INTRODUCTION

The burden of renal disease worldwide appears to be on the increase. It is estimated that kidney disease affects over 8-10% of the general population worldwide, amounting to over 800 million people 1,2.

 

	Corresponding Author: Dr. Ojeh-Oziegbe Odigie E O University of Benin/ University of Benin Teaching Hospital, Benin City. Email: osezuwaonose@yahoo.com

 

 

 

 

 

 

The situation is particularly of concern especially in Sub-Saharan Africa. In the 2016 review of the Global Burden of Kidney Disease, the database showed an 87% rise of CKD and a doubling of CKD deaths between 2000 and 2016 3. This is because there is a significant shortage of public health services especially relating to renal case. The issue of renal replacement therapy, especially in established chronic kidney disease (CKD) is a major issue as renal replacement therapy (RRT) with hemodialysis, peritoneal dialysis and kidney transplant is largely unavailable, and where available, involves a high financial burden to the patients and their relations. This is especially important in Nigeria where the burden of renal replacement therapies fall on the patient and their relations. 4,5

In Nigeria, hemodialysis is the main method of treatment for those with End Stage Kidney Disease (ESKD). The hemodialysis centers are mainly located in the urban areas of the country. In addition to this, dialysis costs are expensive and largely out of reach to those needing dialytic therapy. Transplant centers are just a few and the cost of transplant extremely prohibitive. 5,6,7,8,9

Apart from dialytic therapy, CKD patients present with a lot of issues. They have anemia and heart disease, as well as hypertension. The treatment of anemia is also expensive. Kidney disease has been found to be associated with hypertension, diabetes, older age, black race, infection mediated glomerulonephritis and a host of other unidentified etiology.

CKD incidence and prevalence is on the rise. Death from CKD rose by 32.1% from 2015-2016. It is one of the leading causes of mortality and shown a progressive increase in the number of associated deaths in the last 2 decades.

It also represents an exceptionally large economic burden in low income countries, more so as they are the least equipped to deal with its consequences. In resource poor countries like Nigeria, preventive strategies would be a lot more effective.

It is therefore important that kidney disease is identified early and that preventive strategies to avoid and mitigate the course of kidney disease to be implemented as early as possible.

 The need for early detection and therefore early intervention cannot be overemphasized. Early detection in our environment has generally included urinalysis to check for proteinuria, electrolytes and urea, and creatinine.10

The ability to do basic urea and electrolytes and urinalysis are tools that are readily available, but the observation has been that such tools are rarely used by the generality of populace on their own.

They benefit from these when mass screenings are done. These are regularly not done and when done, are usually as a result of programs like World Kidney Day screening, and the cost of tests are usually borne by the Nephrologists, the nurses and a few pharmaceutical companies involved out of their pocket expenditure.

The value of screening for kidney diseases leading to early detection is an important phenomenon in developed countries. In Nigeria, it is virtually not done as a government outreach towards detection of kidney diseases but sporadically by well-meaning health professionals and they also have to bear the cost.

Treatment of kidney disorders when detected at an early stage is feasible, acceptable, cost effective and generally affordable. Treatment of kidney disease in Nigeria at an advanced stage, when they usually present on the other hand is in many cases not feasible as there are few renal replacement centers and Nephrologists sometimes not acceptable to some groups who do not accept blood transfusion as a mode of anemia management, not cost effective and most importantly, not affordable to the majority of Nigerians as there is no government sponsored or subsidized renal replacement program. 11,12

Therefore, the mainstay of renal care in Nigeria is for now resting on the base of early detection of kidney disease and also involves screening for kidney disease itself and also for the risk factors of chronic kidney disease such as hypertension and diabetes.

Screening for kidney disease has been done in various communities in Nigeria and has shown a variety of prevalence, all significant, in different communities in Nigeria.

Most of these screenings have mainly been done using urinalysis to detect proteinuria.

Other screenings have used urinalysis to try and detect microalbuminia using micral test strips.

Few have used serum creatinine and calculated the estimated Glomerular Filtration Rate (eGFR). This has been found to detect a larger portion of renal disorders, especially in those with normal or borderline serum creatinine values, but the practice of using eGFR has not been used as a screening too in our environment.

