Adult height in congenital hypothyroidism: prognostic factors and the importance of compliance with treatment.

Objective: To study the growth, puberty and compliance of 66 hypothyroid children and to determine prognostic factors for adult height.

Patients: 66 children were included (12 boys, 54 girls). Aetiologies were 43 ectopic glands, 14 thyroid agenesis, 9 dyshormonogenesis.

Results: In girls the mean adult height was 164.7 +/- 6.5 cm for a target height (TH) of 162.8 +/- 5.4 cm. In boys the mean adult height was 178.2 +/- 6.4 cm for a TH of 175.7 +/- 4.7 cm. Puberty development was normal. Children who exceeded their TH had an earlier start of treatment versus children who failed to reach their TH: 24.8 +/- 13.5 vs. 42.0 +/- 47.3 days, p = 0.004. Delayed normalisation of TSH is a risk factor for bad compliance. Adequate correlations between treatment variables appeared only in children who exceeded their TH.

Conclusions: TH, day of start of treatment and compliance with treatment are the main prognostic factors for adult height. Early detection of bad compliance is possible.