[31],[33],[34],[35]

The aim of this study was to evaluate the prevalence of anemia in a large cohort that comprises patients in different stages of CKD in the KSA. In addition, we compared the prevalence of comorbidity and causes of kidney disease with the prevalence of anemia.


   Patients and Methods Top


This was a multicenter study of a cohort of CKD patients who had not started dialysis. The study patients were recruited from the nephrology clinics in 11 different medical centers distributed over all the regions of the KSA (Buraida Central Hospital; King Fahd Specialist Hospital, Qassim; King Fahd Hospital, Jeddah; Al Noor Specialist Hospital, Makkah; Kanoo Kidney Center - Dammam Medical Complex; King Fahd Hospital, Hofuf; King Fahd Hospital, Al Baha; King Fahd Hospital, Gizan; Assir Central Hospital; King Fahd Hospital, Madinah; and King Khalid Hospital, Hail).

This was a cross-sectional case-population study. The consultant nephrologists in the participating centers filled the data in a file prepared by the investigators at the Saudi Center for Organ Transplantation (SCOT). The data in the files were entered in a database and analyzed by a biostatistician at the SCOT.

We included in the study predialysis CKD patients of age ranging from 18 to 75 years, staged according to their current estimated glomerular filtration rate (GFR), and who did not receive erythropoietin therapy or hematinics (B 12 , folate or iron) or androgens at the time of evaluation, with no obvious bleeding episodes or causes of anemia other than CKD (i.e. hemolysis) and were not transfused over the previous 8 weeks, for the evaluation of the hemoglobin levels. We excluded smokers, pregnant women and patients with chronic infections, malignancy, and severe cardiac and pulmonary disease.

The patients' files covered the demographic data, causes of kidney disease, the causes of anemia, review of systems and co-morbidities, past medical history including hospitalizations, current medications, and physical examination. The laboratory investigations included serum creatinine, estimated GFR, urinalysis, proteinuria/creatinine ratio, ultrasound of the kidneys, other imaging of the kidneys if available, a kidney biopsy if indicated or available, complete blood count (CBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) if available, glucose, iron studies [ferritin, total iron binding capacity (TIBC), iron binding capacity (IBC), and saturation ratio], parathormone (PTH), calcium (Ca), phosphate (P0 4 ), and lipid profile. The current medications were also recorded in all the patients. Consents for the study were obtained from all the patients.

For the estimated GFR, we used the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation, which is preferred for the purpose of the study. [36]

CKD-EPI estimated GFR (eGFR) = 141 × min (SCr mg/dL)/κ, 1)α × max (SCr/ κ, 1) -1 .209 × 0.993 age × 1.018 (if female) × 1.159 (if Black), where SCr is serum creatinine, κ is 0.7 for females and 0.9 for males, α is -0.329 for females and -0.411 for males, min indicates the minimum of SCr/ κ or 1, and max indicates the maximum of SCr/ κ or 1.

In order to study the prevalence of the anemia in the CKD study patients, we stratified them according to their eGFRs into five stages according to the K/DOQI initiative [1] as follows: stage 1: eGFR above 90 mL/min/1.73 m 2 with proteinuria and/or abnormal imaging of the kidneys; stage 2: eGFR 60-90 mL/min/1.73 m 2 with proteinuria and/or abnormal imaging of the kidneys; stage 3: eGFR 30-59 mL/min/ 1.73 m 2 ); stage 4: eGFR 15-29 mL/min/1.73 m 2 ; and stage 5: eGFR: <15 mL/min/1.73 m 2 .


   Statistical Analysis Top


The statistical software, SPSS, version 13.0, was used throughout the analysis to obtain the descriptive statistics (mean, std., etc) and to summarize the data into frequency tables and percentages. For comparison, the independent samples t-test was used to test the significance for the continuous variables and the non-parametric Chi-square test was used for the non-continuous variables. The test result is held significant if P < 0.05.

All the data were compiled descriptively in tables and frequencies. The analysis of the data addressed the validity of the answers in connection with key questions in the patients' files and end-points.

Pearson's Chi-square test was used throughout the analysis to test the significance of differences between groups and sub-groups for the noncontinuous variables, while the Student's " t" test was used for the comparison of the means of the continuous variables. Statistical significance was set at P < 0.05.


   Results Top


There were 250 study patients who fulfilled the criteria for the study and this included 136 males (54.4%), and the mean age was 51.6 ± 15.8 years. There were 227 (94.6%) Saudi patients, and the mean duration of the disease was 8.2 ± 7.4 years. There were 105 (42%) diabetic patients.

The patients were stratified according to their GFR: stage 1: 19 patients, stage 2: 35 patients, stage 3: 67 patients, stage 4: 68 patients, and stage 5: 61 patients. The composite of proteinuria and abnormal imaging in stages 1 and 2 was satisfied in 100% of the cases.