Detecting those cases of occult kidney disease would enable us to be able to catch a larger number of kidney disease cases at a much earlier time thus enabling preventive measures to be taken on time to avoid overt kidney diseases.

The immediate way forward is early detection. This will allow for the detection of those with kidney failure and allow for management to slow down the progression of the kidney disease and prolong, for as much as possible, the development of End Stage Kidney Disease (ESKD). Achieving this means screening for kidney disease in various communities and different population groups.13

However, there is a downside of using eGFR and certain studies have observed that single eGFR can overestimate prevalence of CKD 14, while others agree on its effectiveness.15

This study was carried out as part of the World Kidney Day. The study was done in the Nigerian Institute For Oil-palm Research (NIFOR), in a rural population in South-South Nigeria.

 

Materials and Methods:

This study was cross sectional and carried out as a part of the World Kidney Day 2014. Data for the study were extracted from the WKD screening of workers from NIFOR with ethical clearance and permission granted by the management of the Nigerian Institute for Oil Palm Research, Benin City.  242 patients, all between the ages of 18-80, were evaluated. Pregnant women were not included in the sample selection. Blood pressure, random blood sugar, height, weight and sociodemographic data were obtained and/or measured. Blood samples were also taken for serum creatinine. As part of the screening for WKD rural screening, chronic kidney disease was defined as a serum >1.5 mg/dL.

Weight was measured in kilograms to the nearest kg, height was measured in centimeters to the nearest centimeter. These were used to calculate the Body Mass Index (BMI), given as weight (kg)/ height squared (m2).

BP was measured using mercury sphygmomanometers in the sitting position. The average of two BP measurements taken 5 min apart in the left arm was recorded for each participant. HTN was taken as the presence of systolic BP (SBP)≥140 mmHg and/or diastolic BP (DBP)≥90 mmHg. Systolic HTN was defined as SBP≥140 mmHg with a DBP< 90 mmHg, whereas diastolic HTN was defined as DBP≥90 mmHg with a SBP < 140 mmHg. Participants who admitted to being known hypertensives were considered to have good BP control using a cutoff BP value of <140/90 mmHg.
The prevalence of HTN in the study population was taken as the number of self-reported known hypertensives and persons found to have HTN during the study.

Waist–hip ratio (WHR) was determined using the waist circumference (measured at the midpoint between the lowest rib margin and the iliac crests) and the hip circumference (measured at the widest point around the buttocks). Abdominal obesity was taken as WHR > 0.85 for women and WHR > 0.9 for men.

RBS was done using glucose meters and strips (Accu-Chek, Roche diagnostics, Mannheim, Germany). Random blood sugar levels ≥200 mg/dl were considered high and abnormal.

Serum creatinine was determined using the modified Jaffe’s method. Serum creatinine of <1.4 mg/dL was considered normal. 138 participants with a normal serum creatinine of ≤1.4mg/dl were further evaluated using the 2009 CKD_EPI equation to calculate their eGFR. There were 138 participants with complete results.

Results are presented as follows.

Statistical Analysis:

Data obtained were analysed using IBM SPSS Ver. 21 and Microsoft Excel 2016. Quantitative data were presented as means + standard deviation, qualitative data are presented as frequencies and percentages.

 

Results:

Range of serum creatinine for the entire group was 0.2-1.4 mg/dl. Mean serum creatinine was 0.978 ±0.28 mg/dl. For males (N=62) serum creatinine mean was 1.065 ±0.251 mg/dl, and for females (N=76) it was 0.907±0.284 mg/dl. Mean eGFR across the group was 96.69±32.064 mls/min. For males (N=62) mean eGFR was 95.097±27.185 mls/min, and for females (N=76) it was 97.99±35.68 mls/min. For those with an eGFR <60mls/min (N=13), total mean was 56.723±3.67 mls/min, for males (N=2) it is 59.2±0.88mls/min, and for females(N=11) it is 56.27±3.83 mls/min.

Discussion:

The primary definition of chronic kidney disease was estimated Glomerular Filtration Rate (eGFR) less than 60 mls/min per 1.73 m2 Body Surface Area (BSA)16.

Serum creatinine only has been found to underestimate GFR, so using equations for calculating the eGFR has been used by researchers and clinicians.

This study showed a prevalence of 9.42% of the study population had an eGFR of <60 mls/min in this population that had a serum creatinine of ≤1.4mg/dl.

