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Saudi Journal of Kidney Diseases and Transplantation
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RENAL DATA FROM ASIA-AFRICA  
Year : 2013  |  Volume : 24  |  Issue : 5  |  Page : 1068-1072
Epidemiological patterns of chronic kidney disease in black African elders: A retrospective study in West Africa


Internal Medicine and Nephrology Department, University Hospital of Saint-Louis, Saint-Louis, Senegal

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Date of Web Publication12-Sep-2013
 

   Abstract 

Chronic kidney disease (CKD) is frequently described in elders. This study describes the epidemiological patterns of patients ≥60 years old admitted in our department during one year. The prevalence of CKD was 10.8% (60/552). The mean age of the patients was 70.5 years (60-84 years) and the sex ratio (male:female) was 1.08. The mean serum creatinine level was 7.10 mg/dL (1.31-25.0 mg/dL) and more than two-third of the patients presented CKD stage 4-5. Causes of CKD were dominated by hypertension (30%) and diabetes (25%). Prevalence of inpatients aged 60-69 years old was higher than in those ≥80 years old but lower than that in patients aged 70-79 years. At admission, 83.3% of the patients were hypertensive, 75% were anemic and 13% presented proteinuria. The main co-morbidities associated with CKD were neoplasms (17% of cases), chronic heart disease (15% of cases) and pneumonia (15% of cases). Furosemide was prescribed in 55% of the patients, calcium channel blockers in 23% of the patients and ACE inhibitors in 20% of the patients. Renal replacement therapy was not performed for any patient. Evolution was favorable in the majority of patients (77%), but 23% died mainly because of uremia and infections.

How to cite this article:
Seck SM, Diallo IM, Diagne SI. Epidemiological patterns of chronic kidney disease in black African elders: A retrospective study in West Africa. Saudi J Kidney Dis Transpl 2013;24:1068-72

How to cite this URL:
Seck SM, Diallo IM, Diagne SI. Epidemiological patterns of chronic kidney disease in black African elders: A retrospective study in West Africa. Saudi J Kidney Dis Transpl [serial online] 2013 [cited 2019 Jul 23];24:1068-72. Available from: http://www.sjkdt.org/text.asp?2013/24/5/1068/118104

   Introduction Top


Chronic kidney disease (CKD) is a worldwide major public health problem with high morbidity and mortality rates. [1] Population-based studies have demonstrated that the prevalence of moderate to severe CKD increases with age. [2],[3] This age-related decline of renal function relies partly on structural modifications in the aging kidney [4] . In the National Health and Nutrition Examination Survey (NHANES) 1999 and 2004, the prevalence of reduced glomerular filtration rate (GFR) (<60 mL/min/1.73 m 2 ) was 37.8% among participants ≥70 years old. [5] In Africa, despite a growing number of elders, data on CKD in this population are scarce. The present study aimed to describe the epidemiological and clinical patterns of CKD among elders.


   Patients and Methods Top


We have conducted a retrospective study of 60 patients aged 60 years and older who were hospitalized between January 1 and December 31, 2010 in our internal medicine and nephrology department. For each patient, the following data were collected from their medical records: Age, sex, medical history, etiology of CKD, blood pressure, hemoglobin, serum creatinine, calcium, phosphorous, cholesterol, urinary albumin excretion, treatment, and progress of the disease after one year. Incomplete records were excluded from the study. GFR was estimated using the four-variables equation Modified Diet for Renal Disease (MDRD) study with the correction factor for black patients and CKD was defined and classified according to the National Kidney Foundation Disease Outcomes Quality Initiative (NKF-KDOQI) guidelines. [6] Hypertension was defined by blood pressure level ≥ 140/90 mmHg and anemia was considered when serum hemoglobin was lower than 11 g/dL. Statistical analysis was performed using MS Excel 2007.


