Congenital Hypothyroid Screening among Low Birth Weight Infants, Michigan, 2005-2007   Steven J. Korzeniewski, MA, MSc, Ma...
Outline <ul><li>Brief overview of thyroid function and rationale for NICU protocol  </li></ul><ul><li>NICU screening algor...
Hypothalamic-pituitary-thyroid axis  <ul><li>T 4  is stimulated by secretion of TSH by the pituitary.  </li></ul><ul><li>L...
CH Detection in Premature Infants <ul><li>Maturity of the endocrine system influences initial dried blood spot TSH values....
NICU/LBW Screening Algorithm
1:1645 111893 68 1:1410 7050 5 1:211 2961 14 2007 1:1868 42961 23 1:1379 2757 2 1:199 996 5 1/1/08- 5/21/08 1:2283 114136 ...
Number of Infants Screened by Birth Weight, Michigan, 2007   - 100 121,080 91.92 111,291 >=2500g 6,995 8.08 9,789 3.65 4,4...
NICU Protocol Evaluation Conclusions  <ul><li>NICU protocol inclusion criteria currently does not consider gestational age...
Who are we detecting? <ul><li>Is the  10 fold  increase in risk of CH among infants < 1800g  compared to those >= 1800g  r...
CH Three Year Follow-up of ‘ Borderline ’ Cases <ul><li>‘ Borderline’ was initially considered as having pre-treatment ser...
Demographics of Michigan CH Cases Detected by NBS Classified by Pre-Treatment Serum TSH/FT4 Values, 9/2003-9/2007 25.8 58 ...
 
Preliminary Findings of the CH Three year follow-up study <ul><li>Preliminary findings indicate: </li></ul><ul><ul><li>47%...
Overall Conclusions <ul><li>Newborn screening at 24-36hrs of life does not detect children with CH having late rising TSH ...
Acknowledgements <ul><li>Bill Young, Manger, Newborn Screening Follow-up Program </li></ul><ul><li>Violanda Grigorescu, Di...
Thank You [email_address] http://www.michigan.gov/mchepi
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Congenital Hypothyroid Screening among Low Birth Weight Infants

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Congenital Hypothyroid Screening among Low Birth Weight Infants

