Abstract
In Japan, GH treatment (GHT) is used for short stature associated with small for gestational age (SGA), Noonan syndrome (NS), Turner syndrome (TS), achondroplasia (ACH), and hypochondroplasia (HCH). However, real-world data on these diagnoses and GHT use for these conditions in Japan remain limited. In this retrospective cohort study, we used the JMDC claims database (2005-2021) to extract data of children with SGA-related short stature or diagnosed with short stature diseases, namely NS, TS, ACH, or HCH, particularly in boys aged <17 years and girls aged <15 years. We reported the prevalence, comorbidities, age at diagnosis, time from diagnosis to treatment initiation, persistence to GHT, and proportion of days covered (PDC). We analyzed data from children with SGA-related short stature (n = 786), NS (n = 79), TS (n = 172), ACH (n = 107), and HCH (n = 30); the mean (standard deviation) age at initial diagnosis was 5.2 (3.5), 4.0 (4.0), 6.5 (4.2), 3.0 (4.1), and 4.5 (3.9) years, respectively. The prevalence (per 100,000) was 59.59, 5.45, 9.52, 8.31, and 2.12 for SGA-related short stature, NS, TS, ACH, and HCH, respectively. Mean PDC for SGA-related short stature, NS, TS, ACH, and HCH was 0.918, 0.984, 0.953, 0.941, and 1.000, respectively, demonstrating high persistence to GHT. This study provides insights into the current diagnosis and GHT use among children with short stature in Japan. The findings suggest that most Japanese children continue and adhere well to GHT. However, continued efforts toward early referral and diagnosis remain crucial.