Ambulatory care among young adults in the United States.

Context Little is known about how young adults 20 to 29 years of age use ambulatory medical care. Contribution The authors found that young adults have fewer ambulatory care visits than adolescents or adults 30 to 39 years of age. In addition, young adults who are male, black, or Hispanic have fewer visits than other young adults. Implication Young adults underutilize ambulatory care relative to other age groups. The Editors Young adults face many of the same health care challenges as adolescents, yet fewer resources are available to care for this patient population (1). Although the mortality rate among young adults is more than twice that among adolescents, young adults remain the most likely age group to be uninsured (2, 3). Approximately one third of young adults are uninsured, which hinders access to care and results in delayed treatment and difficulty filling prescription medications (2, 3). The prevalence of homicide, motor vehicle accidents, substance abuse, and sexually transmitted diseases (STDs) all peak in young adulthood (1, 4, 5). Compared with adolescents, young adults have 3 times the suicide rate; nearly 3 times the incidence of HIV; and higher rates of smoking (41.8% vs. 12.4), binge drinking (41.8% vs. 9.7%), and illicit drug use (19.7% vs. 9.5%) (1, 5). Similarly, young adults have considerably higher rates of STDs, illicit drug use, alcohol use, and tobacco use than older adults (4, 5). Finally, young adults have the highest rate of serious psychological distress among all adults (17.9%), yet fewer than half (46.9%) of those with a major depressive episode receive treatment (5, 6). Healthy People 2010 established several national objectives, including reducing mortality, alcohol- and drug- related injuries, motor vehicle accidents, and the incidence of STDs among young adults (7, 8), yet where young adults are receiving care and what preventive services are being provided to help reach these goals are unclear. Although several studies have described health care in adolescents (911), little is known about ambulatory care of young adults. A comprehensive understanding of where young adults access care and what preventive services are provided are needed to guide future initiatives toward improving health care for young adults and achieving the national objectives. We used data from the National Ambulatory Medical Care Survey (NAMCS) and National Hospital Ambulatory Medical Care Survey (NHAMCS) between 1996 and 2006 to characterize ambulatory medical care among young adults age 20 to 29 years. We sought to compare health care utilization among young adults with that among adolescents and older adults, to describe ambulatory medical care of young adults (types of visits, reasons for visits, and sites of care), and to examine the provision of preventive care to young adults. On the basis of studies in adolescents (11, 12), we hypothesized that young adults utilize health care less than other age groups and infrequently receive age-appropriate preventive care directed at the most common threats to their health. Methods This study was approved by the University of Rochester Research Subjects Review Board under exempt status (RSRB00026060). Design of the NAMCS and NHAMCS The NAMCS is a national cross-sectional survey of patient visits to nonfederal, office-based physicians in the United States. Similarly, NHAMCS is a cross-sectional survey of patient visits to outpatient departments of general and short-stay hospitals. The surveys both utilize a multistage probability design to select a stratified systematic sample of patient visits and use visit weights to extrapolate these encounters to estimates of national utilization of ambulatory medical services (13). The NAMCS uses a 3-stage sampling design based on geographic area, physician practices within the area, and patient visits within the practice (13). The NHAMCS uses a 4-stage probability design based on geographically defined areas, hospitals within these areas, clinics within the outpatient departments, and patient visits to these clinics (14). A comprehensive explanation of the methods used for data collection, sampling, and weighting in NAMCS and NHAMCS are available online at www.cdc.gov/nchs/about/major/ahcd/ahcd1.htm. The protocols used by NAMCS were approved by the National Center for Health Statistics Institutional Review Board (15). Creation of Variables We defined young adults as people between 20 and 29 years of age. We chose this age range because it represents a period when many people lose their insurance coverage, it conforms to census data, and it is commonly used by insurers to determine the number of reimbursable visits for preventive care (16). To ensure that our findings were not dependent on the definition of young adult, we also ran our key analyses after redefining young adults as people 18 to 24 years of age. To focus our analyses and allow for sex comparisons, we excluded all visits