Congenital Hypothyroidism Screening Program in Iran; a Systematic Review and Metaanalysis

Objective:

Unrecognized congenital hypothyroidism (CH) leads to mental retardation. Newborn screening and thyroid therapy started within 2 weeks of age can normalize cognitive development. In this systematic review, the local results of the national CH screening program in different provinces in Iran are reviewed and evaluated.

Methods:

Literature on the CH screening, the national databases including SID, Medlib, Iran Medex, Magiran as well as international databases including PubMed/Medline, ISI Web of Knowledge and web of science, EMBASE, SCOPUS and Google Scholar. Appraisal was guided by a checklist assessing clarity of aims and research questions. The 95% confidence intervals were calculated by I-square models. Meta regression was introduced to explore the heterogeneity between studies.

Findings:

We identified 25 samples including 1425124 neonates in our country. Data were Meta analyzed using random-effects models, and we found a TSH levels of 19633 babies in the first sampling were greater than the cut-off level (TSH ≥5mIU/L). The pooled recall rate was 0.014 (95 % CI: 0.013 – 0.015). According to Meta analysis the overall incidence of CH was 2/1000 (95% CI: .002 – .002). The incidence of CH did not appear to be increasing over time (P=0.08).

Conclusion:

Considering TSH ≥5mIU/L as a cut-off point for recalling neonates and low positive predictive value (14%) of this point shows that more investigation and research is needed for establishing accurate level of TSH as a criterion for recalling patients.