What Is Between Pediatric and Geriatric Care?

There is no single medical specialty that mirrors pediatrics or geriatrics for the decades in between. The vast stretch of adulthood, roughly from the late teens through the early sixties, is covered by a patchwork of disciplines: adolescent medicine, internal medicine, family medicine, obstetrics, and dozens of organ-specific specialties. The gap is not just a naming curiosity. It has real consequences for how people experience healthcare during the longest phase of their lives, particularly at the transitions into and out of the age ranges where dedicated specialties exist.

Adolescent and Young Adult Medicine

The closest thing to a named bridge between pediatrics and adult care is adolescent and young adult medicine, a subspecialty that specifically addresses the health needs of people from roughly age 10 through the mid-twenties. Research in neuroscience showing that brain development continues into the third decade of life, combined with evidence that risk behaviors associated with adolescence persist and sometimes increase into the twenties, has driven the field to treat these age groups as a connected medical population rather than splitting them at an arbitrary birthday.¹ The subspecialty covers pubertal development, sexual health, gender identity, gynecology, and mental and behavioral health, among other concerns.²

Even so, adolescent medicine remains a relatively small field. Most teenagers and young adults do not see an adolescent medicine specialist. They see a general pediatrician until some cutoff age, then are expected to find an internist or family physician. That handoff is where problems begin.

The Transition From Pediatric to Adult Care

For young people with chronic conditions, the move from a pediatric provider to an adult one is often called “transition care,” and the research paints a mixed picture of how well it works. A systematic review of observational studies found that among young people with life-limiting conditions who transferred to adult services, outpatient attendance went up in some studies and down in others, emergency department visits increased in three out of five studies, and inpatient bed days rose in three out of four studies examined.³ The pattern suggests that, on average, emergency and acute care use tends to increase after the switch, which is the opposite of what a smooth transition should produce.

Congenital heart disease offers one of the clearest examples. Lifelong follow-up is medically necessary, yet one study of over 1,500 patients found that only about 12% successfully transferred to the affiliated adult hospital, and among those who did, the average gap between the last pediatric visit and the first adult visit was nearly three years.⁴ Distance to the referral center was a major factor in delayed transfers. An American Heart Association scientific statement has emphasized that developing self-management skills and gaining independence in healthcare decision-making are critical to making this process work.⁵ The challenge is that these skills need to be built before the transfer happens, and pediatric settings do not always prioritize them.

The difficulties are not unique to heart disease. Patients with congenital conditions of all kinds face obstacles around independence from parents and establishing self-management habits.⁶ The adult healthcare system is structured around patients who arrive already knowing how to schedule appointments, manage prescriptions, and communicate their medical history. Young people coming out of pediatric care, where a parent handled all of that, often do not have those skills yet.

Mental Health During Transition

The transition problem is especially sharp in mental health. People with intellectual and developmental disabilities have psychiatric condition rates as high as roughly a third, and the risk of mental health disorders actually increases during the transition to adulthood.⁷ Moving from pediatric to adult mental health services can cause discontinuity of care precisely when the need for care is intensifying. Researchers have found that the transition of mental health care appears to be at least as problematic as transitions in physical health settings, and possibly worse.

Part of the reason is structural. Pediatric mental health services tend to be more holistic, involving family members and coordinating across school and social services. Adult mental health care is more fragmented, expects the patient to self-advocate, and often has longer wait times. A young person with autism or an intellectual disability who loses their pediatric psychiatrist at age 18 or 21 may struggle for months or longer to find an adult provider willing to take them on.

Why Young Adults Fall Through the Cracks

Even healthy young adults without chronic conditions tend to disengage from healthcare in their twenties. Before the Affordable Care Act’s coverage expansion, young adults had the lowest rate of any healthcare use at about 72%, compared with 88% for children and 83% for adolescents.⁸ Some of that gap is simply the invincibility of youth: healthy 22-year-olds tend not to think they need a doctor. But a significant portion is practical. Aging out of a parent’s insurance, not having an established primary care provider, and not knowing how to navigate the adult healthcare system all contribute.

