International Consensus on the Diagnosis and Clinical Management of Idiopathic Short Stature: A Modified Delphi Method.

INTRODUCTION: Idiopathic short stature (ISS) refers to children whose height falls substantially below the mean for sex and age relative to a reference population, despite the absence of an identifiable endocrine, genetic, syndromic, or systemic disorder. Clinical management remains challenging because no dedicated ICD-11 code exists and no universally accepted diagnostic criteria have been established. This has led to variability in how the condition is classified, inconsistency in access to testing, and uncertainty around eligibility for growth-promoting therapies. To address these inconsistencies and support broader global alignment in the recognition and management of ISS, an international consensus initiative was undertaken. METHODS: A Steering Committee of 10 internationally recognized experts with extensive clinical and academic expertise in ISS supported the development of a structured modified Delphi process. An Expert Panel of 22 key opinion leaders participated in a three‑round survey conducted between November 2025 and February 2026. Panelists evaluated draft statements related to ISS definition, diagnostic criteria, burden of disease, and decision to treat. Consensus thresholds were predefined at 70%, and statements were refined between rounds, as needed. RESULTS: A total of 44 statements achieved consensus, with final agreement levels ranging from 77% to 100%. The statements establish a standardized clinical definition of ISS, propose evidence-based diagnostic criteria applicable across diverse healthcare settings, describe the impact of ISS on patients and caregivers, and suggest when to consider growth-promoting treatment for patients with ISS. For example, consensus was reached on the definition of ISS (a condition in which an individual has a height more than a standard deviation score of 2 below the mean for sex, age, and population, corresponding to below the 2.3 percentile, without identifiable underlying pathology) and on key elements of diagnostic evaluation (include the child's medical, developmental, and medication background, including prenatal and perinatal course, chronic illnesses or infections, and neurodevelopmental milestones, alongside family history and environmental exposures; perform a physical examination to identify clinical signs of underlying pathology, including assessment of body proportions, dysmorphic body features, head circumference, body mass index, and pubertal development). Key areas requiring future research were also highlighted. CONCLUSION: This international consensus offers the first globally derived, ISS‑focused guidance developed using a formal Delphi methodology for identifying and managing children and adolescents with ISS. Adoption of these recommendations may reduce regional variability, improve diagnostic clarity, and ultimately enhance outcomes for individuals affected by ISS.