3.0 Results
The results of the search process are summarized in figure 1. Out of 84
papers selected, 44 duplicates were removed. 40 papers were screened and
25 remained in full text screening. Finally, 7 papers were included in
the review. Three of the seven papers were from the south
east8,12, 15 hospital based study8and community based studies12,15. Those who took part
in the hospital study were male and female patients aged≥ 18 years with
sample size 908 (593 males and 315 females). The total mean age was
42.55± 15.43 years. Male (43.66±15.38 years) and female (40.48±15.31
years) (P<0.001). 86.5% were less than 60 years of age (Table
3). The study recorded a prevalence of 12%. It was observed that the
population based study were adults aged 25-64 years12,
recorded overall age and sex prevalence of 11.4%. The sample size was
1941 respondents. The mean age of all respondents was 43.7±13.20 years.
Male (44.1± 14.1 years) and female (43.4±12.6 years). Semi urban
(41.9±12.8 years) and rural population (47.6±13.0 years). Another
population based study15 recorded age and sex
prevalence of 7.8%. The sample 328 respondents aged≥ 18 years. The
total mean age of 54.8± 12.8 years in semi-urban. The two population
studies12,15 used convenience sampling technique.
Univariate binary logistic analyses were used in the studies to
determine the relationship between CKD and various variables. This was
followed by multiple logistic regressions using the variables from
univariate binary logistic analysis that were significantly associated
with CKD in order to determine the risk factors of CKD. The observed
risk factors was old age 12,15obesity15, diabetes mellitus12,
hypertension12,15 history of renal
disease15, low income occupation12.
Use of traditional medication12,15haemoglobin12, central obesity12,15,
glomerularnephrities8, bleaching cream and soap
containing mercury12.
4.0 Discussion
This review indicates that Southeast Nigeria bear substantial risk
factors. Report identified age, hypertension, obesity, history of
diabetes mellitus, use of herbal medicines and prolonged use of
non-steroidal anti-inflammatory analgesics as risk factors for CKD in
Nigeria10. There are other emerging risk factors such
as use of bleaching cream and use of soaps containing mercury25 which were in significant proportions. This calls
for a tailored programme to reduce the impact of these risk factors on
patients’ quality of life. A report showed that risk factors
interventions (blood pressure control, glycenic control, education) may
lower the risk of developing CKD26. However,
strategies to improve the prevention and early detection of chronic
diseases like CKD in low and middle income countries like Nigeria are
not only hampered by economic considerations, but also limited data
emerging from these countries. These countries have experienced rapid
deterioration of their chronic disease risk and mortality
profiles27. Multivariate analysis revealed that CKD
correlates with some risk factors such as hypertension, use of
nephrotoxins, low level of education and low income occupation among
others in these studied population. Age was significant in rural
communities while DM, reduce activity and low hemoglobin were associated
with CKD in semi-urban. The common risk factor (herbal remedies) is a
common feature of most studies in Nigeria9,12,15.
These could be explained by characteristics of Nigerian societies where
herbal medications were embedded in their custom. This is important
because, as most of these risk factors are modifiable, adequate blood
pressure control and improved education of these populations will help
reduce the prevalence of CKD.
Hypertension is the commonest cause of CKD especially in people of
African descent28. Initially only malignant
hypertension was identified as a significant cause of kidney damage,
however, more recently poor managed long term benign essential
hypertension has been established as a cause of
CKD/ESRD29. Naieker30 documented the
characteristics of African Patient with CKD and noted that CKD affect
mainly young adult aged 20 to 50 years and such patient present late
with hypertension. In Nigeria, hypertension ranges from 20 to over 40%
depending on the population studied31. It was observed
that in a market population and slum dwellers, the prevalence of
hypertension were about 40%32 and
53%33 respectively. A study recorded an overall age
and sex adjusted prevalence of 26.1%, (30.1% in semi urban and 18.9%
in rural)12 and noted that 48% were aware of their
disease and 89% of them were on treatment. The study documented that
awareness in hypertensive respondents was higher in women (51%) than
men (42%) and good control was achieved in only 36% of those on
medication12. These figures are high underlying the
risk of CKD if blood pressure is not controlled. A high prevalence of
hypertension had been consistently reported in various populations in
Nigeria34,35. Hypertension and cardiovascular diseases
are currently noted to disproportionately affect people in low and
middle income countries like Nigeria. About 17.5 million die each year
from cardiovascular disease globally, 75% of the death occur in low and
middle income countries like Nigeria36. The strong
association between hypertension and CKD highlight the central role of
endothelial dysfunction which is contributory to initiation and
progression of cardiovascular disease. This gives an idea of significant
risk to which many of our individual patients were subjected. Various
studies have documented low awareness in southeast
Nigeria33,35. It points to the important of early
diagnosis, screening and intervention against CKD and its complication.
However, this becomes alarming for settings were algorithms for early
screening and detection of disease risk factor are under assessed. It is
argued that the effect of blood pressure control can delay onset of
complication of CKD but this can achieved in a society with effective
health awareness and health seeking behaviour that may enhance the
opportunity for early detection and intervention.
