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

Abstract

ObjectiveTo 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.DesignRetrospective cohort.Setting and patientsSeventeen 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 measuresProgramme coverage, screening and treatment age, recall rate, compliance to follow-ups.ResultsThe 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).ConclusionIn 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.