Insurance plays a major role. Research on adolescents and young adults transitioning to adult care has found that regardless of whether they had public or private insurance, insurance was a key factor in deciding where they could receive care, and many described financial difficulties affording it.⁹ The ACA’s dependent coverage provision, which lets young adults stay on a parent’s plan until age 26, has helped. Studies found it was associated with a reduction in insurance gaps of about 2.4 percentage points for young adults with special healthcare needs.¹⁰ Young adults with disabilities also saw gains in coverage and reductions in delayed care after the dependent coverage provision and Medicaid expansion took effect.¹¹

Still, turning 26 creates a second cliff. Young adults who gained coverage through a parent’s plan must then find their own, and the same transition difficulties that marked the move from pediatric to adult care can recur in a different form. The healthcare system does not have a built-in mechanism to ensure continuity at this stage either.

Preventive Care Guidelines That Exist but Are Hard to Find

One underappreciated issue is that preventive care recommendations for young adults actually exist, they are just scattered across dozens of specialty-specific guideline documents. When researchers carved out recommendations for ages 18 to 26 from the various professional guidelines, they found a broad set of evidence-backed recommendations, many with high-quality evidence grades.¹² The problem is not a lack of guidance but a lack of consolidation and visibility. A 23-year-old visiting a new internist for the first time is unlikely to receive the full spectrum of age-appropriate preventive screenings unless that provider has actively assembled the relevant recommendations from multiple specialty groups.

This contrasts sharply with pediatrics, where well-child visit schedules are highly standardized and familiar to every provider, and with geriatrics, where screening and management protocols for older adults are similarly well organized. The young-adult years have the evidence but not the infrastructure to deliver it consistently.

The Med-Peds Provider

One physician training model was designed to bridge the pediatric-adult divide directly. Combined internal medicine-pediatrics residency programs train doctors to care for patients from birth through old age. The objectives of these programs include preparing generalists for the full spectrum of illness in newborns, children, adolescents, and adults, and equipping graduates for research in areas shared by the two fields, including adolescent medicine and medical genetics.¹³

In practice, most graduates do continue seeing both adults and children. One survey found that about 82% of med-peds graduates were caring for both age groups, with about a fifth going into subspecialty training and another fifth practicing in rural or underserved areas.¹⁴ An earlier study of over 700 graduates found that 68% were working as generalists, and 85% of those generalists were practicing combined internal medicine-pediatrics rather than choosing one side.¹⁵

Med-peds physicians are particularly well-suited for transition care because they understand both systems. A patient with a childhood-onset condition can, in theory, stay with the same med-peds provider into adulthood without any handoff at all. The limitation is supply. Med-peds makes up a small fraction of all residency graduates, and their practices tend to cluster in academic centers and underserved communities rather than being distributed widely across the healthcare system.

Midlife and the Rise of Chronic Conditions

Once you move past the young adult years, the medical landscape shifts. The thirties, forties, and fifties are when chronic diseases begin accumulating, and the rate of accumulation is steep. In the United States in 2023, about 78% of midlife adults (roughly ages 35 to 64) had at least one of twelve tracked chronic conditions, and over half had multiple chronic conditions simultaneously.¹⁶ For young adults, about 60% had at least one condition, which itself represented an increase from 53% a decade earlier. By older adulthood, the figure was 93%.

Research from India has pointed to a similar phenomenon: chronic diseases including hypertension, diabetes, lung disease, heart disease, arthritis, neurological disease, and cancer were developing earlier than expected, especially in people aged 45 to 54.¹⁷ Early onset of chronic conditions during the working-age years creates a ripple effect: the healthcare burden grows heavier as those individuals age with their conditions rather than developing them later.

The significance for the “what’s between pediatric and geriatric care” question is that midlife adults are often managing increasingly complex health profiles using a system that does not have a dedicated coordinating specialty for them. Geriatrics brings a holistic, multi-condition management philosophy to older adults. Pediatrics does the same for children. For a 50-year-old with diabetes, early kidney disease, depression, and chronic back pain, coordination usually falls to a primary care physician who may have fifteen minutes per visit and a panel of two thousand patients.