   Results Top


We included 60 patients from the 552 elders who were admitted in our department during the study period (prevalence of 10.86%). Demographical, clinical and biochemical data are presented in [Table 1]. The distribution of patients according to age and gender is presented in [Figure 1]. In their medical past, 20% of the patients had been followed for hypertension, and 18% of them were known diabetics. [Figure 2] represents the distribution of different CKD stages according to age. All patients had hypocalcemia and 96.7% presented hyperphospha 18% of them were known diabetics. [Figure 2] represents the distribution of different CKD stages according to age. All patients had hypocalcemia and 96.7% presented hyperphosphatemia. Parathormone dosage was not available. Hypertension and anemia were present in 83.3% and 75% of our patients, respectively, but their prevalence did not grow proportionally to CKD stages [Figure 3]. Proteinuria (>0.5 g/L) was found in 13%. Etiologies of CKD were dominated by hypertension (30%) and diabetes (25%). The most frequent co-morbidities associated with CKD were neoplasms (17% of cases), chronic heart disease (15% of cases), pneumonia (15% of cases), dyslipidemia (10% of cases), stroke (7% of cases) and malaria (5% of cases). Antihypertensive drug therapy in our patients included furosemide (55%), calcium channel blockers (23%), ACE inhibitors (20%), beta-blockers (8%) and thiazide diuretics (5%). Treatment of anemia comprised of iron supplementation and blood transfusions because erythropoietin was not available. Evolution was favorable in 77% of the patients who were discharged and followed-up in an outpatient clinic. The mortality rate was 23% (14 patients) after one year. The main causes of deaths were: Prostate cancer (one case), malaria (two cases), severe pneumonia (two cases) and end-stage renal disease (ESRD) (nine cases). None of our patients received renal replacement therapy in our hospital as it was not available. However, six patients were sent to another center for hemodialysis treatment.
Figure 1: Distribution of patients according to age and gender.

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Figure 2: Distribution of stages of chronic kidney disease in our population.

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Figure 3: Prevalence of hypertension and anemia according to stages of chronic kidney disease.

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Table 1: Demographical, clinical and biochemical characteristics of elders with CKD.

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   Discussion Top


Epidemiological and clinical patterns of CKD are poorly described in black African elders. This study demonstrates a high prevalence of patients with eGFR lower than 60 mL/min/ 1.73 m 2 at admission in our department. The proportion of CKD stages 3-5 in our patients is very high compared with previous reports in African American elders, where 3.3% had eGFR <60 mL/min/1.73 m 2 . [7] In Conakry, Kaba et al reported a CKD prevalence of 5.5% among patients aged ≥60 years who were admitted in the emergency department. [8] In the USA, the prevalence of a serum creatinine ≥1.5 mg/dL was 21.25% in participants aged 60-69 years old and 32.26% in those aged ≥70 years. [9] Another particularity of our study is that CKD stage 5 was the most frequent presentation (60% of patients), while Bouattar et al reported a lower prevalence of ESRD (18%) in 293 diabetic patients with a mean age of 71.4 years. This high prevalence of advanced CKD stages can be explained by late diagnosis and referral. Moreover, in our black African cohort, eGFR could have been underestimated by the use of MDRD equation, leading to an abnormally high prevalence of patients with CKD stages 3-5. Nevertheless, the presence of CKD-related complications such as anemia, hypocalcemia, hyperphosphatemia and hypertension in more than two-third of our patients is compatible with effective kidney failure in most of them. In fact, interpretation of renal function in old patients is controversial. Some authors have suggested that reduced eGFR among older adults may not reflect the presence of kidney disease but a normal aging related decline of kidney function [11] , and they proposed to include age-specific cut points for staging CKD in the National Kidney Foundation Disease Outcomes Quality Initiative (NKF-KDOQI) guidelines. [12] However, in the general population, recent data have demonstrated that eGFR <60 mL/min/1.73 m 2 was associated with a higher prevalence of concurrent CKD-related complications, including anemia, acidosis, hyperphosphatemia, hypoalbuminemia, hyperparathyroidism and hypertension. [13] Prevalences of hypertension and anemia were very high in our patients (83.3% and 75%, respectively). In one study from Morocco, these complications were less frequent (81.9% of patients were hypertensives and 58.7% presented anemia) and proportional to CKD severity. [10] Our results did not find a relationship between the severity of CKD and the prevalence of hypertension or anemia.

