Mineral and bone disease in black african hemodialysis patients: a report from senegal

Prevalence and pattern of chronic kidney disease-mineral bone disorders among hemodialysis patients in kano, northwest nigeria

Introduction:

Mineral and bone disorders (MBD) are among the important complications of chronic kidney disease (CKD) including end-stage renal disease. In addition to the higher rate of all-cause and cardiovascular-related mortality, MBD is also a cause of significant morbidity in CKD patients.

Materials and Methods:

This is a cross-sectional study of all consenting patients on hemodialysis at Aminu Kano Teaching Hospital, between December 2011 and June 2012. With the aid of an interviewer-administered questionnaire, the demographic profile and clinical features of the patients were obtained. After a general physical examination, blood sample was taken for the determination of calcium, phosphate, intact parathyroid hormone, 25 hydroxy (25[OH]) Vitamin D₃, packed cell volume, serum creatinine, and potassium.

Results:

Forty-eight patients on maintenance hemodialysis were recruited for the study, 39 (81.3%) were male and 9 (18.8%) were female. The age range was 40–59 years, with a mean of 45.96 ± 13.7 years. Chronic glomerulonephritis was the predominant cause of CKD (25%). Hyperphosphatemia was noted in 19 (39.5%) of the patients, whereas 22 (46%) had hypocalcemia. In 26 (54.1%) of the patients, the calcium-phosphate product was >4.55 mmol²/L². We found that 58% of the patients had CKD-MBD, of which 15 (31%) had secondary hyperparathyroidism, whereas 13 (27%) had features suggestive of adynamic bone disease. None of the patient had normal serum 25(OH) Vitamin D₃ (mean: 43.79 ± 21 ng/ml).

Conclusion:

CKD-MBD is common among patients on hemodialysis in our center. Screening for CKD-MBD and appropriate use of phosphate binder and Vitamin D when indicated are highly recommended.

Vitamin D, bone alkaline phosphatase and parathyroid hormone in healthy subjects and haemodialysed patients from West Africa: impact of reference ranges and parathyroid hormone generation assays on the KDIGO guidelines

BACKGROUND

The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines recommend targets based on multiples of the upper limit of normal (ULN) of parathyroid hormone (PTH) concentration. However, the ULN has not always been correctly established by manufacturers. While it is known that the ULN is supposed to be higher in African Americans than in Caucasians, it is largely unknown in Africans.

METHODS

We established the ULN of PTH concentration in a population of 240 healthy Ivorians using second- and third-generation PTH assays before and after supplementation with 100 000 IU of cholecalferol. We measured the levels of PTH, bone alkaline phosphatase, 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D in 100 haemodialysed Ivorian patients.

RESULTS

The prevalence of vitamin D deficiency in Ivory Coast is low. The ULN obtained using the third-generation PTH assay was similar to that obtained in Caucasians but was higher when PTH was measured using the second-generation PTH assay. According to the KDIGO guidelines, ∼20% of the haemodialysed patients were below twice the ULN and 30% were above nine times the ULN. Approximately 25% of the patients were even >12 times the ULN. We observed a discrepancy in the results between the two PTH assays (14%) that was relatively more important than what we observed from previous studies in Caucasians using the same strategy.

CONCLUSIONS

We found a low prevalence of vitamin D deficiency in a tropical country like Ivory Coast. We also established the PTH reference range, which could prove useful for the follow-up of haemodialysed patients, particularly for the large number of patients suffering from secondary hyperparathyroidism who are at high risk of adverse bone events.

Secondary hyperparathyroidism among Nigerians with chronic kidney disease

BACKROUND

Secondary hyperparathyroidism (SHPT) is a manifestation of chronic kidney disease mineral bone disorder (CKD-MBD). SHPT is common in patients with chronic kidney disease (CKD) and is associated with significant morbidity and mortality.

METHODS

A cross- sectional descriptive study involving 230 patients with CKD.

RESULTS

The mean age of the study population was 44.17±15.24 years. The median intact parathyroid hormone and alkaline phosphatase levels were 96pg/ml (range 4-953pg/ml) and 88 iu/l (range 10-800 iu/l) respectively. The mean (with standard deviation) calcium, serum phosphate, calcium phosphate product and haemoglobin levels were 2.22±0.29mmol/l, 1.8±0.62mmol/l, 3.94±1.42mmol2/l2 and 9.90±1.87g/dl respectively. Majority of patients had advanced CKD with 70.3% of patients in stage G5. The prevalence rates of SHPT, hypocalcaemia, hyperphosphataemia, elevated alkaline phosphatase and elevated calcium phosphate product were 55.2%, 34.8%, 66.1%, 42.2% and 25.2% respectively.Univariate analysis revealed that SHPT was associated with hypocalcaemia, hyperphosphataemia, elevated alkaline phosphatase, proteinuria, anaemia, hypertension, left ventricular hypertrophy and stage of kidney disease; being worse with advancing kidney disease. Independently associated with SHPT were hypocalcaemia (OR=4.84), hyperphosphataemia (OR=3.06), and elevated alkaline phosphatase (OR=2.04).

CONCLUSION

The prevalence of SHPT in CKD is high, occurs early and is independently associated with hypocalcaemia, hyperphosphataemia and elevated alkaline phosphatase. The prevalence of SHPT also increases with worsening renal function.

Biochemical markers of mineral bone disorder in South African patients on maintenance haemodialysis

BACKGROUND AND OBJECTIVE

Despite the high mortality and morbidity associated with abnormalities in mineral and bone metabolism in haemodialysis patients, there is limited data on the pattern of mineral bone disorder in African CKD population. Therefore, the purpose of this study was to describe the pattern of mineral bone disease by evaluating biochemical parameters in patients on maintenance haemodialysis (MHD).

METHODS

We evaluated the serum/plasma intact parathyroid hormone (iPTH), corrected calcium, phosphate, total alkaline phosphatase (TALP) and 25 -OH vitamin D levels of two hundred and seven patients undergoing MHD at two dialysis centers in Johannesburg.

RESULTS

The MHD patients (133 men, 74 women) had a mean age of 54.5±15.6 years with a median dialysis vintage of 24 months (IQR, 12-48) and a mean kt/V of 1.45±0.28. The prevalence of hyperparathyroidism (iPTH >150 pg/ml), hyperphosphataemia, hypocalcaemia and 25-OH vitamin D deficiency (<30 ng/ml) was 73.4%, 57.0%, 20.3% and 80.7 % respectively. The combination of markers of bone turnover (iPTH >150pg/ml and TALP> 112 U/L) suggestive of high turnover bone disease, was present in 47.3 % of the study population. In multiple-logistic regression analysis, the odds ratio for developing hyperparathyroidism with hypocalcaemia and hyperphosphataemia were 5.32 (95% CI 1.10 - 25.9, P = 0.03) and 3.06(95 % CI 1.15 - 8.10, P=0.02) respectively. Ninety eight (47.3%) of the MHD patients had iPTH within the recommended kidney disease improving global outcome (KDIGO) guidelines.

CONCLUSION

Secondary hyperparathyroidism and 25-OH vitamin D deficiency were common in our haemodialysis patients. Hypocalcaemia and hyperphosphataemia were strong predictors for developing secondary hyperparathyroidism.