Prevalence of CKD-MBD in pre-dialysis patients using biochemical markers in Enugu, South-East Nigeria.

BACKGROUND: As kidney function declines, there is a progressive deterioration in mineral homeostasis with disruption of normal serum and tissue concentration of phosphorus and calcium, and changes in circulating levels of hormones-parathyroid hormone (PTH), calcitriol (1,25(OH)2 D), and Fibroblast growth factor-23 (FGF-23). OBJECTIVE: This study was aimed at determining the prevalence of markers of CKD-MBD in pre-dialysis patients. METHODS: We evaluated consecutively 168 subjects made up of 85 CKD patients and 83 healthy controls, who were attending the renal clinics and medical outpatient of University of Nigeria Teaching Hospital, Enugu. GFR was estimated and serum calcium, phosphorus, alkaline phosphatase, PTH, and 25(OH) D levels assayed. RESULTS: The prevalence of various mineral bone disease abnormalities were 70% hyper-phosphatemia, 85% hyper-parathyroidism, and 100% low levels of 25 (OH) D among the patients. Estimated GFR correlated negatively with both serum phosphorus, and PTH. Age of the patients ranged from18-76 years with a male to female ratio of 1.7:1. Chronic Glomerulonephritis (CGN), hypertension and diabetes mellitus caused CKD in 75% of the patients. There was no significant decrease in serum calcium levels of patients compared to controls. The patients did not have pathologically raised alkaline phosphatase, although their mean level was significantly higher than that of the control group. CONCLUSION: Low 25 (OH) D levels (insufficiency/deficiency), hyperparathyroidism, and hyper-phosphatemia were the obvious markers of CKD-MBD in our pre-dialysis patients. These should be evaluated at presentation in these patients.

High population frequencies of APOL1 risk variants are associated with increased prevalence of non-diabetic chronic kidney disease in the Igbo people from south-eastern Nigeria.

BACKGROUND: Continental Africa is facing an epidemic of chronic kidney disease (CKD). APOL1 risk variants have been shown to be strongly associated with an increased risk for non-diabetic kidney disease including HIV nephropathy, primary non-monogenic focal and segmental glomerulosclerosis, and hypertension-attributed nephropathy among African ancestry populations in the USA. The world's highest frequencies of APOL1 risk alleles have been reported in West African nations, overlapping regions with a high incidence of CKD and hypertension. One such region is south-eastern Nigeria, and therefore we sought to quantify the association of APOL1 risk alleles with CKD in this region. METHODS: APOL1 risk variants were genotyped in a case-control sample set consisting of non-diabetic, CKD patients (n = 44) and control individuals (n = 43) from Enugu and Abakaliki, Nigeria. RESULTS: We found a high frequency of two APOL1 risk alleles in the general population of Igbo people of south-eastern Nigeria (23.3%). The two APOL1 risk allele frequency in the CKD patient group was 66%. Logistic regression analysis under a recessive inheritance model showed a strong and significant association of APOL1 two-risk alleles with CKD, yielding an odds ratio of 6.4 (unadjusted p = 1.2E-4); following correction for age, gender, HIV and BMI, the odds ratio was 4.8 (adjusted p = 5.1E-03). CONCLUSION: APOL1 risk variants are common in the Igbo population of south-eastern Nigeria, and are also highly associated with non-diabetic CKD in this area. APOL1 may explain the increased prevalence of CKD in this region.

Left ventricular hypertrophy in African Black patients with chronic renal failure at first evaluation.

OBJECTIVE: Chronic kidney disease (CKD) is a major cause of cardiovascular morbidity and mortality all over the world. The combined effect of volume and pressure overload seen in patients with CKD is the primary cause of left ventricular hypertrophy (LVH). Though it accounts for a significant proportion of patients dying in hospitals in Nigeria, information on CKD in African Blacks is lacking. This study evaluates the prevalence of LVH and factors affecting it in pre-dialysis patients by using echocardiography. DESIGN, SETTING AND PATIENTS: One hundred consecutive patients with CKD who were attending the medical outpatient and renal clinics of University of Nigeria Teaching Hospital, Enugu, who satisfied the inclusion criteria were screened for the study. Eighty-eight patients completed the study. Forty-five age- and sex-matched subjects were selected as controls. Clinical and laboratory parameters and echocardiographic indices were measured. RESULTS: Left ventricular hypertrophy (LVH), defined in absolute terms as left ventricular mass index >134 g/m2 in men and >110 g/m2 in women was present in 95.5% of patients and 6.7% of controls. The most prevalent type of LVH was eccentric hypertrophy, which was found in 54.6%, while concentric was seen in 40.9%. Hypertension was present in 85.2% of the patients. The predominant causes of CKD were chronic glomerulonephritis (43.2%), hypertension (25%), and diabetes mellitus (14.8%). All the patients studied had advanced CKD, either stage 4 or 5 of the Kidney Disease Outcome Quality Initiative classification of CKD. Stepwise method of multiple linear regressions identified mean arterial pressure (32%), hemoglobin concentration (22%), male sex (17%), and creatinine clearance (24%) as predictors of LVH in CKD. CONCLUSION: This study showed a strong association between CKD and LVH in patients in developing countries at the time of first evaluation by a nephrologist. It demonstrated a high prevalence of LVH in patients at first evaluation. The patients were often anemic and had severe hypertension even at first presentation. Early detection and treatment of causes of CKD should be pursued aggressively at the primary prevention level, as has been advocated by the International Society of Nephrology to reduce the effects of CKD and its attendant complications in the society.