This study presents several limitations inherent to its retrospective design, which implies the risk of missing data in the patients' medical records. Moreover, extension of results to other black Africans is limited because it is a hospital-based, small sample-size and a single-center study. However, our findings provide an insight on the burden of the CKD epidemic in black African elders. Additional prospective and multicenter studies involving patients from several African regions are needed.

In conclusion, CKD is frequent in patients ≥60 years old admitted in our department. Because of late diagnosis and referral, majority of patients are seen at stage 4-5 with severe uremic complications. Hypertension and diabetes represent the main etiologies and comorbidities are frequent. Evolution is favorable in more than 3/4 of the patients, but mortality remains high in the absence of dialysis treatment. To improve outcomes in African elders with CKD, much effort should be made on dialysis accessibility and sustainability in this part of the world.

 
   References Top

1.James MT, Hemmelgarn BR, Tonelli M. Early recognition and prevention of chronic kidney disease. Lancet 2010;375:1296-309.  Back to cited text no. 1
[PUBMED]    
2.Levey AS, Stevens LA, Schmid CH, et al. A new equation to estimate glomerular filtration rate. Ann Intern Med 2009;150:604-12.  Back to cited text no. 2
[PUBMED]    
3.James MT, Eriksen B, Ingebretsen OC. The progression of chronic kidney disease: A 10-year populationbased study of the effects of gender and age. Kidney Int 2006;69:375-82.  Back to cited text no. 3
    
4.McLachlan MS. Anatomic structural and vascular changes in the aging kidney. In: Macias Nunez JF, Cameron JS eds. Renal function and disease in the elderly. London: Butterworths; 1987. p. 3-26.  Back to cited text no. 4
    
5.Coresh J, Selvin E, Stevens LA, et al. Prevalence of chronic kidney disease in the United States. JAMA 2007;298:2038-47.  Back to cited text no. 5
[PUBMED]    
6.National Kidney Foundation-K/DOQI, Clinical Practice Guidelines for chronic kidney disease, evaluation, classification and stratification. Am J Kidney Dis 2002;39:S1-266.  Back to cited text no. 6
    
7.Manjunath G, Tighiouart H, Coresh J, et al. Level of kidney function as a risk factor for cardiovascular outcomes in the elderly. Kidney Int 2003;63:1121-9.  Back to cited text no. 7
[PUBMED]    
8.Kaba ML. Prevalence of chronic renal failure in patients aged 60 years and older admitted in emergency department: Evolution between 1997-2005. Nephrol Ther 2007;3:340-5.  Back to cited text no. 8
    
9.Jones CA, Quillan MC, Kuse KJ, et al. Serum creatinine in the US population: Third national health and nutrition examination survey. Am J Kidney Dis 1998;32:992-9.  Back to cited text no. 9
    
10.Bouattar T, Mattous M, Benasila S, et al. Kidney failure in diabetic elders. Nephrol Ther 2009;5:408.  Back to cited text no. 10
    
11.Glassock RJ, Winearls C. CKD-Fiction not fact. Nephrol Dial Transplant 2008;23:2695-6.  Back to cited text no. 11
[PUBMED]    
12.Glassock RJ, Winearls C. Screening for CKD with eGFR: Doubts and dangers. Clin J Am Soc Nephrol 2008;3:1563-8.  Back to cited text no. 12
[PUBMED]    
13.Inker LA, Coresh J, Levey AS, Tonelli M, Muntner M. Estimated GFR, albuminuria, and complications of chronic kidney disease. J Am Soc Nephrol 2011;22(12):2322-31.  Back to cited text no. 13
    

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Correspondence Address:
Sidy Mohamed Seck
Health Sciences Department, University Gaston Berger of Saint-Louis, Route de Ngallèle, BP: 234, Saint-Louis
Senegal
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DOI: 10.4103/1319-2442.118104

PMID: 24029286

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