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Saudi Journal of Kidney Diseases and Transplantation
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RENAL DATA FROM ASIA - AFRICA  
Year : 2014  |  Volume : 25  |  Issue : 5  |  Page : 1110-1116
Pediatric kidney diseases in an African country: Prevalence, spectrum and outcome


Department of Pediatrics, College of Medicine, University of Lagos and Lagos University Teaching Hospital, Idi-Araba, Lagos, Nigeria

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Date of Web Publication2-Sep-2014
 

   Abstract 

Insufficient data to guide the authorities responsible for resource allocation and a focus on communicable diseases increase the challenges of care of children with kidney disease in resource-constrained settings like ours. This study was performed with the aim to describe the current spectrum of pediatric nephrology disease in a tertiary hospital in Sub-Saharan Africa and highlight the challenges encountered in their care. A 4-year retrospective review of pediatric renal admissions was carried out and the overall prevalence, disease-specific prevalence and mortality rates were determined. Results were compared with nationwide data. Kidney diseases accounted for 8.9% of pediatric admissions with a prevalence of 22.3 admissions per 1000 child-admissions per year. Nephrotic syndrome, acute kidney injury and nephroblastoma accounted for almost 70% of admissions. The overall mortality was 14.4% with acute kidney injury accounting for 36% of this. Chronic kidney disease was also associated with poor outcome. The spectrum of disease nationwide is similar with a wide variation in disease-specific prevalence between geographic regions. The prevalence of genetic and hereditary conditions was low. The prevalence of pediatric renal disease in our environment is on the increase and associated with significant morbidity and mortality. Late presentation and high treatment costs were limitations to care. Preventive nephrology, training of pediatric nephrologists and strengthening of health insurance schemes are advocated.

How to cite this article:
Ladapo TA, Esezobor CI, Lesi FE. Pediatric kidney diseases in an African country: Prevalence, spectrum and outcome. Saudi J Kidney Dis Transpl 2014;25:1110-6

How to cite this URL:
Ladapo TA, Esezobor CI, Lesi FE. Pediatric kidney diseases in an African country: Prevalence, spectrum and outcome. Saudi J Kidney Dis Transpl [serial online] 2014 [cited 2017 Jun 28];25:1110-6. Available from: http://www.sjkdt.org/text.asp?2014/25/5/1110/139976

   Introduction Top


Despite the challenges of pediatric nephrology practice, [1],[2] significant success in disease out­come is being reported from developed coun­tries. This is largely attributable to available expertise, management facilities, health insu­rance schemes and screening programmes. In developed countries, proper documentation, with established renal registries often provide data to guide stakeholders in resource allocation. [3],[4] This is in contrast to what is obtainable in developing countries like ours, where low prio­rity is accorded, partly due to the focus on communicable diseases and also because of a lack of data on pediatric kidney diseases, with resultant overall poor outcome in these group of patients. [5],[6],[7],[8],[9],[10],[11],[12],[13],[14]

The burden of pediatric kidney disease in our environment is difficult to estimate as the avai­lable reports are few and far between in time frame and are mostly hospital based. Non-uniformity of study parameters and varying levels of diagnostic facilities also make deci­phering of the findings difficult. Changing eco­nomic climates, improved diagnostic facilities, increasing prevalence of conditions associated with kidney disease [14],[15] and standardization of disease definitions [16] all imply possible change in disease epidemiology. This study reviews the current spectrum of childhood kidney di­seases in our environment, highlighting the challenges of care.


   Subjects and Methods Top


Study center and population

The study was carried out at the Pediatric Nephrology Unit of a Teaching Hospital in South-Western Nigeria, one of two tertiary hospitals in the state providing pediatric nephrology care to children in the region. Peritoneal and hemodialysis services were being gra­dually scaled up during the study period follo­wing improvements in facilities and medical staffing. Dialysis is however largely acute and experience with long-term dialysis is limited. The unit does not yet offer renal transplant services. Health care is not free; thus, access to care is largely by payment for services provi­ded. A few families have access to care either via their employers' health schemes or through the recently established Nigerian National Health Insurance scheme, which is still limited in coverage.