  1. 1. Congenital Hypothyroid Screening among Low Birth Weight Infants, Michigan, 2005-2007 Steven J. Korzeniewski, MA, MSc, Maternal & Child Health Epidemiology Section Manager Violanda Grigorescu, MD, MSPH, William I. Young, Ph.D. Bureau of Epidemiology, Division of Genomics, Perinatal Health and Chronic Disease Epidemiology
  2. 2. Outline <ul><li>Brief overview of thyroid function and rationale for NICU protocol </li></ul><ul><li>NICU screening algorithm </li></ul><ul><li>Pre-Post NICU algorithm CH detection by birth weight </li></ul><ul><li>Concerns & discussion of newly detected cases (implications of three-year follow-up) </li></ul><ul><li>Conclusion/Public Health implications </li></ul>
  3. 3. Hypothalamic-pituitary-thyroid axis <ul><li>T 4 is stimulated by secretion of TSH by the pituitary. </li></ul><ul><li>Low T 4 (negative feedback) causes hypothalamus to secrete thyrotropin releasing hormone (TRH) which stimulates release of TSH thereby stimulating the thyroid gland to increase secretion of T 4 . </li></ul><ul><li>When the thyroid does not respond to TSH stimulation (primary CH), due to dysgenesis or dyshormonogenesis, the result is low T 4 and high TSH. </li></ul>Hypothalamus Pituitary Gland Thyroid (-) inhibition (+) stimulation TSH + T3, T4 - TRH + T3, T4 -
  4. 4. CH Detection in Premature Infants <ul><li>Maturity of the endocrine system influences initial dried blood spot TSH values. </li></ul><ul><ul><li>Some premature infants with CH have late rising TSH and are therefore not detectable by an initial screen at 24-36hrs of life </li></ul></ul><ul><li>NICU/LBW screening protocol implemented (2007) to account for unreliable screens in premature newborns </li></ul>
  5. 5. NICU/LBW Screening Algorithm
  6. 6. 1:1645 111893 68 1:1410 7050 5 1:211 2961 14 2007 1:1868 42961 23 1:1379 2757 2 1:199 996 5 1/1/08- 5/21/08 1:2283 114136 50 1:1460 7300 5 1:698 2793 4 2006 1:1863 108052 58 1:764 6873 9 1:517 2587 5 2005 Rate Screened Cases Rate Screened Cases Rate Screened Cases > 2500g 1800-2499g < 1800g Birth Weight Birth Year CH Cases by Birth Weight & Birth Year, Michigan, 1/1/2005-5/21/2008
  7. 7. Number of Infants Screened by Birth Weight, Michigan, 2007   - 100 121,080 91.92 111,291 >=2500g 6,995 8.08 9,789 3.65 4,422 2200-2499g 2,573 4.43 5,367 1.28 1,554 2000-2199g 1,019 3.15 3,813 0.84 1,019 1800-1999g   - 2.31 2,794 2.31 2,794 < 1800g Estimated Number of Infants Added to the NICU Protocol (Cumulative) Cumulative % Cumulative Frequency % Frequency Birth Weight
  8. 8. NICU Protocol Evaluation Conclusions <ul><li>NICU protocol inclusion criteria currently does not consider gestational age. </li></ul><ul><ul><li>GA is thought to be a better indicator of maturity than BW; however, concerns about data quality have led the latter to be used. </li></ul></ul><ul><ul><li>Adding very preterm and below (GA < 32 wks) infants would add 215 infants based on 2007 data. </li></ul></ul><ul><li>We are evaluating the impact of: </li></ul><ul><ul><li>increasing the birthweight inclusion criterion to ~2300g, </li></ul></ul><ul><ul><li>adding very preterm and below (GA < 32 wks) infants, and </li></ul></ul><ul><ul><li>eliminating 2 nd screens for infants born weighing less than ~1,000g-1,500g. </li></ul></ul><ul><li>Clinical Laboratory Standards Institute (CLSI) has a subcommittee working on a proposed standard for NBS of SCBU/NICU infants </li></ul>
  9. 9. Who are we detecting? <ul><li>Is the 10 fold increase in risk of CH among infants < 1800g compared to those >= 1800g real ? </li></ul><ul><li>Standard of care is to follow-up CH cases until at least age three years (AAP Guidelines) </li></ul><ul><li>Diagnostic verification recommended (permanent vs. transient CH) </li></ul><ul><ul><li>Thyroid function trial </li></ul></ul><ul><li>Rate and outcome of diagnostic verification unknown </li></ul>
  10. 10. CH Three Year Follow-up of ‘ Borderline ’ Cases <ul><li>‘ Borderline’ was initially considered as having pre-treatment serum TSH values below the 15 Th percentile. </li></ul><ul><ul><li>We recently expanded our criteria to include cases below the 25th percentile and now plan to follow all cases to age 3 years. </li></ul></ul><ul><li>Survey developed and pilot tested in collaboration with PEAC endocrinologists </li></ul><ul><li>Medical management data maintained by NBS Follow-up program used to locate cases’ physicians. </li></ul><ul><ul><li>LTFU mitigated by use of MCIR and phone based survey </li></ul></ul>
  11. 11. Demographics of Michigan CH Cases Detected by NBS Classified by Pre-Treatment Serum TSH/FT4 Values, 9/2003-9/2007 25.8 58 53.1 3001 38.5 30.43% 70 FT4 >=.9, TSH <40 55.6 66.7 50 2461 34.1 3.91% 9 FT4 < .9, TSH < 40 18.2 33.3 61.5 3254 38 20.87% 48 FT4 >=.9, TSH >=40 19.6 39.2 79.1 3156 37.9 44.78% 103 FT4 < .9, TSH >=40 NICU (%) Male (%) White (%) Mean BW Mean GA % N Classification
  12. 13. Preliminary Findings of the CH Three year follow-up study <ul><li>Preliminary findings indicate: </li></ul><ul><ul><li>47% (9/19) of cases with completed diagnostic re-evaluation to date appear not to have permanent CH. </li></ul></ul><ul><ul><li>A surprising number of patients (families) have stopped treatment of their own accord (7/23 with completed follow-up); this phenomenon requires further study. </li></ul></ul><ul><ul><ul><li>One case (family) described miscommunication with health care provider and lack of follow-up as impetus to treatment cessation. </li></ul></ul></ul><ul><ul><li>While all patients who stopped treatment on their own are thought to be transient CH (confirmation of transient CH is pending TSH value receipt- two patients have provided such confirmation to date), only 2/12 cases evaluated by an endocrinologist/hcp are considered transient. </li></ul></ul><ul><ul><ul><li>This finding may have implications for the method of diagnostic re-evaluation. </li></ul></ul></ul><ul><ul><ul><li>Some cases were confirmed based on increasing treatment dosage at approximately 6 months of age; should this preclude three year thyroid challenge? </li></ul></ul></ul><ul><ul><ul><li>Questions remain about process and outcome of three year CH re-evaluation. </li></ul></ul></ul>
  13. 14. Overall Conclusions <ul><li>Newborn screening at 24-36hrs of life does not detect children with CH having late rising TSH </li></ul><ul><li>NICU screening protocols increase CH detection significantly </li></ul><ul><li>It is possible that some moderately LBW children having CH and late rising TSH remain undetected. </li></ul><ul><li>NICU algorithm inclusion criteria require further evaluation </li></ul><ul><ul><li>Gestational age should likely be considered </li></ul></ul><ul><li>It is possible that many borderline cases, which likely includes children with CH detected by the 2 nd or 3 rd screen, are transient </li></ul><ul><ul><li>Such cases are more likely to be male, LBW, NICU births, and/or racial minorities </li></ul></ul><ul><li>Three year follow-up is of critical importance to differentiate transient from permanent CH, particularly in states conducting routine second screens or having NICU/LBW protocols. </li></ul>
  14. 15. Acknowledgements <ul><li>Bill Young, Manger, Newborn Screening Follow-up Program </li></ul><ul><li>Violanda Grigorescu, Director, Division of Genomics, Perinatal Health & Chronic Disease Epidemiology </li></ul><ul><li>Newborn Screening Follow-up Staff </li></ul><ul><li>Pediatric Endocrine Advisory Committee </li></ul>
  15. 16. Thank You [email_address] http://www.michigan.gov/mchepi

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