Vitamin D levels and patient outcome in chronic kidney disease

Area of Science:

• Nephrology
• Endocrinology
• Cardiovascular Medicine

Background:

• Vitamin D deficiency is linked to adverse outcomes in hemodialysis patients.
• The association between vitamin D levels and outcomes in earlier stages of chronic kidney disease (CKD) is not well-established.

Purpose of the Study:

• To investigate the relationship between plasma 25-hydroxyvitamin D levels and clinical outcomes in patients with stages 2-5 CKD.
• To determine if vitamin D deficiency predicts disease progression and mortality in non-dialysis CKD patients.

Main Methods:

• Prospective cohort study of 168 new CKD clinic referrals (eGFR stage 2 or less).
• Patients were followed for up to 6 years for initiation of dialysis or death.
• Baseline 25-hydroxyvitamin D levels were measured and correlated with clinical outcomes using Cox's models, adjusting for multiple covariates.

Main Results:

• Baseline 25-hydroxyvitamin D levels directly correlated with estimated glomerular filtration rate (eGFR).
• After a median follow-up of 48 months, 48 patients started dialysis and 78 died.
• Plasma 25-hydroxyvitamin D was an independent inverse predictor of both time to death and end-stage renal disease (ESRD).

Conclusions:

• Plasma 25-hydroxyvitamin D is an independent predictor of adverse outcomes in patients with stages 2-5 CKD.
• Maintaining adequate vitamin D levels may be important for slowing CKD progression and improving survival.