Vitamin D Deficiency and Hypertension in Pediatric Kidney Transplant Patients: Could We Be Doing More?

K. Twombley,² O. Moussa.¹

¹Pathology, Medical University of South Carolina, Charleston
²Pediatrics, Medical University of South Carolina, Charleston, SC.

Meeting: 2015 American Transplant Congress

Abstract number: D214

Keywords: Hypertension, Pediatric

Introduction and Objective: 50-80% of pediatric kidney transplant patients have hypertension (HTN). HTN is a known risk factor for decreased allograft function and survival in children post kidney transplantation. 25-Vitamin D plasma levels [25(OH)D] have been shown to inversely correlate with blood pressure (BP). Data looking at the associations between 25(OH)D and HTN in pediatric kidney transplant patients is lacking. Our center routinely checks 25(OH)D levels in the post -transplant period and we treat all 25(OH)D levels less than 30ng/ml.

Methods: We performed a retrospective chart review of pediatric kidney transplant patients with 25(OH)D testing performed as standard of care between January 1st, 2012 and September 30th, 2013. Inclusion criteria included any pediatric kidney transplant patient age under 18yrs at the time of 25(OH)D testing who were more than 4 months post-transplant. The average measurement of 3 consecutive clinic visit BPs was used to determine BP.

Results: We first looked at pre-transplant 25(OH)D levels in the children that received a kidney transplant from Oct 1st 2012 until Dec 30th 2013. There were 11 children transplanted during this time. Only 2 (18%) had a 25(OH)D levels more than 30ng/ml. We also looked at the number of BP medications that patients were on at the time that the 25(OH)D levels were drawn. Patients with 25(OH)D levels less than 20ng/ml were on 1.63 meds/patient compared to those with 25(OH)D levels more than 20ng/ml who were only on 0.71 meds/patient (p=0.045). We then looked at 5 patients with low 25(OH)D levels who were started on 25(OH)D therapy and compared their pre and post treatment BPs and the results are shown in Table 1.

Table 1

	ALL(n=5)	Pre-Treatment (n=5)	Post-Treatment (n=5)	P
25(OH)D level (ng/ml)		18.7+/-7.2	53.8+/-12.4	0.0067
SBP (mmHg)		114+/-8.4	108+/-9.6	0.099
DBP (mmHg)		73+/-4.4	66+/-5.2	0.0075
Male	4(80%)
Age at start of Treatment (yrs)	11.1+/- 3.9
Time from Transplant at start of treatment (yrs)	4.6+/-3.9

Conclusion: 25(OH)D replacement appears to be beneficial in our small cohort. There needs to be larger studies conducted to evaluate the potential benefits on 25(OH)D supplementation in this unique population. 25(OH)D D supplementation is cheap and easily available. Considering that the majority of pediatric kidney transplant patients are deficient in this vitamin, supplementation could potentially benefit a large number of patients.

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