For most chronic conditions, the burden of hospitalization increases with age. Congenital adrenal hyperplasia appears to follow a very different pattern.
A nationwide Swiss study published in September 2026 found that hospitalizations among people with congenital adrenal hyperplasia, or CAH, were concentrated most heavily at the very beginning of life. Infants and young children experienced disproportionately complex hospital stays, while the pattern in people without CAH moved in the opposite direction, increasing primarily with age.
The reason becomes clearer when you look at what CAH does to the body.
CAH is a group of inherited disorders affecting the adrenal glands and their ability to produce essential hormones, particularly cortisol and, in some forms, aldosterone. In babies with severe salt-wasting CAH, hormone deficiencies can lead to dehydration, dangerously low sodium, low blood pressure and potentially life-threatening adrenal crisis within the first weeks of life.
Treatment has transformed CAH into a manageable lifelong condition, but replacing hormones that the body normally regulates minute by minute is complicated. The new research shows just how heavily that challenge can weigh on patients early in life, while also revealing a different set of health burdens that can accumulate into adulthood.
What Congenital Adrenal Hyperplasia Actually Is
CAH is a group of rare inherited autosomal recessive disorders caused by a deficiency of one of the enzymes needed to make specific hormones. It affects the adrenal glands located at the top of each kidney, which are normally responsible for producing three different hormone classes: corticosteroids, mineralocorticoids, and androgens. An enzyme deficiency prevents the body from producing one or more of these hormones and results in overproduction of another type of hormone precursor to compensate.
CAH due to 21-hydroxylase deficiency is responsible for more than 95% of all cases and is broken down further into classical CAH – which can be subdivided into salt-wasting and simple virilizing forms – and non-classical CAH. The enzyme 21-hydroxylase is needed to convert cholesterol into cortisol and aldosterone. Without it, cortisol levels fall, the pituitary gland pushes harder to compensate, and the adrenal glands produce excess androgens instead. Annual incidence ranges from 1 in 5,000 to 1 in 15,000 births, with prevalence estimated at approximately 1 in 10,000.
Classic CAH is characterized by impaired cortisol and aldosterone synthesis, requiring lifelong glucocorticoid therapy to replace cortisol and, often, to suppress excess ACTH and adrenal androgens.
Two Faces of Classic CAH
Classic CAH comes in two distinct forms, and the difference between them matters enormously in those first weeks of life. In salt-wasting CAH, the adrenal glands make too little aldosterone, causing the body to lose excessive sodium in urine. Without diagnosis, symptoms appear within days or weeks of birth and can be fatal. Salt-wasting CAH accounts for approximately 75% of all classic CAH cases, with the simple virilizing form making up the remaining 25%.
Symptoms of salt-wasting CAH include dehydration, poor feeding, diarrhea, vomiting, heart rhythm problems, low blood pressure, very low blood sodium, low blood glucose, and metabolic acidosis. Shock in infants with salt-wasting is called adrenal crisis, and signs include confusion, irritability, rapid heart rate, and coma.
Non-classical CAH is milder and may or may not present symptoms. The gap in severity between these presentations explains why newborn screening became a public health priority. Newborns in the United States are routinely screened for CAH using a blood spot measurement of 17-hydroxyprogesterone (17-OHP), a hormone precursor that accumulates when 21-hydroxylase is absent.
Treatment That Lasts a Lifetime
Patients with classic CAH require daily medication for their entire lives. If medication is stopped, symptoms return. The backbone of treatment is hydrocortisone, a synthetic form of cortisol. Those with salt-wasting CAH also require fludrocortisone, a mineralocorticoid that helps the kidneys retain sodium and regulate blood pressure.
Two or more daily oral doses of hydrocortisone cannot precisely replicate the physiologic circadian rhythms of the HPA axis, meaning patients are often either under-treated or over-treated. Under-treatment leaves excess androgens in circulation, which can cause premature puberty in children and infertility in adults. Chronic exposure to supraphysiologic glucocorticoid doses can lead to complications including growth suppression, decreased bone density, increased fracture risk, obesity, insulin resistance, hypertension, and diabetes.
