Patterns of chronic illness in childhood are both complex and dynamic. Compared to chronic disease in adults, serious chronic illness in children is less common and widely heterogeneous. This has profound implications for the organization of children’s health services, as pediatricians have the difficult task of identifying and caring for children with unusual and varied conditions. Accordingly, child health services have become far more reliant on standardized screening programs and formal systems of referral to regional specialty care programs than are health care systems for adults. Pediatrics has been characterized by rapid progress in preventing serious acute illnesses and in extending the lives of children who previously would have succumbed to their illness early in life. These factors have made the epidemiology of childhood far more dynamic than that of the adult world.
National survey data suggest that 30% of all children have some form of chronic health condition (Table 39-1). If allergies, eczema, minor visual impairments, and other conditions not likely to generate serious consequences are excluded, then between 15% and 20% of all children have a chronic physical, learning, or developmental disorder. Boys have higher rates of chronic illness than do girls. There is considerable variation in the nature and severity of chronic illnesses in children (Table 39-2). The most common serious chronic condition is asthma, with 12% of children having received a diagnosis of asthma at some time in their lives; half of these children were reported to have experienced asthma symptoms in the prior 12 mo (Chapter 138). Mental health and behavioral conditions represent a large and growing number of children with chronic illness. It has been estimated that almost 21% of U.S. children between 9 and 17 yr of age have a diagnosable mental or addictive disorder associated with some impairment; approximately 11% had significant impairment. Estimates suggest that 5% had major depression (Chapter 23) and approximately 6% have attention-deficit/hyperactivity disorder (ADHD) (Chapter 30). Overweight is not usually defined as a chronic health condition; however, in 2008 12% of 2-5 yr olds, 17% of 6-11 yr olds, and nearly 18% of all children aged 12 through 19 yr have a body mass index above the 95th percentile (Chapter 44). Co-morbid conditions such as hypertension and a variety of metabolic disorders may exist.
The severity and impact of chronic illnesses can vary significantly. Approximately 9% of all children have activity limitations due to one or more chronic illnesses, which has been relatively stable since 2001. Of these children, 40% have developmental or learning disorders, 35% have chronic physical conditions, and 25% report chronic mental health disorders. Approximately 2% of children have chronic conditions and activity limitation severe enough to meet eligibility criteria for the Supplemental Security Income program. Between 12% and 18% of all children meet the chronic illness and elevated service needs of the children with special health care needs (CSHCN) definition, depending on the data set that is examined.
These current prevalence figures represent a substantial increase in childhood chronic illness in the past several decades. While approximately 9% of children were reported to have a chronic health condition that limited their activities in 2005, the comparable figure in 1960 was only 2%. Although the increase in childhood chronic illness is likely due in part to changes in survey methodologies, improvements in diagnosis, and expanded public awareness of behavioral and developmental disorders, there is strong evidence that the prevalence of certain important chronic child health conditions has increased. Asthma rates rose from <4% in 1980 to 9% in 2007, with the highest rates among the poorest children. The prevalence of ADHD (Chapter 30) and autism (Chapter 28) has also increased considerably. Although improvements in the survival of infants and young children from prematurity, congenital anomalies, and genetic disorders have also contributed to the rising prevalence rates, this source accounts for only a small portion of all chronic illness in childhood.
Chronic illness accounts for a growing portion of child health care expenditures, serious illness, hospitalizations, and deaths among children in the USA. Children with a chronic illness are hospitalized approximately 4 times more often and spend more than 7 times as many days in the hospital as children without a chronic illness. Estimates suggest that chronic illness accounts for the majority of all nontraumatic hospitalizations for children, a figure that has more than doubled in the past 4 decades, and children with chronic illnesses are experiencing increasing lengths of stay. Multiple admissions in any given year have also risen substantially. The majority of all non–trauma related deaths in children are now due to chronic disorders. This historical shift in the distribution of pediatric hospitalization and mortality reflects not only the rise in the prevalence of childhood chronic illness, but also marked reductions in the incidence of serious acute pediatric illness.
Chronic illness is also contributing more profoundly to social disparities in child health. There are somewhat conflicting data on the association of poverty and the prevalence of chronic disorders in children, although most studies suggest a moderate elevation among poor children. Children enrolled in welfare cash assistance programs are more likely to have a chronic illness, and poor and African-American children have greater limitations in activity due to chronic conditions. Latino school-aged children have rates of chronic illness that are similar to non-Latino whites; however, there remains little information on the prevalence and impact of chronic illness and its functional impact among the different subgroups of Latino children as well as subgroups of Asian and Pacific Islanders.