Data collection

Data on all children admitted over a four-year period (2008-2011) were retrospectively ana­lyzed. This included the demographic data, cli­nical history, investigations, diagnosis, disease outcome and procedures such as dialysis and renal biopsies. Inclusion criteria were age one month to 17 years, neonates with congenital anomalies of the kidney and urinary tract (CAKUT) and ward admission. AKI was diag­nosed using the RIFLE (Risk, Injury, Failure, Loss, End-stage) criteria. [16] Chronic kidney di­sease (CKD) and nephrotic syndrome were defined based on the Kidney Disease Out­comes Qualitative Initiative (KDOQI) [17] and the International Study of Kidney Disease in Children guidelines [18] respectively. Diagnosis was based on history, physical examination and laboratory investigations such as urinalysis, urine microscopy blood chemistry, hematologic, immunologic and histopathologic studies. Imaging techniques such as ultrasonography, micturating cystourethrogram, intravenous urogram, computerized tomography and magnetic resonance imaging were also employed. Ethical approval for the study was obtained from the Health Research and Ethics Committee of the hospital.

Data analysis

Data was analyzed using the Statistical Package for Social Science software version 17. Continuous data were represented as mean or median as appropriate while categorical data were presented as percentages. The prevalence of pediatric renal disease was calculated as the proportion of the total number of pediatric admissions diagnosed with a renal condition. Mortality rate was calculated as a proportion of the total number of deaths. Comparison with previous similar studies from the country was done.


   Results Top


Of the 3594 pediatric ward admissions, kidney diseases accounted for 320 admissions in 291 children, accounting for 8.9% of all admissions with a prevalence of 22.3 admissions per 1000 child-admissions per year. There were 209 males and 111 females (M:F-1.9:1), with age range 0.3-180 ( median 48 months). [Figure 1] shows a gradual rise in pediatric renal admis­sions from 5.5% of all admissions in 2008 to 12.6% of all admissions in 2011. The spectrum of kidney diseases seen is shown in [Table 1]. The majority (82.3%) were acquired. Nephrotic syndrome, nephroblastoma and AKI accounted for almost 70% of the cases. The most common cause of AKI was septicemia, often in association with diarrhea. It was asso­ciated with other renal conditions in 35 chil­dren, 24 of whom had acute post-streptococcal glomerulonephritis (AGN). Three cases were secondary to ethylene glycol poisoning all of whom died. AKI was the presentation in 72.2% of the AGN cases.
Figure 1: Pediatric renal admissions over the study period.

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Table 1: Spectrum of pediatric kidney disease among 320 admissions.

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Of the 56 cases of CAKUT, posterior urethral valves (PUV) was the most common (38; 67.9%); the others were pelvi-ureteric junction obstruction (PUJ) (7; 12.5%), vesico-ureteric junction obstruction (1;1.8%), meatal stenosis (6; 10.7%A), neuropathic bladder (2;3.6%) and prunebelly syndrome (1;1.8%). One child was discharged against medical advice prior to definitive diagnosis. Fourteen of the children with Urinary Tract Iinfection (UTI) had back­ground CAKUT. Twenty (6.25%) children were diagnosed with CKD, six (30%) of whom were already in end-stage kidney disease (ESKD). Etiology is as follows: Posterior urethral valves (5; 25%), nephrotic syndrome (5; 25%), one of which was associated with cyanotic congenital heart disease in a Down's syndrome patient while one was infantile; lupus nephritis (3;15%), one case each due to neuropathic bladder secondary to meningomyelocoele, bila­teral nephroblastoma, bilateral PUJ obstruction and HIV-related kidney disease. Etiology was unknown in three cases.