How CAH Inverts the Usual Pattern of Hospitalization
The nationwide Swiss study highlighted earlier offers a striking look at how the healthcare burden of CAH changes across a person’s lifetime. Using hospital discharge data from 2011 through 2022, researchers examined more than 12.5 million hospitalizations, including 2,020 involving people with CAH.
The age pattern was almost the reverse of what researchers saw in the general population. Among people without CAH, hospitalization rates increased with age and were highest among older adults. With CAH, however, hospitalization incidence was highest among neonates (newborns under 28 months) and infants, followed by young children between 1 and 4 years old.
The difference wasn’t limited to how often these young patients were hospitalized. Infants with CAH had an average of 5.5 diagnoses recorded during each hospitalization, a level of medical complexity that wasn’t reached in the general population until around age 60. Endocrine and metabolic disorders were the leading causes of hospitalization among people with CAH across all age groups.
Together, the findings help explain the unusual pattern introduced earlier: CAH can place some of its greatest demands on the healthcare system during the earliest years of life, rather than primarily in old age.
The ICU, Ventilators, and Infection Risk
People with CAH tended to have more health problems documented during each hospital stay, spent longer in the hospital and ICU, and were more likely to need help breathing with a ventilator. These differences appeared across age groups but were especially pronounced during the first year of life.
Infants with CAH were nearly three times as likely to require mechanical ventilation as infants without the condition. Needing this kind of breathing support is a sign of serious illness and illustrates how quickly complications can become severe in very young children with CAH.
The study also found that people with CAH were more likely to be hospitalized for infections from childhood through adulthood. Illness presents an additional challenge because the body normally produces more cortisol during physical stress. People with classic CAH cannot produce an adequate cortisol response on their own.
This is why treatment plans often include “stress dosing,” or temporarily increasing glucocorticoid medication during illnesses, fever, surgery or other major physical stress. Families and patients are taught when and how to use these additional doses and when symptoms require urgent medical attention.
Salt-wasting crises can develop quickly in young children with CAH, making it especially important for families to recognize warning signs such as vomiting, dehydration, unusual weakness or lethargy, and difficulty keeping medication down. Families are typically given an emergency plan explaining when stress dosing is needed and when to seek urgent medical care.
The Long Arm of Early-Life Stress
Complication rates in adults with CAH were consistently higher than in pediatric patients, reflecting the cumulative nature of CAH- and glucocorticoid-related morbidity over a lifetime. Maintaining the right cortisol level requires avoiding both the dangers of under-replacement – adrenal crisis and infection vulnerability – and the dangers of over-replacement, including metabolic disease and bone loss.
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What This Means for Families and Clinicians
The highest-risk window for people with congenital adrenal hyperplasia is the first 12 months of life. Neonatal and infant hospitalizations in CAH are not just more frequent but categorically more complex, with higher ICU rates, longer stays, more diagnoses per admission, and a significantly elevated risk of requiring breathing support. Families of children newly diagnosed with CAH need detailed written sick-day protocols – specifying when to give stress doses of hydrocortisone, when to go to the emergency room, and what to tell clinicians who may be unfamiliar with the condition – before they leave the hospital for the first time.
For clinicians and health systems, the data points toward a persistent gap between the complexity of early CAH presentations and the infrastructure typically designed around managing chronic disease in adults. Pediatric endocrinology teams, emergency departments, and primary care providers all interact with these patients, and all require familiarity with adrenal crisis recognition and management. A child with CAH who develops a fever needs prompt assessment and likely a stress dose, not a wait-and-see approach.
CAH requires active, consistent management at every age, with the stakes highest at the very start. The Hafner study’s population-level data makes clear that current infrastructure and protocols must account for this early-life concentration of risk – and that long-term follow-up studies are needed to measure whether improved early management reduces the cumulative burden carried into adulthood.
Disclaimer: The author is not a licensed medical professional. The information provided is for general informational and educational purposes only and is based on research from publicly available, reputable sources. It is not intended to constitute, and should not be relied upon as, medical advice, diagnosis, or treatment. Always consult a licensed physician or other qualified healthcare provider regarding any medical condition, symptoms, or medications. Do not disregard, avoid, or delay seeking professional medical advice or treatment because of information contained herein.
AI Disclaimer: This article was created with the assistance of AI tools and reviewed by a human editor.
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