Nocturnal urinary growth hormone excretion in growth hormone-deficient children on and off growth hormone treatment

Non-compliance has been reported as a major issue in growth hormone (GH) therapy. We explored the use of urinary GH (uGH) measurements to monitor the GH treatment of 18 children (aged 5–16 years) diagnosed as GH deficient on the basis of history, phenotype, auxology and peak GH concentration during 2 provocation tests of <15 mU/l. Each child collected 5 consecutive overnight urine samples while on GH replacement schedules, then discontinued treatment for 2 days and collected a further 5 urine samples. The mean mass of uGH excreted on treatment (8.6 ng, range 3.6–13.0 ng) was significantly greater than that off treatment (1.2 ng, range 0.6–2.7 ng; p <0.01). All uGH values on treatment exceeded the mean nocturnal uGH excretion of normal age- and sex-matched children. The clear distinction between uGH levels on and off GH treatment indicates that uGH measurement would determine whether two or more GH injections had been missed. A series of uGH estimates over a 2-week period may provide a realistic perspective on injection frequency.