To examine the impact of hypothyroidism on renal function in children and the effect of thyroid hormone therapy on the long-term outcome.Study design
The glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were studied in 31 patients with symptomatic acquired hypothyroidism (age, 11 ± 3.3 years) and in 50 healthy children (age, 10.5 ± 4.5 years). Children with hypothyroidism were examined before starting thyroxine therapy and 1 week and 1, 3, and 6 months after starting thyroxine therapy. 13 patients were reinvestigated at 6, 12, 18, 36, and 60 months after initiating thyroxine therapy.Results
GFR and ERPF were <-2 SD of control levels in 58% and 45%, respectively, of children investigated before or within 1 week after starting thyroxine therapy. 31% and 6% of the children studied 1 to 6 months after thyroxine therapy had a GFR and ERPF <-2 SD. Moreover, when GFR and ERPF values were analyzed as percent of control mean, both measurements were reduced to an equal extent. At the last investigation, 1 to 5 years after start of treatment, the GFR was still significantly lower in children with hypothyroidism than that in control subjects.Conclusion
Acquired hypothyroidism during childhood may have a long-term impact on renal function.