Amino-terminal propeptide of C-type natriuretic peptide (NTproCNP) predicts height velocity in healthy children.

OBJECTIVE: C-type natriuretic peptide (CNP) is a paracrine regulatory factor of the growth plate and plays a key role in endochondral growth. Its amino-terminal propeptide (NTproCNP) is an equimolar product of CNP biosynthesis and is easily measured in plasma. Preliminary studies suggest that NTproCNP levels correlate with height velocity in sheep and children. The objectives of the study were to correlate NTproCNP levels with height velocity and to define the reference range for plasma CNP and NTproCNP across childhood. DESIGN: This was a prospective, cross-sectional, observational study of healthy children. PATIENTS: Participants were 258 healthy children between 2 months and 20 years of age. MEASUREMENTS: Anthropometrics were obtained and CNP and NTproCNP levels were determined by radioimmunoassay. RESULTS: For both sexes, CNP and NTproCNP levels were high in infancy, lower in early childhood, rising during puberty, then falling to low adult levels. Levels of NTproCNP peaked at 14·1 years in boys and 11·9 years in girls, coincident with the age of peak height velocity. Levels of NTproCNP varied with pubertal status, peaking at genital Tanner stage IV in boys and III in girls. There was a highly significant correlation between NTproCNP and height velocity. CONCLUSIONS: C-type natriuretic peptide plays an integral role in endochondral growth. We show here that CNP synthesis (as measured by NTproCNP levels in plasma) is closely related to linear growth in healthy children at all ages. We propose NTproCNP as a biomarker of linear growth.

Psychometric performance of the Quality of Life in Short Stature Youth (QoLISSY) questionnaire in a randomized open-label comparator trial in idiopathic short stature.

Background In addition to increasing linear growth, improvement in health-related quality of life (HRQOL) is an important endpoint in the treatment of short statured youth. Hence, condition-specific psychometric valid instruments that adequately assess HRQOL are needed. We aimed to confirmatorily examine the psychometric performance of the Quality of Life in Short Stature Youth (QoLISSY) questionnaire used in a previously reported prospective randomized open-label trial. Methods This trial compared treatment of idiopathic short stature (ISS) in 76 adolescent males with either oral aromatase inhibitors (AIs), subcutaneous daily growth hormone (GH) or a combination treatment (AI/GH) for at least 2 years, demonstrating improvements in HRQOL with the GH and AI/GH interventions. HRQOL was assessed from the child's and parent's perspectives with the short stature-specific QoLISSY and the generic KIDSCREEN questionnaires before and 24 months into treatment. Scale scores and psychometric properties were examined regarding reliability and validity of the QoLISSY questionnaire using the dataset from the published trial. Results The QoLISSY questionnaire showed high internal consistency and satisfactory criterion, convergent and known-groups validity. Scale scores were evenly distributed with no major floor or ceiling effects. Responsiveness analyses suggest that the QoLISSY questionnaire detects significant changes in HRQOL after 2 years of treatment with growth-promoting therapies in children with short stature from both the child's and parent's perspectives. Conclusions The QoLISSY questionnaire is a psychometrically sound, reliable and valid instrument that can explore the experiences associated with short stature, track HRQOL changes over time and in response to treatment, and highlight HRQOL domains that can be improved through intervention.

Quality of Life in Adolescent Boys with Idiopathic Short Stature: Positive Impact of Growth Hormone and Aromatase Inhibitors.

BACKGROUND: The combination of growth hormone (GH) and aromatase inhibitors (AI) improves linear growth in severely short adolescent boys; however, the effects of this intervention on quality of life (QoL) are unknown. This study assesses whether GH, AI, or their combination impacts the QoL of adolescent males with idiopathic short stature (ISS) from both the adolescent and the parent perspective. METHOD: A randomized open-label comparator trial was conducted in 76 pubertal males with ISS who received AI, GH, or AI/GH for 24 months. The condition-specific Quality of Life in Short Stature Youth questionnaire was used to assess QoL. RESULTS: QoL scores were low at baseline in the children's and parents' reports. Within-group testing showed that total QoL scores increased significantly at 24 months in the GH and AI/GH group but not the AI group in the children's report, whereas it increased in all of the groups in the parents' report. Increases in QoL scores were associated with an increase in height SDS. CONCLUSIONS: Treatment with GH and AI/GH was associated with improved QoL scores as measured from both the patients' and the parents' perspectives, suggesting that the improved growth resulting from the use of these growth-promoting therapies has beneficial psychosocial effects in adolescent males with ISS followed for 24 months.

Randomized Trial of Aromatase Inhibitors, Growth Hormone, or Combination in Pubertal Boys with Idiopathic, Short Stature.

CONTEXT: Growth of short children in puberty is limited by the effect of estrogen on epiphyseal fusion. OBJECTIVES: To compare: 1) the efficacy and safety of aromatase inhibitors (AIs) vs GH vs AI/GH on increasing adult height potential in pubertal boys with severe idiopathic short stature (ISS); and 2) differences in body composition among groups. DESIGN: Randomized three-arm open-label comparator. SETTING: Outpatient clinical research. PATIENTS: Seventy-six pubertal boys [mean (SE) age, 14.1 (0.1) years] with ISS [height SD score (SDS), -2.3 (0.0)]. INTERVENTION: Daily AIs (anastrozole or letrozole), GH, or AI/GH for 24-36 months. OUTCOMES: Anthropometry, bone ages, dual x-ray absorptiometry, spine x-rays, hormones, safety labs. RESULTS: Height gain [mean (SE)] at 24 months was: AI, +14.0 (0.8) cm; GH, +17.1 (0.9) cm; AI/GH, +18.9 (0.8) cm (P < .0006, analysis of covariance). Height SDS was: AI, -1.73 (0.12); GH, -1.43 (0.14); AI/GH, -1.25 (0.12) (P < .0012). Those treated through 36 months grew more. Regardless of treatment duration, height SDS at near-final height [n = 71; age, 17.4 (0.2) years; bone age, 15.3 (0.1) years; height achieved, ∼97.6%] was: AI, -1.4 (0.1); GH, -1.4 (0.2); AI/GH, -1.0 (0.1) (P = .06). Absolute height change was: AI, +18.2 (1.6) cm; GH, +20.6 (1.5) cm; AI/GH, +22.5 (1.4) cm (P = .01) (expected height gain at -2.0 height SDS, +13.0 cm). AI/GH had higher fat free mass accrual. Measures of bone health, safety labs, and adverse events were similar in all groups. Letrozole caused higher T and lower estradiol than anastrozole. CONCLUSIONS: Combination therapy with AI/GH increases height potential in pubertal boys with ISS more than GH and AI alone treated for 24-36 months with a strong safety profile.