Evaluation of the congenital hypothyroidism screening programme in Iran: a 3-year retrospective cohort study.

Objective: To evaluate the newborn screening programme for congenital hypothyroidism (CH) in Iran from diagnosis to management and follow-up for 3 years from 2011 to 2014.

Design: Retrospective cohort.

Setting And Patients: Seventeen university districts were randomly selected from 30 provinces. Central data in each district were gathered and collectively analysed. Congenital hypothyroid subjects were followed for 3 years.

Main Outcome Measures: Programme coverage, screening and treatment age, recall rate, compliance to follow-ups.

Results: The total number of births in 2011 was 501 726, of which 452 918 neonates (90.3%) were screened and 15 671 (3.46%) were recalled; 1085 (1:462, 0.22%) were confirmed as having CH (57.1%: permanent, 42.9%: transient) and followed for 3 years. Positive predictive value (PPV) for the first screening test was 6.9%. After the second screening, recall rate was reduced to 0.69% and PPV increased to 31.3%. Median age at screening was 6 (3-9) days and for 90.6% of patients treatment was initiated before 40 days of age with a median levothyroxine dosage of 25 µg/day; 131 (13.4%) were lost to follow-up. Mean number of follow-up visits over 3 years was 5.7 (95% CI 5.5 to 5.9) and 23% (n=225) had total compliance to all follow-ups. Median time for thyroid stimulating hormone normalisation was 45 days, 95% CI (41.1 to 48.8).

Conclusion: In Iran, despite well-established protocols of screening and detecting CH subjects, stricter implementation of a structured system for monitoring and surveillance is needed to promote the management of patients and to reduce rates of loss to follow-up. Determining and addressing the causes of high false positive rates must be prioritised.