**4.2 Osteitis fibrosa is the commonest type of rod**

Osteitis Fibrosa is a form of high turnover bone disease as a result of hyperparathyroidism. PTH assay was not done because of lack of facility in our center. However serum alkaline phosphatase was used as a surrogate. 78% of the CRF patients had raised levels of total serum alkaline phosphatase which correlate well with PTH levels and histological features of secondary hyperparathyroidism. This is in agreement with the work done by Duursma et al, (1975); Ritz et al (1974) and Hruska et al (1978). 66% of patients had Osteitis Fibrosa on histology. This finding agrees with the work of Jarava et al (1996) who found bone histological evidence of Osteitis Fibrosa cystica in 17 (85%) out of 20 haemodialysis patients in England. Our findings also agrees with that of shin et al (1999) who found Osteitis Fibrosa as the commonest type of ROD in predialysis patients in Canada (44%). This finding contradicts that if Coen et al (1996) who found mixed type ROD as the commonest type in predialysis CRF patient in England.

#### **4.3 There is correlation between histological evidence of rod and serum alkaline phoshatase**

In this study, it was found that 90% of patient had histological evidence of ROD on postmortem bone biopsy. This agrees with the finding Sanchez (2001), who found that 90% of patients with ESRD on maintenance dialysis have abnormal bone histology. Majority of patients are either predialysis or those who were not dialyzing adequately. It is known that once a patient start on maintenance, the prevalence of ROD increases. One of the contributing factors being aluminum deposition (from dialysate fluid), it means that the prevalence may even be higher if our patients are dialyzed adequately. In our study we found that all the patients that had histological evidence of ROD had elevated serum alkaline phosphatase levels. This finding may possibly be pointing to the fact that serum alkaline phosphatase can be used as a surrogate of parathyroid hormone as a predictor of ROD in our patients. This agrees with the finding of Urena et al, (1991) that in the absence of liver disease, serum alkaline phosphatase can be used to predict the presence of ROD. The finding is also in agreement with that of Duursma et al and Ritz et al who found that plasma alkaline phosphatase levels correlates with histological features of secondary hyperparathyroidism (HPTH).

#### **4.4 The yield of rod using radiological examination is low in our chronic renal failure patients**

In our study, we found only 2% of ROD using radiological examination. This agrees with Odenigbo (2003) who found 3.35% of ROD in Enugu using radiological examination. In this study, radiological evidence of ROD was not found in all 9(100%) patients who had histological evidence of ROD on postmortem bone biopsy. This agrees with the finding of

The Prevalence of Renal Osteodystrophy in

**4.9 Conclusion and recommendations** 

**4.9.1 Conclusion** 

**4.9.2 Recommendations** 

It is hereby recommended that:

renal failure patients.

**4.9.3 Limitation of the study** 

of Canadian patient, not necessarily due osteodystrophy.

Chronic Renal Failure Patients in Urban Niger Delta of Nigeria 69

Osteoarthritis (Odenigbo 2003). This study also agrees with the work of Harowin et al (1987) who found a high incidence of joint symptoms and radiological abnormalities in his group

In the study the mean serum calcium of CRF subject was 5.83± 2.1mg/dl. 37(71%) of CRF subjects had hypocalcaemia (<8.5mg/dl). This finding agrees with that of Slatoposky et al (1986). Calcium supplementation is a known modality for the treatment of hypocalcaemia. The mean serum phosphate of CRF patients in this was 6.1±2.0mg/dl. 41 (79%) had hyperphosphataemia (>4.5mg/dl). This agrees with finding of Slotoposky et al (1986) who demonstrated hyperphosphataemia even in moderate CRF. Dietary phosphate restriction

The findings of this study suggest that ROD which is a complication of chronic renal failure does exist in our environment. The study has also shown that Osteitis Fibrosa is the commonest type of ROD, and that ROD may be commoner in males. The study showed that in majority of patients with ESRD there is biochemical evidence. This finding may possibly be pointing to the fact that clinical features are a poor guide to the presence of ROD. Before now, it was thought that ROD hardly existed in our chronic renal failure patients, because they did not live long enough to manifest it. Though the findings of this study they agree with that, going by the low incidence of ROD using clinical symptoms and radiological methods, it is possible that in the nearest future, ROD may become more prevalent in on society. This is because there is now an increase in the availability of dialysis in many centers across the Nation, with possibility that many CRF patients may live long enough to develop ROD. The findings of this study suggest that serum alkaline phosphatase assay, a surrogate of parathyroid hormone, may be a good guide to the presence of ROD in our CRF