It is also important to know that the prevalence of serum creatinine of ≥1.5 mg/dl found in this group of participants were found to be 20.4%. 17

So it meant that a further 9.42% of the remaining participants adjudged to have a normal renal function had a GFR of less than 60 mls/min. This has been the finding in some other studies and the suggestion had been that prediction equations for GFR should be used more commonly to assess renal function as some individuals with impaired renal function could not be detected by using serum creatinine values alone. While this is in agreement with the Kidney Disease Outcome Quality Initiative (KDOQI) guidelines, some have argued that it is not cost effective. The downside of this argument is that once the serum creatinine is done and the sociodemographic data collected, it does not have additional costs to use a prediction equation to calculate the eGFR.

The added advantages of using eGFR as a tool for early detection of CKD is that it may be possible to detect the disease at an earlier stage and identify the risk factors in those subjects. When such risk factors, which commonly are hypertension and diabetes are known, it would be possible to intervene and mitigate such risk factors thereby possibly stopping the progression of kidney disease.

Even when such risk factors are unknown, as happens in a significant number of kidney disease patients. It would enable clinicians to follow up those at risk for progression of kidney disease and take appropriate action to significantly slow down disease progression.

Certain associations with having a low eGFR found here included abdominal obesity as over 80% of those with reduced eGFR despite having a normal serum creatinine had abdominal obesity. This, for example, is a situation that can be mitigated with lifestyle modification.

 

Conclusion

This study shows that there is a significant number of kidney disease cases (9.42%) who have an eGFR of ≤60mls/min despite having a normal creatinine level.

It encourages the use of prediction equations, in this case, the CKD_EPI equation to calculate the eGFR so as to identify cases of occult renal disease that cannot be detected by serum creatinine values alone.

For a country like Nigeria with an estimated population of 210 million people, 9.42% would mean a population prevalence of close to 20 million people who may have a normal kidney function by serum creatinine assessment alone.

This is a very large number and more studies would need to be done to ascertain the prevalence of occult kidney disease in the presence of a normal serum creatinine value.

 

References

1. Nugent RA, Fathima SF, Feigl AB, Chyung D. (2011). The burden of chronic kidney disease on developing nations: a 21st century challenge in global health. Nephron. Clinical practice, 118(3), c269–c277. https://doi.org/10.1159/000321382

2. Alebiosu CO, Ayodele OE. The global burden of chronic kidney disease and the way forward. Ethn Dis. 2005 Summer;15(3):418-23. PMID: 16108301.

3. Jha V, Modi GK. Getting to know the enemy better-the global burden of chronic kidney disease. Kidney Int. 2018 Sep;94(3):462-464. doi: 10.1016/j.kint.2018.05.009. Epub 2018 Aug 3. PMID: 30078513.

4. Ojeh-Oziegbe OE, Okaka E, Oviasu E. Cost Evaluation of Haemodialysis for End Stage Renal Disease Patients: Experience from Benin City, Nigeria. Annals of Biomedical Sciences 2013. Vol 12 No. 2 eISSN: 1596-6569. Retrieved from https://www.ajol.info/index.php/abs/article/view/93716

5. Ajayi S, Raji Y, Bello T, Jinadu L, Salako B. Unaffordability of Renal Replacement Therapy in Nigeria. Hong Kong Journal of Nephrology,2016, Vol. 18, pp 15-19. doi:https://doi.org/10.1016/j.hkjn.2015.11.002.

6. Dada SA, Ajite AB, Ibitoba FA, Thomas AA, Dada OE, et al. Challenges of haemodialysis: A single centre experience in South West Nigeria. J Clini Nephrol. 2019; 3: 055-060. DOI: 10.29328/journal.jcn.1001026

7. Okoye O, Mamven M. Global Dialysis Perspective: Nigeria. Kidney360. 2022 Jul 14;3(9):1607-1610. doi: 10.34067/KID.0002312022. PMID: 36245658; PMCID: PMC9528372.

8. Bamgboye EL. Hemodialysis: Management Problems in Developing Countries, with Nigeria as a surrogate. Kidney Int Suppl. 2003 Feb;(83):S93-5. doi: 10.1046/j.1523-1755.63.s83.19.x. PMID: 12864883.