Outcome

There were 42 deaths, giving a mortality rate of 14.4%. Mortality rate by diagnosis is shown in [Table 1]. Dialysis was carried out in 70% of all children who required it acutely. Causes of death from CKD were as follows: Bilateral renal vein thrombosis in a child with infantile, steroid-resistant nephrotic syndrome; cerebrovascular accidents following hypertensive encephalopathy in two children with nephrotic syn­drome, one of whom was on hemodialysis; two cases of lupus nephritis, one of which was from overwhelming septicemia secondary to central line sepsis; HIV-associated nephropathy (HIVAN) in one patient. Two of the children with ESKD were transplanted at other centers, while four died. Three children with non end stage CKD were lost to follow-up, while the rest were being followed up in the out-patient clinic.

Comparative analysis

A comparative analysis with a previous study carried out in our center is shown in [Table 2]. This shows a significant increase in admission rates for all diagnoses, especially for nephrotic syndrome, nephroblastoma and UTI. No cases of lupus nephritis or HIVAN were repor­ted in the previous study. In comparison with other Nigerian studies [Table 3], nephrotic syndrome was the leading diagnosis in most centers, followed by AGN. A high prevalence of AKI, as in our study, was only reported from Jos. [12] The prevalence of nephroblastoma in Lagos was three- to four-fold that reported from other parts of the country. There was a wide variation in the number of pediatric nephrology cases seen across centers.
Table 2: Comparison of the current study with a previous study of paediatric renal admissions in the same hospital.

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Table 3: A comparison of the spectrum of pediatric kidney disease among Nigerian studies.

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   Discussion Top


The findings of this study demonstrate an in­creasing prevalence of childhood kidney disea­ses in our environment. The prevalence of 8.9% for kidney disease among hospital admissions is higher than that from previous reports from other parts of the country, which range from 1.1-4.5%. [9],[11],[12],[13] Prevalence had also doubled over the study duration. This is likely to be a consequence of newer diagnostic tools, stan­dardization of disease definitions, [16] improved access to dialysis and increased manpower in the renal unit, rather than solely a true rise in prevalence. In addition to this is the emergence of the role of diseases like HIV in kidney pathology. [14] Previous studies, similar to ours were however largely tertiary hospital-based; hence, unlikely to be representative of the actual burden of the disease in the community.

Recent data on the overall prevalence of pediatric renal disease from other African countries is scarce. This may be indicative of poor disease characterization, consequent upon relative under-development of the sub-specialty in the region. A study from Libya about two decades ago [19] reported a prevalence of 3% among pediatric admissions, while more recently a prevalence of 12% was reported among pediatric admissions in India. [20] Data from countries such as the United Kingdom [3] and America [21] are largely centered around chronic kidney disease, presumably due to significant advancements in the provision of renal replacement therapy (RRT). I addition, the prevalence of conditions such as sepsis and diarrhea that contribute to AKI in children in the developing world is low in these regions.

Nationwide, the disease spectrum was sim­ilar, although wide variations in disease fre­quency existed. This may be a reflection of the role of factors such as of the environment, diet and climate on kidney disease. Varying levels of expertise and diagnostic facilities may how­ever also be contributory. Nephrotic syndrome was our leading diagnosis, similar to reports from most other parts of the country, [7],[8],[9],[11] with the exception of that from Port Harcourt, [13] which was over a decade ago, and more recently, Jos. [12] The reasons for this are not clear and may reflect the interplay of various factors in the etiopathogenesis of NS. This predominance of NS has also been observed in various regions of the world. [19],[20] The high prevalence of post-infectious AGN, similar to other reports from the country [11],[12],[13] as well as from India, [20] mirrors the high prevalence of infectious diseases in these regions. This emphasizes the role of control of infectious diseases as a strategy for reduction of the burden of pediatric renal diseases.