Polypharmacy Before Old Age

One concrete consequence of rising chronic disease in midlife is polypharmacy, the use of five or more medications simultaneously. This is commonly thought of as a geriatric problem, but it starts much earlier. A cross-sectional study of over 14,000 patients found that 66% of the total cohort had polypharmacy, and while older patients were overrepresented, middle-aged adults made up a substantial share. Internal medicine units had the highest proportion of polymedicated patients, and the strongest predictors of polypharmacy were the number of existing conditions and the presence of musculoskeletal or metabolic disease.¹⁸

Geriatricians are specifically trained to review medication lists, deprescribe unnecessary drugs, and watch for harmful interactions. But the typical 55-year-old on six medications does not see a geriatrician. They see an internist or family physician who may or may not have the time to perform the same kind of comprehensive medication review. The skills exist within the medical system; they just are not deployed for middle-aged adults the way they are for those over 65.

Body Composition and Metabolic Shifts at Midlife

Midlife also brings physiological changes that do not fit neatly into any single specialty’s wheelhouse. Body composition shifts substantially during the middle decades, with increases in fat mass and decreases in skeletal muscle that set the stage for metabolic disease. A longitudinal study following women over six years found that both chronological aging and ovarian aging contributed to these changes, with consequences for whether the body’s metabolic environment remains healthy.¹⁹ Sarcopenia, the loss of muscle mass and strength, has been linked to downstream risks like new-onset chronic kidney disease in middle-aged and older adults.²⁰

For women, perimenopause and menopause bring a cluster of symptoms and health changes that may affect sleep, mood, cardiovascular risk, and bone density. European clinical practice guidelines recommend that women in peri- and post-menopause who are candidates for hormone therapy can be managed in primary care according to recognized guidelines.²¹ Experts have emphasized a holistic approach: treating multiple symptoms with a single medication when possible, rather than stacking treatments.²² Yet many women report that their primary care providers are not comfortable managing menopause, leaving them to seek out specialists on their own.

Preconception Health and the Forgotten Window

Reproductive health for younger adults presents its own gap. Preconception care, the medical and behavioral interventions that optimize health before pregnancy, influences outcomes for both parents and children. Yet existing research has overwhelmingly focused on women who are already pregnant or postpartum. The prepregnancy phase during adolescence and early adulthood has received very limited attention despite being the period when exposures relevant to later pregnancy outcomes actually occur.²³ This is another example of a period of life that falls between the well-studied endpoints: childhood health is closely monitored, and pregnancy care is intensive, but the years of early adulthood before a first pregnancy often lack a structured healthcare framework.

Brain Health Risks That Start in Midlife

Dementia prevention is typically framed as a concern for older adults, but research increasingly shows that the modifiable risk factors accumulate during middle age. A study of middle-aged and older adults in primary care found that the most prevalent risk factors for dementia were physical inactivity (about 60%), depressive symptoms (roughly 57%), and hypertension (also about 57%).²⁴ Physical inactivity and untreated depression at age 45 are not geriatric problems. They are midlife problems with geriatric consequences. The healthcare system’s tendency to think of dementia prevention as something that belongs to geriatrics means that interventions during the window when they might do the most good, the forties and fifties, often do not happen in a coordinated way.

The Sandwich Generation’s Health

Middle-aged adults face a unique social determinant of health that neither pediatric nor geriatric patients share: many of them are simultaneously caring for their own children and their aging parents. This “sandwich generation” faces difficulties with time management, physical exhaustion, and mental health problems including stress and caregiver burnout.²⁵ Some are also juggling paid employment alongside both caregiving roles, making them what researchers call triple-duty caregivers. Their own health needs tend to get pushed to the bottom of the priority list, and no area of medical practice is specifically oriented toward recognizing or addressing the health impact of this dual caregiving burden.

The irony is worth noting. Pediatrics exists because children’s bodies and developmental needs differ from adults’. Geriatrics exists because aging introduces distinct physiological and cognitive challenges. Midlife adults have their own biology, their own characteristic disease patterns, and their own social stressors. What they do not have is a specialty designed to pull all of it together under one framework. Family medicine and internal medicine come closest, but they cover such a wide scope that the specific concerns of middle age do not get the same focused attention that childhood and old age receive.