[Table 1] summarizes the parameters of the study patients according to the stages of eGFR. Diabetics increase in percentage with advancement of the CKD, and so is the mean of parathormone. The ferritin levels and iron saturation were within the normal levels in all the stages of the CKD.
Table 1: Summary of the parameters of the study patients (total 250) according to the stages of estimated glomerular filtration rate (eGFR).

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[Figure 1] shows the prevalence of anemia in the different stages of CKD. The prevalence was elevated for the hemoglobin levels below 12 g/dL (the level at which the evaluation of anemia in CKD should be initiated) in the different stages of CKD, that is, 42%, 33%, 48%, 71%, and 82% in the stages from 1 to 5, respectively. The prevalence was also elevated for the hemoglobin levels below 11 g/L (the minimum hemoglobin levels at which therapy should be initiated with erythropoietin), that is, 21%, 17%, 31%, 49%, and 72%, respectively, for stages 1-5.
Figure 1: The distribution of patients according to their hemoglobin levels in the different stages of the
estimated glomerular filtration rate (GFR).


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[Figure 2] shows the prevalence differences between males and females. The prevalence of the hemoglobin levels below 12 g/dL for females and males (the level at which the anemia work-up should be started) was 72% and 50%, respectively. The prevalence of the hemoglobin levels below 11 g/dL for females and males (the level at which the anemia therapy with erythropoietin should be started) was 51% and 36%, respectively.
Figure 2: The distribution of the prevalent levels of hemoglobin in the study patients according to gender.

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[Table 2] shows the correlation between the parameters and severity of anemia in the study patients. In comparison with the group with the hemoglobin levels above 12 g/dL, the group with hemoglobin below 10 g/dL had more prevalence of diabetes, history of transfusions, hospitalizations, female gender, and mean parathormone levels, but less prevalence of treatment with angiotensin converting enzyme inhibitors (ACEIs) and angiotensin receptor blocking agents (ARB)s.
Table 2: The correlation between the parameters and severity of anemia in the study patients.

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The correlation between the presence of diabetes mellitus (DM) and the mean hemoglobin levels shows a significantly lesser level in the diabetics than non-diabetics (11.3 ± 1.87 and 11.9 ± 2.15 g/dL; P < 0.01). The mean parathormone levels also increased with the progression of CKD and anemia and correlated significantly with the severity of anemia (P < 0.001) [Table 2].


   Discussion Top


The results of this study demonstrate that the prevalence of anemia in the different stages of CKD is considerably elevated and for the level of hemoblobin at which the evaluation is required and the level at which anemia requires therapy with erythropoietin. The prevalence also increases as the CKD progresses.

The pattern of prevalence of anemia is comparable with that reported in other studies showing the high prevalence that increases with the advancement of CKD. Kazmi et al [2] showed in their study in Boston, USA, the prevalence of anemia below 12 g/dL to be 45%, 49%, 58%, 92%, 92% in CKD stages 1-5, respectively, and below 11 g/dL as 24%, 34%, 41%, 79%, 74%, respectively, for stages 1-5. This prevalence pattern is similar to the findings in our study, but slightly lower in ours due most likely to the difference in the population and geographic variation. [10] Furthermore, the pattern of the anemia differs between males and females; female gender is considered as a risk factor for worse anemia in CKD patients. [37] Our study found similar pattern with more females having worse anemia than males.

There are other risk factors besides gender for more severe anemia as reported in the previous studies about the prevalence of anemia in the CKD patients, including diabetes [2],[3],[4],[38] as a cause of renal failure, CKD stage, [3] serum transferrin saturation and serum ferritin levels, [4],[38] parathormone levels, [3] and ACEI or ARB therapy [3] . In our study, we found similar risk factors except the treatment with ACEIs and ARBs, which was associated with less prevalence of severe anemia.

The burden of the anemia therapy was assessed in previous studies. [37],[39] Furthermore, if we estimate the burden of CKD population with hemoglobin below 11 g/dL in the USA according to the study by Kazmi et al [2] (estimated number of all CKD patients: 13.0 million Americans), the anemic population in need of treatment with erythropoietin will be 11.8 million.

Now, if we calculate the burden of the patients in need for therapy with erythropoietin according to the estimated population of CKD in Saudi Arabia [40] (estimated CKD patients: 1- 2 million Saudis who form 5-10% of the 21 million total population), then we find that it ranges from 300,000 to 500,000 CKD patients in Saudi Arabia.

In conclusion, we found a large prevalence of anemia among the CKD population in Saudi Arabia, and the burden of patients who require treatment with erythropoietin is considerably large. However, the response to therapy will not require large doses according to the availability of long-acting erythropoiesis stimulating agents, which will render the therapy more convenient and less expensive.


   Acknowledgment Top
We are grateful to Roche pharmaceuticals for their unrestricted grant that made this study possible. *The Anemia prevalence in CKD patients group.[Additional file 1]

 
   References Top

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Correspondence Address:
FAM Shaheen
Saudi Center for Organ Transplantation, P.O. Box 27049, Riyadh
Saudi Arabia
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