Serum vitamin D and parathyroid hormone profiles in patients with various stages of renal disease

Background The prevalence of vitamin D deficiency among Saudi population has increased recently. The social and pathological factors, including kidney disease that may have influenced the vitamin status have not been investigated in the Hail population. Aims The present study aims to: (1) investigate changes in the serum vitamin D, parathyroid hormone, serum calcium, and phosphate levels in Saudi patients with kidney disease; and (2) elucidate the other possible physiological factors that may have influence on the vitamin status. Methods A cross-sectional study was carried out in King Khalid Hospital in Hail, Saudi Arabia. The database of kidney disease patients that attended the Kidney Unit between September 2012 and June 2013 was searched and data classified according to the estimated glomerular filtration rate into stages 1-4. Beside the kidney function parameters, serum calcium, phosphorus, vitamin D, and parathyroid hormone were measured. Results Out of the 167 patients who visited the kidney unit, the data of 96 patients was included in the study. The results exhibited significant reductions in serum vitamin D level in stage 4 patients by 52.05 per cent with significant increase in the serum PTH level amounting to 3.5-fold. Kidney impairment at stage 4 caused significant increase in the serum phosphate level by 15.74 per cent and the serum calcium by 8.17 per cent. Significant correlations were observed between serum creatinine and Log PTH (r=0.704, p<0.0001) and a negative correlation between creatinine and log vitamin D (r=-0.373, p=0.001). Conclusion The results exhibited depletion of serum vitamin D concentration accompanied with the development of severe secondary hyperparathyroidism with the progression in kidney disease. The vitamin D deficiency was more prominent in females, older ages, and advanced kidney disease.