| dc.description.abstract | Background
Disorders of mineral metabolism, secondary hyperparathyroidism (SHPT),
hyperphosphatemia, hypercalcemia, and deficiencies of vitamin D are common
complications of chronic kidney disease (CKD). While their contributions to
the development of renal osteodystrophy are well known, recent evidence has
linked these factors to cardiovascular disease, including non-atherosclerotic
vascular calcification, excessive activation of the renin-angiotensin system,
hypertension, left ventricular hypertrophy, and death.
The obvious task ahead for health authorities in the developing world is to
identify patients at risk and evaluate for SHPT because early intervention may
slower arrest the progression of both bone and cardiovascular disease.
Objective of the study
To determine and describe the patterns, prevalence of hyperparathyroidism and
biochemical evidence of mineral bone disease in pre-dialysis patients with
chronic kidney disease at the Kenyatta National Hospital.
Methodology
A cross-sectional survey was carried out in 214 patients with chronic kidney
disease (CKD) consecutively recruited from the renal (nephrology) clinic, at the
Kenyatta National Hospital, over a period of 3 months. Patients with CKD had
their demographics, socio-economic and clinical history documented using an
administered-interviewer questionnaire. Patients had their glomerular filtration
rate (eGFR) estimated using Cockroft and Gault equation and staged as per the
kidney disease outcome quality initiative (KJDOQI) criteria. CKD patients in
stages 1 to 5, upon recruitment, had a study questionnaire administered to
determine the possible aetiology of kidney disease, presence or absence of
diabetesmellitus (DM), method of management of chronic kidney disease and
any clinical characteristics of bone disease. A structured physical examination
was then carried out.
Atenrollment 6ml of blood was drawn and the measurements of serum, blood
nitrogen urea, creatinine, albumin, calcium, potassium, phosphorus, alkaline
phosphatase, levels were determined using automated clinical chemistry
analyzer. Serum intact parathyroid hormone (iPTH) assays were performed
using electro-chemiluminescence Immunoassay (ECLIA) on the fully
automated immunoanalyzer Cobas Integra 400 Plus(Roche )Elecys.
Outcome Measures
Outcome measures were serum intact PTH levels, the KDOQI stages of CKD
andbiochemical features of bone turn-over.
Data management and Analysis.
All data was collected on a study proforma, and was entered into a computer
data base using Microsoft Access computer software and statistical analysis
was done using statistical package for social scientists (SPSS) version 15 after
cleaning and verification.
Values were expressed as means, medians and standard deviations (SD).
Point prevalence of hyperparathyroidism was determined as a percentage of the
number of patients with serum iPTH above the upper limit of normal, attending
the renal clinic in CKD stages 1 and 5, to the total study population.
Associations between the patients' socio-demographic data, presence of
Diabetes Mellitus(DM), stage of chronic kidney disease and serum iPTH level
were examined using chi-square test.
Differences in mean values in patients with or without DM were analyzed by
Student's t-test, if normally distributed, or Mann -Whitney U test for skewed
data, to determine statistical significance. Associations were considered
significant only when p value was equal or less than 0.05.
Analysed data was presented in the form of tables, pie-charts and graphs
Results
A total of 214 patients with chronic kidney disease, who were not yet on
dialysis, attending the renal clinic at the Kenyatta National Hospital over a
period of 3 months were studied.
The study population was categorized into 5 groups as per KlDOQI staging of
chronic kidney disease. CKD stage 1 had 7 participants, stages 2, 3,4 and 5 had
21, 70,42 and 74 participants respectively.
The mean eGFR was 3l.342 ±24.66 ml/min/l.73m2. This prevalence, of
hyperparathyroidism, was seen to increase as renal function, eGFR, declined.
The mean PTH level was 52.02 ±99.02 pgl ml. There was significantly more
low turn-over mineral bone disease observed in 78.4% (n= 109 out of 139)
compared to high turn-over mineral bone disease observed in only
2l.6%(n=30 out of 139) patients. Women were observed to have higher iPTH
levels and more high turn-over bone disease was observed.
This study, did not observe a significant correlation between the presence of,
diabetes mellitus, frequency of complaints of bone pain, or muscle weakness
with hyperparathyroidism.
There was a significant positive association between phosphorus and higher
levelsof serum iPTH but no significant association was found between calcium
andalkaline phosphotase.
Conclusion
This study demonstrated that hyperparathyroidism develops and progressively
worsens as glomerular function declines.
However, the overall prevalence of hyperparathyroidism in CKD patients
attending renal clinic at the Kenyatta National hospital was observed to be
lower than it is worldwide.
This study showed a trend towards more women registering higher iPTH levels
than the males. Biochemical high turn-over mineral bone disease was observed
more in women, with CKD, than the men.
In comparison to statistics from western countries, there seems to be more
biochemical low turn-over mineral bone disease in our patients as opposed to
more high turn-over mineral bone disease in the western populations. | en_US |
