Bone age and factors affecting skeletal maturation at diagnosis of paediatric Cushing's disease

Paediatric Cushing's disease (CD) is usually associated with growth retardation, but there are only few published data on skeletal maturation at diagnosis. We analysed factors contributing to skeletal maturation and final height in Asian Indian patients with paediatric CD. We conducted retrospective analysis of 48 patients (29 males; 19 females) with mean age: 14.84 years at diagnosis (range 9-19 years). A single observer using the Greulich Pyle method determined the bone age (BA) of each child. BA delay, i.e. the difference between chronological age (CA) and BA, was compared with clinical and biochemical variables. BA delay was present in 35/48 (73%) patients (mean delay 1.6 years, range 0.5-5 years) and correlated negatively with height SDS (r = -0.594, P < 0.001) and positively with CA at diagnosis (r = 0.247, P < 0.05). There was no correlation with duration of symptoms before diagnosis, basal cortisol, midnight cortisol, ACTH or percentage suppression of low dose dexamethasone suppression cortisol (LDDST). We could not demonstrate any relationship between the duration of history before diagnosis and height SDS at final height. Mean final height SDS in patients was -1.84. We found that most children with CD had delayed BA and correlated significantly with CA and height SDS at diagnosis. Early diagnosis may reduce delay in skeletal maturation and thus contribute to optimal catch-up growth.