Failure to normalize parathyroid hormone during treatment of vitamin D deficiency in Asian patients.
OBJECTIVE
Vitamin D deficiency and osteomalacia remain commonplace within the Asian community in Bradford. The treatment of vitamin D deficiency and osteomalacia is cheap and effective, but there are few data on long-term outcomes. Studies have suggested that a minority of patients fail to normalize parathyroid hormone (PTH) levels during therapy with vitamin D. This study aimed to determine what proportion of Asian patients with vitamin D deficiency and secondary hyperparathyroidism normalize PTH levels following therapy with oral vitamin D and to examine reasons for failure to normalize PTH.


METHODS
This study examined the impact of an oral regimen of vitamin D 800 i.u. (20 micrograms) and calcium 1000 mg daily, on PTH levels within an endocrinology outpatient clinic. patients 51 (4M:47F) Asian patients, median age 39 years (range 16-77 years) with vitamin D deficiency (25-hydroxyvitamin D < 25 nmol/l) and secondary hyperparathyroidism (PTH > 5.7 pmol/l).


METHODS
All patients had at least one follow-up measurement of PTH and calcium during treatment. A subgroup of patients gave consent for examination of GP-prescribing records to indirectly asses adherence to therapy.


RESULTS
PTH normalized in only 28/51 (55%) patients (group N) and failed to normalize in 23/51 (45%) patients (group F). Baseline patient characteristics including: age, basal serum 25-hydroxyvitamin D (25OHD), basal serum PTH, basal serum calcium and post treatment serum calcium, were similar in groups N and F. Mild hypercalcaemia occurred in only two (3.9%) patients. The proportion of prescriptions collected by patients in group N was 75 (17-100)% and in group F was 17 (0-100)%, P < 0.0001.


CONCLUSIONS
This study has demonstrated that long-term oral treatment with vitamin D and calcium, fails to normalize PTH in a significant proportion of patients with vitamin D deficiency and osteomalacia. This is most likely related to lack of adherence to long-term treatment. Improved ways of treating this condition need to be explored.
Peacey
Steven R
SR
Department of Diabetes and Endocrinology, Bradford Teaching Hospitals NHS Trust, Bradford, UK. srpeacey@talk21.com
Wright
Dianne
D
Harries
Matthew J
MJ
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000368:Aged; D001208:Asia / Q000208:ethnology; D002118:Calcium / Q000008:administration & dosage / Q000097:blood; D004739:England; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D010349:Patient Compliance; D018709:Statistics, Nonparametric; D013997:Time Factors; D017211:Treatment Failure; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use*; D014808:Vitamin D Deficiency / Q000097:blood / Q000188:drug therapy*
D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium