Real-World Evidence of Clinical Outcomes in Patients With Assumed Classic Congenital Adrenal Hyperplasia in the United States
Authors: Farrar Mallory , Farber Robert , Sen Ginny P , Yonan Charles , Chan Jean Lin 
Published: May 2021

Abstract
Background: Classic congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder, usually due to a deficiency in the 21-hydroxylase enzyme, that results in impaired cortisol synthesis and excess androgen production. Patients with classic CAH experience both disease-related features from excess androgens and treatment-related complications from the chronic, supraphysiologic use of glucocorticoids (GCs) often required for androgen control. This study was conducted to evaluate the demographics and clinical characteristics of adult and pediatric patients in the United States (US) with assumed classic CAH based on International Classification of Diseases (ICD) codes, GC prescriptions, and medical claims. Methods: Analyses were based on longitudinal patient-level data from the Decision Resources Group Real World Evidence repository, which links medical claims, prescription claims, and electronic health records from &gt;300 million US patients. Data were analyzed for patients aged ≥18 years (adult) and &lt;18 years (pediatric) with assumed classic CAH based on ICD 9/10 codes associated with “adrenogenital disorders” and whose proportion of days covered with a GC in 2018–2019 was &gt;75%. These patients were matched 1:3 with a control cohort based on age, gender, geographic region, and insurance type. Both assumed CAH and control cohorts had continuous coverage with at least 1 medical claim and 1 pharmacy claim in each year, 2018–2019. Results: Of 1,111 patients with assumed classic CAH, 778 were ≥18 years old (65% female; mean age [±SD], 43±17 years) and 333 were &lt;18 years old (51% female; mean age [±SD], 11±4.7 years). Both adult and pediatric patients with assumed classic CAH were more likely than matched controls (adult N=2334; pediatric N=999) to experience events that could be related to chronic GC use, including infection (adult: 49.9% vs 37.3% [control]; pediatric: 49.5% vs 40.0%), weight gain (adult: 5.9% vs 2.5%; pediatric: 9.0% vs 2.6%), and moon face (adult: 44.0% vs 0.1%; pediatric: 37.8% vs 0.1%); all P&lt;0.01 vs control. Adult patients were more likely than matched controls to experience acne (6.0% vs 3.6%), hirsutism (8.1% [47/508] vs 5.5% [84/1524]), and infertility (1.7% vs 0.4%); all P&lt;0.01. Pediatric patients were more likely to experience pubertal development issues (10.5% vs 1.8%), acne (8.4% vs 5.1%), and advanced bone age (1.2% vs 0.1%); all P&lt;0.05. Conclusions: Compared to matched controls, both adult and pediatric patients with assumed classic CAH had significantly more disease-related comorbidities and potential GC treatment-related conditions, indicating the challenges with current GC treatments. This study was limited by the assumed nature of classic CAH due to lack of a specific ICD code, but the combination of chronic GC use (&gt;75% days) with the diagnosis code most likely used in these patients (adrenogenital disorder) supports the validity of this analysis.