1. In all chronic renal failure patients, ROD should be anticipated. Serum calcium,

2. Dietary restrictions of phosphate should be enforced in our chronic renal failure patient

3. Calcium supplementation should be routinely part of the management of our chronic

4. Control of hyperparathyroidism in our chronic renal failure patient will be an integral

This study was faced with some limitations. It was not possible to carry out bone biopsies for live patients because of lack of consent from the patients. However, postmortem bone

**4.8 Hypocalcaemia and hyperphosphataemia is prevalent in our crf patients** 

and phosphate binding are effective methods of control of hyperphosphataemia.

patients. Majority of patients had hypocalcaemia and hyperphosphataemia.

phosphate, alkaline phosphatase should be done routinely.

as well as the use of phosphate binders,

part of management of CRF patients.

Hodsons et al, (1981) that there is a disparity between the radiological and histological evidence of ROD. In a study in Germany, Hodsons et al found only 7(41%) patients with radiological evidence of ROD out of 17 with histological evidence of ROD. Micheal et al (1998) found radiological features of ROD in 35% of CRF patients in ESRD.

There are some reasons for the low prevalence of ROD using x-rays. Firstly, the conventional techniques for x-ray contribute. Meama et al (1972) noted the phalanges to be normal in 67% if uremic patients using conventional techniques for X-ray films, and only 8% showed subperiosteal erosion. With the introduction of better films and the use of magnification techniques, only 26% appeared normal while 29% for exhibited subperiosteal erosion. There is no facility for magnification technique in the center where the study was done. Secondly, it has been reported that more than 50% of bone can be lost without any evidence in a radiograph, because only the cortical bone is clearly noted, and an important loss of cancellous bone should occur before radiological feature of ROD can be appreciated (Poznanki, 1993). Perhaps the fact that CRF patients in our environment have infrequent haemodialysis and do not live long enough for these changes to be detected on x-ray studies may be contributory to the low yield of ROD using radiological examination.

#### **4.5 Radiological and biochemical evidence of rod is more prevalent in esrd patients**

In our study, the only patient who had radiological evidence of ROD had a creatinine clearance of 6mls/min. 90% of the CRF patients had creatinine clearance <15mls/min (ESRD). The entire patients who had creatinine clearance <15mls/min had elevated serum alkaline phosphatase levels. Theses finding agree with the findings of Coen et al (1996) that adynamic bone disease is commoner n early stages of renal failure, while Osteomalacia and Osteitis Fibrosa cystica tend to occur as resistance to PTH develops, a situation which occurs in ESRD.

#### **4.6 ROD may be more prevalent in males**

In this study, the one patient who had radiological evidence of ROD was a male. Also, of the 9 patients that had histological evidence of ROD, 6(66%) were males, while 3(34%) were females, with a male- female ratio of 2:1, this finding is in contrast to the finding of Odenigbo et al (2003) in a study carried out at Enugu where ROD was found to be more prevalent in females. The finding also contradicts that of Couttenye et al (1997) who showed that women seem to develop hyperparathyroidism whereas men seems to more frequently develop aplastic bone disease. The reason why men in this study showed evidence of ROD more than women may be due to the fact that there were more men in this study, particularly in the group of 10 patients that had postmortem biopsy. However, the number of patients studied was small for a general statement to be made on gender difference.

#### **4.7 There is no correlation between symptoms of rod and biochemical or radiological evidence**

In the study, 7 (14%) of the CRF subjects had symptoms suggestive of ROD. Of these, 5(71%) had bone pain while 2 (29%) had radiological evidence of ROD ('Rugger Jersey" spine), while 3 (80%) had radiological features of osteoarthritis. This agrees with the finding of Odenigbo, who reported that out of the 11 patients who had bone pain, none had radiological evidence of ROD, but all patients who had radiological evidence of Osteoarthritis (Odenigbo 2003). This study also agrees with the work of Harowin et al (1987) who found a high incidence of joint symptoms and radiological abnormalities in his group of Canadian patient, not necessarily due osteodystrophy.
