**2.7 Study design**

The eventual 52 subjects who satisfied the inclusion criteria were required to complete a researcher administered questionnaire which includes age, sex, occupation, dietary habits, clinical symptoms of ROD, frequency and regularity of dialysis. Physical examination was performed by the investigator.

Ten milliters (10ml) of venous blood was drawn from the remaining 60 patients from a suitable vein with loose fitting tourniquet. The blood sample was used to assay for serum alkaline phosphatase levels, bone specific alkaline phosphatase levels, serum albumin levels, calcium and phosphate levels.

Osteocalcin, hydroxyproline, parathyroid hormone and calcitriol assays were not carried out because of lack of necessary facilities. However, a surrogate for parathyroid hormone was taken as total serum alkaline phosphatase.

Glomerular filtration rate was determined by 24hour urinary creatinine clearance. Also 24hour urine calcium was determined from the 24 hr urine. Plain x-rays of the wrist/ phalanges of both hands and / or lumbo-sacral spine to include the pelvis was carried out looking out for features of osteodystrophy. Bone histology, though more sensitive in the diagnosis of ROD than radiographic evidence could not be done in live subjects because consent for the procedure was refused. 20 of the CRF patients died during the study. However, out of these, only 14 died in the hospital and the corpse deposited in the mortuary. Post mortem bone biopsies were done on 10 of the 14 bodies whose relations gave consent for the post mortem after obtaining consent from relations.

40 patients without the exclusion criteria and who did not have the have renal failure but attending out -patient clinic of UBTH, whose ages ranged from 18-65years were used as controls.
