Supplementary Material for: Growth hormone therapy: Comparison of short- and long-term outcomes between children with Growth Hormone Deficiency and Small for Gestational Age

Introduction Direct comparisons of both short-term and long-term auxological outcome of growth hormone therapy (GHT) between growth hormone deficiency (GHD) and small for gestational age (SGA) are scarce. Methods 103 patients with GHD and 53 patients with SGA treated at our tertiary center were investigated. Short-term and long-term outcomes were compared between these groups using multi-variable linear regression models with adjustment for age, sex and height at therapy start, also allowing for sex-specific group comparisons. Results Mean delta height standard deviation scores (SDS) after 1 year of treatment was significantly higher in GHD (0.90, CI 0.82 to 0.99) compared to SGA (0.67, C I 0.54 to 0.79)(p= 0.003) with no sex difference. As expected, the mean increase in height SDS at final height (FH) was significantly higher in GHD (2.21, CI 2.00 to 2.42) compared to SGA (1.05, CI 0.75 to 1.35)(p<0.001), leading to a target height corrected FH of -0.39 SDS (CI -0.62 to -0.15) in GHD and -1.22 SDS (CI-1.57 to -0.87) in SGA ( p<0.001). Girls with GHD had a better long-term outcome, as did boys with SGA when compared to the respective opposite sex. The cut-off of delta height of 0.5 SDS during the first year had a low sensitivity to detect long-term non-responders. We found a relation between short-term and long-term outcome in GHD, but not in SGA (adjusted R2 = 0.66 vs. 0.01). Conclusion In contrast to GHD, we observed practically no relationship between 1st-year and long-term outcome in SGA patients treated with GH.