The Effect of Combined Calcium and Vitamin D3 Supplementation on Serum Intact Parathyroid Hormone in Moderate CKD

Kooienga, Laura; Fried, Linda; Scragg, Robert; Kendrick, Jessica; Smits, Gerard; Chonchol, Michel

doi:10.1053/j.ajkd.2008.09.020

« Previous Next »American Journal of Kidney Diseases
Volume 53, Issue 3 , Pages 408-416, March 2009

The Effect of Combined Calcium and Vitamin D₃ Supplementation on Serum Intact Parathyroid Hormone in Moderate CKD

Laura Kooienga, MD
- Division of Renal Diseases and Hypertension, University of Colorado Health Sciences Center, Denver, CO
Linda Fried, MD, MPH
- Veterans Affairs Pittsburgh Healthcare System, University of Pittsburgh School of Medicine, Pittsburgh, PA
Robert Scragg, PhD
- School of Population Health, Epidemiology and Biostatistics Section, University of Auckland, Auckland, New Zealand
Jessica Kendrick, MD
- Division of Renal Diseases and Hypertension, University of Colorado Health Sciences Center, Denver, CO
Gerard Smits, PhD
- Division of Renal Diseases and Hypertension, University of Colorado Health Sciences Center, Denver, CO
Michel Chonchol, MD
- Division of Renal Diseases and Hypertension, University of Colorado Health Sciences Center, Denver, CO
- Address correspondence to Michel B. Chonchol, MD, University of Colorado Health Sciences Center, Division of Renal Diseases and Hypertension; Box C-280, Denver, CO 80262

Received 9 April 2008; accepted 4 September 2008. published online 30 January 2009.

Background

Studies addressing the effects of vitamin D₃ supplementation on secondary hyperparathyroidism in patients with moderate chronic kidney disease are scarce.

Study Design

Post hoc analysis of the randomized clinical trial Vitamin D, Calcium, Lyon Study II (DECALYOS II) to assess effects according to baseline estimated glomerular filtration rate (eGFR).

Setting & Participants

Multicenter, randomized, double-blinded, placebo-controlled study of 639 elderly women randomly assigned to calcium–vitamin D₃ fixed combination; calcium plus vitamin D₃ separate combination, or placebo.

Interventions

Placebo or calcium (1,200 mg) and vitamin D₃ (800 IU) in fixed or separate combination.

Outcomes & Measurements

Proportion of participants with a mean decrease in intact parathyroid hormone (iPTH) level of 30% or greater. eGFR was calculated using the 4-variable Modification of Diet in Renal Disease (MDRD) Study equation and categorized as 60 or greater, 45 to 59, and less than 45 mL/min/1.73 m².

Results

610 participants had an eGFR at baseline: 288 (47.2%), 222 (36.4%), and 100 (16.4%) were in each decreasing eGFR category. Across decreasing eGFR groups, 88%, 86%, and 89% had 25-hydroxyvitamin D (25[OH]D) levels less than 15 ng/mL at baseline. On treatment, similar improvements in the proportion of participants achieving 25(OH)D levels greater than 30 ng/mL at 6 months were seen in all kidney function groups (43%, 49%, and 41%, respectively). Active regimens versus placebo increased mean 25(OH)D levels from baseline in all eGFR groups at all times (P < 0.001 for all). The proportion with a 30% or greater decrease in iPTH level at 6 months was 50% in all eGFR groups on treatment versus 6% to 9% for placebo (P < 0.001 for all). The effects of the intervention on iPTH levels did not differ according to baseline eGFR (interaction P > 0.1 for all times).