Recall rate and incidence of congenital hypothyroidism: A 5-year experience of hospital-based study in Bahrain

Background: Different neonatal screening programs for congenital hypothyroidism (CH) have been implemented to prevent its devastating effects on mental development. High recall rate and false positive results subject families to undue stress and impose financial burdens on health care expenditures. Objective: to investigate the CH recall rate and establish an optimum cord blood thyroid-stimulating hormone (CBTSH) level for CH diagnosis. Methods: retrospective cross-sectional study was conducted in Bahrain Defense Force hospital from Jan 2012 to Dec 2016. CBTSH and back-up free thyroxine (T4) results from all newborn infants born during this period were analyzed. All of the infants with CBTSH >37.5 μIU/ml were recalled for confirmatory tests. Results: Out of 20,885 newborns, 413 infants were recalled (recall rate 1.98%). CH incidence was 1:1489, mean CBTSH was 99.5 μIU/ml (95% confidence interval (CI) 98.7-100.3 μIU/ ml), and mean free T4 was 9.1 pmol/l (95% CI, 6.64-11.57 pmol/l). A receiver operating characteristic (ROC) curve identified the new CBTSH cutoff value as 93 μIU/ml. Conclusion: Our study supports setting a higher CBTSH cutoff value based on our population findings and recommends both CBTSH and simultaneous free cord T4 measurements as the ideal screening approach