Preterm Infants and Nephrocalcinosis (NC)

Preterm Infants and Nephrocalcinosis: Diagnosis and Pathogenesis

Nephrocalcinosis (NC), defined as calcification of renal tissue, has been reported to occur in 7-41% of premature infants. Causes of NC are likely multi-factorial, and infants born prematurely and with very low birth weight (<1500 gm) seem to be at the highest risk of developing NC. Recent changes in recommendations for nutrition for the preterm infant such as higher intakes of protein, calcium, and vitamin D may also play a factor in the pathogenesis of NC.

Currently, diagnosis of NC often occurs incidentally during ultrasound evaluation for other issues. Because there is no acute symptom or pattern of symptoms in the preterm population associated specifically with NC, it is possible that many cases of NC may not be diagnosed. Presently, it is impractical and costly to screen all infants for NC with renal ultrasound, therefore there is no standard of care regarding screening for NC.

NC may have long-term effects. Studies have shown that preterm infants with NC had shorter kidneys and a lower rate of tubule resorption of phosphorus (TRP) than preterm infants without NC.

This study will analyze weekly urinalysis for all enrolled subjects prospectively and then look at the incidence of NC at discharge of the enrolled subjects.

Study Overview

• Status: Completed
• Conditions: Prematurity; Hypercalciuria; Nephrocalcinosis

• Study Type: Observational
• Enrollment (Actual): 56

Contacts and Locations

Study Locations

• United States
  • Utah
    • Murray, Utah, United States, 84157
      • Intermountain Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: No older than 1 year (Child)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

Infants admitted to the newborn intensive care unit.

Description

Inclusion Criteria:

• Infants whose gestation less than or equal to 32 weeks and/or birth weights less than 1800 gm

Exclusion Criteria:

• Infants with congenital abnormalities of the heart, lung, GI, or kidneys that will affect renal function.

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Non-NC group; Enrolled subjects who did not have evidence of NC on renal ultrasound
NC group; Enrolled subjects who did have evidence of NC on renal ultrasound

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Urinary calcium to creatinine ratio (UCa/Cr)	Beginning within the first two weeks of life, urine calcium to creatinine ratio (UCa/Cr) will be analyzed weekly through discharge and then correlated to renal ultrasound results done prior to discharge.	3 months
Urinary crystals	Beginning within the first two weeks of life, urinalysis for evidence of urinary crystallization will be analyzed weekly through discharge and then correlated to renal ultrasound results done prior to discharge.	3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Serum Vitamin D levels	Serum vitamin D levels will be analyzed and compared in infants with NC against infants without NC (controls).	3 months
Vitamin D intake	Daily vitamin D intake will be recorded from participants' medical records and will be analyzed and compared in infants with NC against infants without NC (controls).	3 months
Calcium intake	Daily calcium intakes will be recorded from participants' medical records and will be analyzed and compared in infants with NC against infants without NC (controls).	3 months
Protein intake	Daily protein intakes will be recorded from participants' medical records and will be analyzed and compared in infants with NC against infants without NC (controls).	3 months
Total bone density per DXA	Whole body bone density per dual energy X-ray absorptiometry (DXA) will be done on all enrolled participants at discharge and will be compared between infants with and without NC.	3 months
Tibial bone density per tibial ultrasound	Tibial body bone density per ultrasound will be done on all enrolled participants at discharge and will be compared between infants with and without NC.	3 months

Collaborators and Investigators

• Sponsor: University of Utah
• Collaborators: Intermountain Health Care, Inc.
• Investigators: Principal Investigator: Sabrina Malone-Jenkins, MD, University of Utah

Study record dates

Study Major Dates

• Study Start: April 1, 2015
• Primary Completion (Actual): January 1, 2017
• Study Completion (Actual): January 1, 2017

Study Registration Dates

• First Submitted: May 1, 2015
• First Submitted That Met QC Criteria: May 5, 2015
• First Posted (Estimate): May 8, 2015

Study Record Updates

• Last Update Posted (Actual): March 13, 2017
• Last Update Submitted That Met QC Criteria: March 9, 2017
• Last Verified: June 1, 2016

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Metabolic Diseases; Kidney Diseases; Urologic Diseases; Urological Manifestations; Calcium Metabolism Disorders; Calcinosis; Hypercalciuria; Nephrocalcinosis
• Other Study ID Numbers: 66906