Blood pressure (BP) status in Congenital Adrenal Hyperplasia (CAH) - longitudinal analysis of real world data from the I-CAH registry

Abstract

Introduction: Data on BP in children with classic congenital adrenal hyperplasia (CAH) is inconsistent. Aim: To assess the trend in BP throughout childhood using data from the International CAH registry and compare this to nor mative data from the American Academy of Paediatrics (AAP). Method: This retrospective multi-centre study included 37 centres from 20 countries. BP data was analysed by Lambda Mu-Sigma (LMS) modelling to create smoothing reference curves. We subtracted the AAP median BP for age from the I-CAH regis try median BP for age, and conducted Bayesian multiple change point analysis to assess the age at which BP in the two populations converged. Results: A total of 546 patients (53% girls, 86% prescribed Fludrocortisone) with 6357 visits between 1988-2021 were avail able for analysis and 3181 visits had BP measurements available. Each centre contributed a median of 12 patients (Interquartile Range (IQR) 5, 23), with data from a median of 6.0 years (IQR 3.2, 12.7) follow up per patient. Median age at visit was 5.4 years (IQR 2.4, 10.6), maximum age at visit was 19.9 years, and median num ber of visits available per patient was 5 (IQR 2, 9). When compared against AAP normative BP values, the differ ence in median BP for age decreased with a clear plateau in both sexes. Systolic BP was higher in 1 year old CAH patients by 17.5 mmHg in boys and 13.6mmHg in girls, decreasing to a plateau of 6.2mmHg higher after age 7.7 years in boys and 5.3mmHg after age 13.3 years in girls. Diastolic BP was 22.9mmHg higher in boys and 18.3mmHg higher in girls at the age of 1 year, decreasing to a plateau of 3.2mmHg higher after age 6.7 years in boys and 3.3mmHg higher after age 6.3 years in girls. Conclusions: Analysis of real world data shows BP in children with classic CAH to be higher than normative values at an early age, but to plateau at age 8 years in males and 13 years in females to a level marginally higher than reference values. The difference was greater in diastolic BP at early ages, but greater in systolic BP after plateau. The impact of higher BP at these young ages on vas cular modelling and long term cardiovascular risk in CAH is unknown and warrants further investigation. Further analysis with covariates within this data set is ongoing, seeking to clarify other determinants of BP in CAH.