The Burden of Illness of Congenital Adrenal Hyperplasia (CAH) in Adults: Results: of a Structured Literature Review

Objectives: Congenital adrenal hyperplasia (CAH) is a group of rare autosomal-recessive disorders that arise from genetic deficiencies in key enzymes involved in cortisol synthesis. The burden of CAH has never been comprehensively reviewed; this literature review was conducted to summarise the existing burden of illness evidence available for these patients. Methods: A structured, comprehensive literature review was conducted to identify articles describing the burden and treatment landscape of CAH. Literature databases (MEDLINE, Embase, the Cochrane Library and EconLit), websites and conference proceedings were searched. Searches were performed in 2016 and updated in June 2020; eligible articles presented evidence for patients with CAH or paediatric patients with adrenal insufficiency (AI), for ≥1 topic of interest (epidemiology; natural history; clinical characteristics; humanistic, caregiver and economic burden; treatment options; or clinical guidelines). The evidence presented here focusses on the humanistic and economic burden of CAH in adults. Results: A total of 3,711 citations were identified and 336 were included; 84 references reported humanistic or economic burden data relevant to adult patients with CAH. 51 publications were identified reporting patient symptoms, comorbidities and cardiometabolic risk factors; 38 reporting on the impact of CAH on health-related quality of life (HRQL); 5 reporting patient views and 2 reporting economic burden associated with CAH. Compared to the general population, adult patients with CAH were found to be significantly shorter, have poorer bone health, increased levels of obesity, impaired male and female fertility, higher blood pressure and cholesterol levels, have more psychiatric and neurological disorders and have poorer cognitive performance. Adult patients with CAH were also found to have greater insulin resistance and higher levels of type 2 diabetes (T2D). CAH patients are also at risk of adrenal crisis, which contributes to excess mortality. The reported HRQL in adults with CAH varies, with increased impairment observed in more severe forms of CAH, and challenges due to living with a chronic disease impacting HRQL varying according to sex. “Sick day rules” where patients need to double or triple treatment doses, have a significant impact on patients’ HRQL and also have an impact on patients’ resource use, with a UK study reporting that CAH patients will implement these rules 171 times over their lifetime, and be hospitalised for adrenal crises on 11 occasions. CAH was also found to have a significant economic impact, with significantly higher annual healthcare costs compared to matched controls (p=0.007 for patients aged 18–40 years; p<0.001 for patients aged ≥40 years). Conclusions: This comprehensive review highlights that CAH in adults is associated with a significant humanistic and economic burden.