related to pregnancy. We estimated utilization rates by using visit data from NAMCS and NHAMCS and population data from the U.S. Census (17, 18) between 2000 and 2006 to calculate the number of annual visits per capita for adolescents, young adults, and older adults, stratified by sex, race, and ethnicity. We used the American Community Survey March Supplements between 2001 and 2007 (in which data are reported for the previous year, that is, 2000 to 2006) to obtain the proportion of young adults without insurance during this period (dataferrett.census.gov). We used data from NAMCS and NHAMCS between 1996 and 2006 to characterize types of visits from young adults (acute, chronic, or preventive), the locations where young adults receive care, the specialties of providers seen, and the counseling rendered to young adults during office visits. The NAMCS and NHAMCS recorded the major reason for the patient visit as acute problem; chronic problem, routine; chronic problem, flare-up; pre/post-surgery; and preventive care. We combined the 2 chronic problem visits in our analysis because both represent similar types of visits for management of chronic disease. We used the reason for visits classification codes to tabulate the principal reason for the ambulatory encounter. If the principal reason for the visit was listed as a follow-up visit or an administrative visit or could not be coded, we used the secondary reason for the visit. We defined primary care physicians to include physicians practicing in internal medicine, pediatrics, family practice, general practice, general preventive medicine, or public health and general preventive medicine. We defined public insurance as Medicaid or Medicare and uninsured visits as those with payment listed as no charge, charity care, or self-pay. Statistical Analysis We performed all statistical tests and variance estimates by using SAS, version 9.1 (SAS Institute, Cary, North Carolina), and SAS-callable SUDAAN (Research Triangle Institute, Research Triangle Park, North Carolina) functions to appropriately weight visits and account for the complex sampling design (19). All proportions were compared by using an adjusted Wald F test that accounted for the complex sampling design. We did not include data with missing type of visit (2.6%), missing payment type (1.4%), missing reason for visit (6.3%), uncodeable reason for visit (<0.1%), or visit for administrative reason (<0.1%) in analyses involving these variables. The National Center for Health Statistics considers estimates reliable if the relative SE is less than 30% of the point estimate and considers estimates derived from fewer than 30 total visits unreliable regardless of the relative SE (13). All values reported are based on 30 or more visits, unless otherwise noted. All tests are 2-tailed, and a P value less than 0.05 was considered statistically significant. Role of the Funding Source This study was not supported by extramural funding. Results Between 1996 and 2006, 14599 physicians (67.3% of eligible physicians) participated in NAMCS. During the same period, 4363 hospitals participated in NHAMCS, representing a 94.0% overall participation rate. A total of 52709 unweighted visits were recorded by young adults between 1996 and 2006. Table 1 reports weighted characteristics of the data. Table 1. Ambulatory Care Visits by Young Adults Age 20 to 29 Years Between 1996 and 2006, by Patient Characteristic Utilization of Ambulatory Care Figure 1 shows utilization rates among different age groups of white, black, and Hispanic males and females. For males, utilization rates were highest among children and older men, and the lowest utilization rates were seen among young men. Young men had lower rates of annual utilization of ambulatory medical care per capita (1.10 [95% CI, 1.06 to 1.15] annual visits per capita) than male adolescents age 15 to 19 years (1.65 [CI, 1.60 to 1.70]) or older men age 30 to 39 years (1.73 [CI, 1.67 to 1.79]) (Appendix Table). Young men had less than half the rate of per-capita utilization than young women (1.10 [CI, 1.06 to 1.15] vs. 2.31 [CI, 2.26 to 2.35]) (Appendix Table). For both males and females, black and Hispanic individuals had lower utilization than white individuals. Figure 1. Per-capita annual ambulatory care utilization between 2000 and 2006, by age group. Appendix Table. Per-Capita Annual Ambulatory Health Care Visits by Adolescents and Adults, 2000 to 2006 Table 2 shows utilization rates for young adults with and without health insurance. Young adults with insurance had more than triple the rate of health care utilization than those without insurance. In addition, among insured and uninsured young adults, men had lower rates of utilization than women and black men had lower rates of utilization than white men. Table 2. Per-Capita Annual Ambulatory Care Visits by Young Adults Age 20 to 29 Years Between 2000 and 2006, by Insurance Status Types of Visits Figure 2 shows visits per capita for acute problems, chronic problem