9. Ekrikpo UE, Udo AI, Ikpeme EE, Effa EE. Haemodialysis in an emerging centre in a developing country: a two year review and predictors of mortality. BMC Nephrol 12, 50 (2011). https://doi.org/10.1186/1471-2369-12-50

10. Bosan IB. Recommendations for early diagnosis of chronic kidney disease. Ann Afr Med. 2007 Sep;6(3):130-6. doi: 10.4103/1596-3519.55719. PMID: 18240503.

11. Dobber , R. (2021, March 11). Early detection of chronic kidney disease can save lives and cut costs. Retrieved from World Economic Forum: https://www.weforum.org/agenda/2021/03/early-detection-chronic-kidney-disease-save-lives-cut-costs/

12. Tonelli M, Dickinson JA. Early Detection of CKD: Implications for Low-Income, Middle-Income, and High-Income Countries. J Am Soc Nephrol. 2020 Sep;31(9):1931-1940. doi: 10.1681/ASN.2020030277. Epub 2020 Aug 24. PMID: 32839279; PMCID: PMC7461685.

13. Centers for Disease Control and Prevention. Chronic Kidney Disease Initiative. Testing and Treatment: Find it Early, Treat it Early.2001.  Retrieved From: https://www.cdc.gov/kidneydisease/publications-resources/annual-report/ckd-testing-treatment.html#print

14. Bottomley MJ, Kalachik A, Mevada C, Brook MO, James T, Harden PN. Single estimated glomerular filtration rate and albuminuria measurement substantially overestimates prevalence of chronic kidney disease. Nephron Clin Pract. 2011;117(4):c348-52. doi: 10.1159/000321515. Epub 2010 Oct 15. PMID: 20948233.

15. Gambaro G, Bonfante L, Abaterusso C, Gemelli A, Ferraro PM, Marchesini S, De Conti G, D'Angelo A, Lupo A. High chronic nephropathy detection yield in CKD subjects identified by the combination of

 

Table 1: Mean Parameters of Study Participants

Variables (N = 138)	Mean	S.D.
Age (years), of which	46.22	± 14.852
Weight (kg)	65.196	± 13.317
SBP (mmHg)	129.09	± 19.807
DBP (mmHg)	79.16	± 12.222
Serum Creatinine (mg/dL)	0.978	± 0.28
eGFR	96.69	± 32.064
RBS	122.57	± 56.669
Waist/Hip Ratio	0.911	± 0.073
BMI	24.77	± 4.648

 

 

 

 

 

 

 

 

 

 

Table 2: Comparison of Mean parameters of participants according to gender

Variable	Sex of Patient	N	Mean	Standard Dev.
Age (years)	Male	62	52.29	± 15.135
	Female	76	41.28	± 12.703
Systolic BP 1 (mmHg)	Male	62	133.02	± 19.264
	Female	76	125.95	± 19.798
Diastolic BP 2(mmHg)	Male	62	80.89	± 11.453
	Female	76	77.78	± 12.711
Serum Creatinine (mg/dl)	Male	62	1.065	± 0.251
	Female	76	0.907	± 0.284
BMI	Male	62	23.007	± 3.102
	Female	76	26.22	± 5.197
Weight (kg)	Male	62	64.246	± 11.948
	Female	76	65.98	± 14.382
Waist to Hip Ratio	Male	62	0.9311	± 0.073
	Female	76	0.895	± 0.07
RBS	Male	62	137.9	± 70.81
	Female	76	110.67	± 39.136
eGFR	Male	62	95.097	± 27.185
	Female	76	97.994	± 35.68

 

 

Table 3:  Further Information on Study Participants (Total N = 138)

	N	(%) of Total N
Males	62	44.93%
Females	76	55.07%
Haematuria	6	4.35%
Proteinuria	7	5.07%
Hypertension	35	25.36%
DM	7	5.07%
eGFR<60	13	9.42%
Abdominal Obesity (WHR)	101	73.19%
Males	42	30.43%
Females	59	42.75%
Obesity  (BMI)	20	14.49%
Males	2	1.45%
Females	18	13.04%

 

Fig 1: Participants based on eGFR.

 

 

Figure 2: Means comparisons of Blood Pressure between Males and Females

 

Figure 3: Comparison of eGFR values in patients with Normal Serum Creatinine