Growth in children with pulmonary arterial hypertension: a longitudinal retrospective multiregistry study.

BACKGROUND: To enable adequate interpretation of growth measurements in the management of children with pulmonary arterial hypertension (PAH), we assessed growth and its associated determinants in children with PAH. METHODS: We did a retrospective longitudinal study of height and body-mass index in reference to WHO growth standards by pooling data from four contemporary prospective registries of paediatric PAH representing 53 centres in 19 countries. The main outcome measures were median height for age and body-mass index for age percentiles and longitudinal deviation of height for age and body-mass index for age Z scores from WHO standards. FINDINGS: 601 children were followed up for a median of 2·9 years (IQR 1·5-4·4). Baseline median height for age percentile was 26 (IQR 4-54) and baseline median body-mass index for age percentile was 41 (IQR 12-79). Mean height for age Z score was significantly lower than the reference (-0·81, 95% CI -0·93 to -0·69; p<0·0001), as was body-mass index for age Z score (-0·12, -0·25 to -0·01; p=0·047). Height for age Z score was particularly decreased in young patients (aged ≤5 years) with idiopathic or hereditary PAH and in all patients with PAH associated with congenital heart disease. Although Z scores increased in some patients and decreased in others, we detected no significant trend in height for age Z score (p=0·57) or body-mass index for age Z score (p=0·48) before taking account of covariates. Multivariable linear mixed effects modelling showed that age, cause of PAH, ex-prematurity, WHO functional class, trisomy 21, and time since diagnosis were associated with height for age Z score, whereas age, ethnicity, and trisomy 21 were associated with body-mass index for age Z score. A favourable WHO functional class course was independently associated with increases in height for age Z score. INTERPRETATION: PAH is associated with impaired growth, especially in younger children and those with pulmonary arterial hypertension associated with congenital heart disease. The degree of impairment is independently associated with cause of PAH and comorbidities, but also with disease severity and duration. Because a favourable clinical course was associated with catch-up growth, height for age could serve as an additional and globally available clinical parameter to monitor patients' clinical condition. FUNDING: Actelion Pharmaceuticals.