Risk Factors of Parathyroid Dysfunction in Elderly Patients with Chronic Kidney Disease Undergoing Hemodialysis.

BACKGROUND: Aberrant mineral metabolism and bone diseases, which are commonly seen in chronic kidney disease (CKD), have been considered to be the important causes of morbidity and decreased quality of life.

OBJECTIVES: We aimed to investigate the characteristics of calcium-phosphorus metabolism abnormalities and parathyroid dysfunction in elderly patients with chronic kidney disease undergoing hemodialysis.

MATERIAL AND METHODS: A total of 336 patients undergoing maintenance hemodialysis were divided into two age groups: elderly (≥ 65 years) and non-elderly (< 65 years). Before dialysis, fasting blood samples were initially collected, then hemoglobin (Hb), serum creatinine (Scr), blood urea nitrogen (BUN), calcium, phosphorus, intact parathyroid hormone (iPTH), high-sensitivity C-reactive protein (HsCRP) and albumin (Alb) were measured. Serums BUN, ultrafiltration volume, dialysis duration and body weight were measured after dialysis. Finally, well-established formulas were used to obtain the serum albumin corrected calcium (Ac-Ca) and urea removal index (Kt/V).

RESULTS: Elderly patients accounted for 52.7% of our patients; essential hypertension accounted for 35.6% of the cause for chronic renal failure, followed by chronic glomerulonephritis (21.5%) and diabetes mellitus (19.8%) in the elderly group; while in the non-elderly group, 43.4% of the chronic renal failure was due to chronic glomerulonephritis, followed by diabetes mellitus (23.9%) and essential hypertension (12.6%). Significant differences were found in the dialysis duration, blood pressure, concentrations of serum BUN, Scr, P, iPTH, Alb, standard-protein nitrogen present rate (nPNA) and Hs-CRP between the 2 groups. The multiple logistic regression analysis showed that age, plasma phosphorus, albumin and nPNA were independent risk factors for secondary hyperparathyroidism in patients undergoing maintenance hemodialysis.

CONCLUSIONS: We conclude that most elderly patients undergoing hemodialysis experience hyperparathyroidism. The risk factors may include age and malnutrition but need further investigation.