We are of the opinion that the higher preva­lence of AKI documented in comparison with previous reports resulted from increased dia­lysis access as well as use of the RIFLE criteria, [16] which enables the inclusion of earlier stages of AKI. Mortality rate was however still high and is a source of concern. Late presen­tation, poor urine monitoring and inadequate intensive care facilities for monitoring of critically ill children were all contributory to this. Mortality would therefore presumably be much higher in peripheral hospitals, where facilities and expertise for dialysis are lacking. The role of the underlying disease in mortality is highlighted by the 100% case fatality rate among the AKI cases secondary to ethylene glycol poisoning in the later part of 2008 at our center. [22]

A study from our center [9] over a decade ago similarly reported a higher prevalence of nephroblastoma compared with other regions of the country, [11],[12],[13] similar to our current findings. The reasons for this remain unclear and cons­titute room for future research. The prevalence of UTI in this study is low. According to a recent meta-analysis, the prevalence of child­hood UTI's ranges between 7% and 7.8%. [23] Studies included were however largely from the developed world; hence, the findings may not be applicable in our setting. The prevalence obtained in this study is likely to be an under-estimation resulting from inadequate screening and low micro-organism yield from cultures due to previous antibiotic use. Poste­rior urethral valves was the leading CAKUT similar to local and global reports. [2],[4],[10],[11],[12],[13] This was characterized by late presentation and low rates of antenatal detection, in contrast to what is obtained in the developed world. [24] It is therefore not surprising that CAKUT was the leading cause of CKD in this study. The need for prenatal screening for CAKUT and public education on the need to inculcate proper health seeking behaviors can therefore not be over-emphasized.

The high mortality and loss to follow-up asso­ciated with CKD predominantly resulted from sub-optimal care with infrequent dialysis ses­sions and inadequacy of other supportive treat­ments. Financial constraints on the parts of the parents or care-givers largely accounted for this. The cost of RRT is prohibitive globally, hence, comprehensive pediatric nephrology services may remain a mirage as long as care is patient- financed. Strengthening of health insurance schemes as well as advocacy for private sector support of health financing should therefore be pursued.

The previous report [11] from our center did not feature conditions like HIV-associated nephropathy and lupus nephritis, reflective of chan­ging disease epidemiology. Nationwide, nephrotic syndrome and acute glomerulonephritis [8],[9],[11],[12],[13] were the leading diagnoses, while inherited and genetic conditions like some tubulopathies, multicystic kidney disease, cystinosis, nephronopthisis and primary hyper-oxaluria were hardly reported. This may reflect under-diagnosis due to weak referral systems, non-recognition and a dearth of diagnostic facilities. It is however important to note that some of these conditions are associated with high rates of consanguinity [4] which is not not rampant in Nigeria.

Our study was limited by its retrospective design as some children may have been in­advertently excluded from the register. In addi­tion, emergency room records were excluded as they were largely incomplete. The prevalence reported in this study may therefore be an under-estimation. In view of this, a pros­pective study is currently under-way at our center.

In conclusion, the contribution of pediatric renal disease to overall childhood morbidity and mortality in our environment is on the increase. This study brings to the fore-light some of the challenges of pediatric nephrology practice in a resource-constrained setting. Em­phasis should therefore be placed on preven­tive nephrology. Effective referral systems, training of pediatric nephrologists and im­proved health care financing are advocated.

 
   References Top

1.White A, Wong W, Sureshkumur P, Singh G. The burden of kidney disease in indigenous children of Australia and New Zealand, epide­miology, antecedent factors and progression to chronic kidney disease. J Paediatr Child Health 2009; 46:504-9.  Back to cited text no. 1
    
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24.Roth KS, Carter WH Jr, Chan JC. Obstructive uropathy in children: Long-term progression after relief of posterior urethral valves. Pediatrics 2001;107:1004-10.  Back to cited text no. 24
    

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Correspondence Address:
Taiwo A Ladapo
Department of Pediatrics, College of Medicine, University of Lagos and Lagos University Teaching Hospital, Idi-Araba, Lagos
Nigeria
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DOI: 10.4103/1319-2442.139976

PMID: 25193924

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