Selecting short-statured children needing growth hormone testing: derivation and validation of a clinical decision
Laëtitia Duché1, Christine Trivin, Wassim Chemaitilly
1Clinical Epidemiological Unit-Department of Pediatrics, Saint-Vincent-de-Paul Hospital, AP-HP, Université Paris Descartes, 75014 Paris, France. laetitia.duche@laposte.net
Insights
A new decision rule can help avoid unnecessary growth hormone (GH) deficiency (GHD) tests in short children. This tool identifies children unlikely to have GHD, reducing unneeded testing and improving diagnostic efficiency.
Area of Science:
- Pediatric Endocrinology
- Growth Disorders
- Diagnostic Accuracy
Background:
- Short stature is common in children, leading to evaluations for growth hormone deficiency (GHD).
- Many GH provocative tests performed are unnecessary as results are often normal.
Purpose of the Study:
- To identify predictors of GHD in short children.
- To develop a sensitive and specific tool to reduce unnecessary GH provocative testing.
Main Methods:
- Retrospective cohort study of 167 children with short stature.
- GHD defined by GH peaks < 10 ng/ml; certain GHD included pituitary stalk interruption.
- Uni- and multivariate analyses identified predictors; a decision rule was created and validated.
Main Results:
- GHD was present in 22% of patients; certain GHD in 3%.
- Predictors of GHD included growth rate < -1 DS, IGF-I < -2 DS, and BMI z-score ≥ 0.
- A decision rule (growth rate < -1 DS and IGF-I < -2 DS) showed 100% sensitivity for certain GHD and 63% for GHD, with 68% specificity.
Conclusions:
- A highly sensitive decision rule was developed and internally validated.
- This rule could potentially avoid over two-thirds of unnecessary GH tests.
- External validation is recommended before clinical application.
Background:
Numerous short-statured children are evaluated for growth hormone (GH) deficiency (GHD). In most patients, GH provocative tests are normal and are thus in retrospect unnecessary.
Methods:
A retrospective cohort study was conducted to identify predictors of growth hormone (GH) deficiency (GHD) in children seen for short stature, and to construct a very sensitive and fairly specific predictive tool to avoid unnecessary GH provocative tests. GHD was defined by the presence of 2 GH concentration peaks < 10 ng/ml. Certain GHD was defined as GHD and viewing pituitary stalk interruption syndrome on magnetic resonance imaging. Independent predictors were identified with uni- and multi-variate analyses and then combined in a decision rule that was validated in another population.
Results:
The initial study included 167 patients, 36 (22%) of whom had GHD, including 5 (3%) with certain GHD. Independent predictors of GHD were: growth rate < -1 DS (adjusted odds ratio: 3.2; 95% confidence interval [1.3-7.9]), IGF-I concentration < -2 DS (2.8 [1.1-7.3]) and BMI z-score > or = 0 (2.8 [1.2-6.5]). A clinical decision rule suggesting that patients be tested only if they had a growth rate < -1 DS and a IGF-I concentration < -2 DS achieved 100% sensitivity [48-100] for certain GHD and 63% [47-79] for GHD, and a specificity of 68% [60-76]. Applying this rule to the validation population (n = 40, including 13 patients with certain GHD), the sensitivity for certain GHD was 92% [76-100] and the specificity 70% [53-88].
Conclusion:
We have derived and performed an internal validation of a highly sensitive decision rule that could safely help to avoid more than 2/3 of the unnecessary GH tests. External validation of this rule is needed before any application.
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