**1. Introduction**

46 Chronic Kidney Disease

Vliegenthart R, Oudkerk M et al. (2002). Coronary calcification detected by electron-beam

Calcification Study. Eur Heart J.; 23(20): 1596-1603.

computed tomography and myocardial infarction. The Rotterdam Coronary

Chronic renal failure (CRF) is defined as a progressive and persistent deterioration in renal function with serum creatinine consistently greater than 175µmol (Adelakun and Akinsola, 1988). It occurs as the termination of many chronic renal diseases, and is an important cause of morbidity and mortality in Africa (Kadiri, 2001). End stage renal failure may be defined as creatinine clearance of less than 10mls/minute or sustained plasma creatinine concentration above 500pmol/l (Ojogwu, 2001).

In United Kingdom the prevalence of chronic renal failure is approximately 600 individuals per million population per year (0.06%). The incidence of end-stage renal failure is of the order of 200 per million population per year (0.02%) (Baker, 1999).

In Nigeria, although accurate figures are not available, the size of the problem has been estimated using hospital admission records (Kadiri, 2001). Hospital admission rates of CRF in South West Nigeria were reported as between 6.7%-8% (Akinsola et al, 1989; Kadiri and Arije, 1999). However, much earlier reports by Adetuyibi *et al* showed that CRF accounted for 11.4% of deaths on the medical wards of a major teaching hospital in the region (Adetuyibi et al, 1976).

Chronic glomerulonephritis and hypertension account for majority of CRF cases in Nigeria, with diabetes mellitus, obstructive uropathy and autosomal dominant polycystic kidney disease accounting for smaller proportions (Akinsola et al, 1989). Chronic interstitial nephritis is thought not to be a common cause of CRF in Nigeria and other parts of Africa (Gold et al 1990, Ojogwu 1990, Mate-Kole et al 1990). Once established, chronic renal impairment tends to progress inexorably to end-stage renal failure, but the rate of progression depends on the underlying aetiology: for example chronic glomerulonephritis leads to a more rapid deterioration compared with chronic tubulointerstitial nephropathies (Baker, 1999). Chronic renal failure is associated with widespread complications, and renal osteodystrophy (ROD) is one of such complications (Hartmut and Marie-Claude 1990). ROD develops in the early stages of loss of the excretory functions of the kidney, and can begin many years before its symptoms and radiological changes appear in adults (Hartmut and

The Prevalence of Renal Osteodystrophy in

University of Benin Teaching Hospital (UBTH).

3. Patients aged between 18years and 65years.

2. Those who have had or are on vitamin D therapy

Fisher's formula for determining sample size was used. This is:

4. Those who indulge in excessive alcohol intake

Oyo States.

**2.3 Subjects** 

**2.2 Type of study** 

**2.4 Inclusion criteria** 

Committee of the UBTH.

**2.5 Exclusion criteria** 

Exclusion from the study included: 1. Patients aged below 18years

3. Those with chronic liver disease

7. Patient with metastatic bone disease.

5. Post menopausal women. 6. Bed ridden patients.

**2.6 Sample size** 

q= 1-P

n= 86.7=87

was used.

n= number of sample size

p= prevalence of the problem =0.06%

z= 95% confidence interval =1.96 d= level of precision =0.05

diameter.

Chronic Renal Failure Patients in Urban Niger Delta of Nigeria 49

patients come from Edo State (where the hospital is situated), Delta, Anambra, Ondo, and

The study group was made up of consecutive chronic renal failure patients attending the

1. Ultrasonographic findings of bilaterally shrunken kidneys of less than 9cm bipolar

The subjects were recruited after obtaining informed consent from them (and /or relations when necessary). Also ethical approval was sought and obtained from the Ethical

> Z2Pq <sup>N</sup> d2

However since this was a pilot study, sample size of approximately 50% of above (that is 50)

The study was prospective, descriptive, Clinico-pathological and hospital based.

2. Persistently elevated serum creatinine concentration above 175 µmol/l.

Marie-Claude 1990). Symptoms of ROD are seen only in about 10% of pre-dialysis patients, but when they have been on dialysis for several years, 90% of them will have symptoms (Sanchez 2001). When glomerular filtration rate (GFR) falls to 50% of normal, more than 50% of patients exhibit abnormal bone histology. As much as 90% of patients with end-stage renal failure on maintenance haemodialysis have abnormal bone history.

The bone disorders associated with chronic renal failure are; Osteitis Fibrosa cystica due to secondary hyperparathyroidism, osteomalacia, osteoporosis. Adynamic osteopathy, skeletal microglobulin amyloid deposit, aluminum related low turnover bone disease and mixed forms of ROD. Osteitis Fibrosa is the commonest form of ROD (Hartmut and Marie-Claude 1990). All these increase the morbidity and mortality in patients with CRF. The prevalence of the different types of ROD may vary depending on aluminum exposure, treatment with Vitamin D metabolites, dietary intake, and whether or not is undergoing dialysis (Hartmut and Marie-Claude 1990).

The diagnosis of ROD can either be by invasive or non invasive methods. The invasive methods include: bone biopsy after double tetracycline labeling, scintigraphical scan studies, computed tomography and bone densitometry (Sanchez 2001). A definitive diagnosis of ROD can only be made with bone biopsy. The non invasive methods employ the use of serum markers of bone metabolism, including bone-specific alkaline phosphatase (bap), pre collagen type 1 carboxy1- terminal extension peptide (PICP), osteocalcin, pyridinoline (PYD), tartrate resistance acid phospatase (TRAPE) and intact parathyroid hormone (IPTH), and skeletal x-ray (Sanchez 2001). Indeed, detection of biochemical makers such as serum bap can predict the presence of ROD. Serum bap is a specific and sensitive marker that is used to evaluate the degree of bone remodeling in uraemic patients (Sanchez 2001, Urena et al, 1991). Also intact PTH and several relatively new bone markers such as PYD and PICP are of immense value in the non-invasive diagnosis of ROD. In patients that do not have liver disease, parathyroid hormone and alkaline phosphatase are less expensive and noninvasive alternatives for evaluation of ROD (Urena et al, 1991). These biochemical markers have the added advantage of allowing for repeated measurements, and therefore make possible the study of short term changes in bone turn over and the effect of treatment (Coen et al 1998). They may be used to predict the risk of fracture (independently of bone loss), Rate of bone loss and also the response to therapy (Coen et al 1998).

In developing countries like Nigeria, these non-invasive and relatively less expensive methods for evaluating bone changes in CRF patients will be a very useful alternative to the invasive and relatively more expensive method used in developed counties.

Because of paucity of data, the prevalence of ROD in Nigeria is not known, however the prevalence of ROD in University of Nigeria Teaching Hospital Enugu using skeletal x-ray was reported to be 3.35% (Odenigbo, 2003). With the increase in the number of patients with CRF requiring or undergoing dialysis across Nigeria, it has becomes necessary to study the extent of ROD in CRF patient with or without dialysis.