DM is now the commonest cause of ESRD20 in North
America and Europe. It accounts for 54% of incident of cases as
documented in the USA renal data system37. The two
community studies documented that the age and sex adjusted prevalence of
DM were 5.9%12 and 7.9%15 These
references double that of 3.8% for Nigerian in the latest WHO
prevalence for African Countries which studied population of similar
age38. One of the studies reported that 75% were
aware of their disease, while 88% of those aware were on treatment and
72% of those on treatment were controlled12. Although
DM did not correlate with CKD in the latter studies, but this justifies
the screening exercise as identification and proper management of the
disease will assist in the reduction of the prevalence. This may be
because the prevalence of this population is still quiet low, hence its
impact on CKD as compared with hypertension is low.
The age and sex-adjusted prevalence of the metabolic syndrome in this
paper was 10.5%12. although, this is much lower than
in the developed world, where using the same National Cholesterol
Education program’s Adult Treatment Panel III (NCEP/ATP III) criteria,
the prevalence of metabolic syndrome in the United States was found to
be 34%39. It is a finding in our population that
needs further surveillance.
The prevalence of markers of CKD (proteinuria) in one community study
was 16.2% with the majority of them showing trace while 3.7% has
significant proteinuria. Prevalence of proteinuria (≥1+) increased from
3.3% in stage 1 to 100 percent in stage 5 CKD12. This
pattern is expected as higher prevalence of proteinuria is noted in
advanced CKD. The persistent significant proteinuria was
5.8%15 in another community study. It was observed
that Okafor et al 40 highlighting the enormity
of diabetic nephropathy in Enugu, documented that the prevalence of
albuminuria was 61.2%. This is alarming compared to 30% in United
Kingdom while Mexican American was 31%41. Moreover
studies conducted in Asian countries reported variability in the
prevalence of microalbuminuria ranging from 14.2% in Iran to 36.3% in
India42. The prevalence of microalbuminuria in
European countries was 26.9% in Hungary while microalbumuria was 16%
in Italy as well as Sweden, 9% in Germany43. There is
need for screening of microalbuminuria in diabetes. This may further
prevent renal damage by correcting factors such as hyperglycemia,
hyperlipidemia and hypertension.
The family history of kidney disease was reported as an independent risk
factor of CKD15. Among those with positive family
history of kidney disease, 38% were found to have CKD. This is higher
than 14.6% reported from China44 and 9.5% in KEAPS
study conducted in Yorkshine Northern England45. These
suggest that genetic factor may be contributing significantly in the
prevalence of CKD in the southeast. This is not surprising because Ulasi
et al46 had earlier reported that APOLI Genetic risk
variants are common in the Igbo population of south east Nigeria and
also highly associated with non-diabetic CKD in the area. These APOLI
risk variants have been shown to be strongly associated with increased
risk for non diabetics kidney disease among African
ancestry46
The toxicity of herbal medicine is related to the mixture of active
components, their interaction with drugs, contaminations and
adulterations. Some herbs that have aristolochic acid as a component
have been associated with nephropathy in a Chinese herbal
medicine47. In Nigeria, the use of nephrotoxins
contributes to about 38% of acute kidney injury9.
This is in agreement with the report documented in South African by
Seedat et al48 identifying herbal remedies and
infection as common medical cause of Acute Kidney Injury (AKI). AKI is
now an established cause of CKD49. In a study carried
out in Emene Southeast Nigeria, it was observed that 53.5% in rural
population used native medications while 36.5% in Semi urban admitted
to the use of such medications50. Because of the
kidney’s anatomic features and physiological functions as the primary
eliminator of exogenous drugs and toxins, the kidney is vulnerable to
various forms of injury51. Regular use of nephrotoxic
medication is an independent risk factor for CKD52.
Traditional remedies in Africa rarely have been analyzed and the active
nephrotoxic components have not been isolated nor characterized in most
cases. Many of the herbs are believe to be harmless and are commonly use
for self medication. Although regulation by The Food and Drug
Administration is part of the solution, increasing public awareness and
education are necessary to inform the public on the potential dangers of
using adulterated medicinal herbs.
The use of soaps containing mercury and bleaching creams is an emerging
risk factor which was considered to be rare among Nigerians but the
reverse is the case in present time. These agents have been long
established to be bad for the kidneys. Report documented that the use of
bleaching creams and soaps containing mercury was responsible for about
half of the cases of nephritic syndrome25. This fills
an important gap in the risk assessment of CKD as scanty population
level data exist, particularly among patients with co-morbidities
identified as vulnerable to CKD related complications. Other important
nephrotoxic agents rampant in our environment are petroleum and
petroleum products which are made up of hydrocarbons. Alasia et
al 53 showed in a study in Port Harcourt that
non-petroleum workers have high levels of hydrocarbon in their blood.
This is indeed alarming. The companies should clear the environment of
toxicants to safeguard the lives of rural dwellers.
The social economic factor across the study population show that
majority of people are more disadvantaged in terms of income earning.
The greater percentage of people is living in poverty. which the WHO
define in absolute term as low income <$2/day. The minimum
wage in Nigeria is N18,000/month which is approximately $108/ month and
categorized as low income54. This may be the reason
why the study population rely on alternative treatment such as spiritual
healing and traditional native healers which are affordable. The cost of
management of CKD in Nigeria is equal to $500 which is above the
minimum wage of a Nigerian worker. The study identifies disparity in the
accessibility of CKD risk screening awareness. This highlight the
consequences of health disparity where more affluent in society have
better access to health care. We noted that the respondents cite various
reasons for not seeking health check including cost which does affect
people’s habit where they do not seek health check when they are
apparently healthy therefore attitudinal changes which impact positively
on health outcome remains one of the public health messages that cannot
be avoided.