The study uses the Commercial Claims and Encounters database portion of the MarketScan Databases for the years 2003–2010. The Commercial Claims and Encounters data track insurance claims from providers using a nationwide sample of employees and dependents covered by large self-insured employers and regional health plans. The dataset expands dramatically over the years and contains a large proportion of the US commercially insured population, ranging from ~8 million individuals in 2003 (~2.6% of the US population) to 45 million in 2010 (~14.7% of the US population).

Our analyses included adolescents aged 11–21 years during at least 1 of the study years. We focused on those who were continuously enrolled in health insurance plans during each calendar year. Adolescents were divided into 3 age groups based on the Bright Futures guidelines, early adolescence (11–14 years old), middle adolescence (15–17 years old), and late adolescence (18–21 years old), to explore age differences in preventive care visits.

This study was reviewed by the Human Subjects Coordinator at the Centers for Disease Control and Prevention. As an analysis of secondary data without identifiers, this study did not require institutional review board review.

Based on the Healthcare Effectiveness Data and Information Set (HEDIS),¹⁵ we used the International Classification of Diseases-9th Revision codes associated with routine medical examinations to define preventive care visits (ie, V20.2, V70.0, V70.3, V70.5, V70.6, V70.8, and V70.9). Outpatient records with the Current Procedural Terminology codes between 99381 and 99397 (ie, comprehensive preventive care) were also defined as preventive care visits. Our data indicated that comprehensive preventive care was provided in over 80% of the preventive care visits. Outpatient visits with International Classification of Diseases-9th Revision codes or Current Procedural Terminology codes associated with vaccine administration were classified as vaccination-related visits. Note that preventive care and vaccination-related visits are not mutually exclusive.

We considered 7 types of health care providers/agencies: pediatricians, family physicians, internists, obstetricians and gynecologists, specialists/subspecialists, non-physician professionals, and health care facilities or agencies.

Preventive care visit rate was measured by calculating an annual proportion of adolescents who had at least 1 preventive care visit. We compared these annual proportions particularly among 3 time periods: 2003–2004 (pre-recommendation), 2005–2007 (transition), and 2008–2010 (post-recommendation). The same approach was used to study the pattern of vaccination-related visits. Rates of preventive care and vaccination-related visits were also examined by subgroups. To assess changes in visit patterns by individual enrollees, we follow the 1992 birth cohort for 8 consecutive years.

Including preventive care provided by specialists/subspecialists may be subject to coding errors. Thus, a sensitivity analysis was performed by excluding preventive visits to specialists/subspecialists (ie, coded as outpatient visits, not preventive visits).

A total of 4 732 297 adolescents were included, representing 11 933 132 outpatient visits during the 8 years. The size of the study population increased from 924 381 to 1 983 226 during 2003–2010 (Table I). In each year, about 51% were males and 49% were females, and approximately 37%, 30%, and 33% were in their early, middle, and late adolescence, respectively. Most of our study population resided in the south and north central regions (61%) and in metropolitan statistical areas (MSAs) (over 80%). Preferred provider organization was the most prevalent health plan among adolescents.

Yearly improvements in preventive care visits for adolescents were substantial between 2003 and 2010. The rates, however, were far from optimal in relation to the recommendations by Bright Futures. Several studies have documented barriers to access and to provision of preventive care services, including low income, not having continuous insurance coverage, lack of confidentiality, limitations on choices of providers, physician attitudes and beliefs, and lack of provider training.^4,16–21 Although expansions in Medicaid and State Children’s Health Insurance Programhave improved adolescents’ access to health care services,²² and several intervention strategies have been proven to be effective in addressing these barriers,^23–25 our result suggests that ongoing efforts are needed to further promote the use and delivery of preventive care.

Our findings revealed that preventive visit rate was considerably lower among middle and late adolescents. Although the goals of vaccination are to vaccinate as early as possible, adolescents would be best served if they had preventive visits when they were initiating risky behaviors (middle adolescence). Thus, efforts to increase preventive visits among all ages during adolescence are important.

Several findings suggested that ACIP recommendations were associated with the increase in adolescents’ vaccination-related visits. First, the average growth rate of vaccination-related visits was higher during the years in which ACIP issued recommendations. Second, most vaccines recommended were targeted at early adolescents, which was consistent with the finding that visit rate was higher among early adolescents. Finally, HPV was recommended in 2007. As a result, females in all age groups were more likely to make a vaccination-related visit after 2006. Our data showed a decrease in vaccination-related visits among middle and late adolescent females during 2009–2010. This may result from a cohort effect because older females may have received all recommended vaccines at an earlier age, thereby reducing their need for vaccination-related visits.

Similar trends in preventive and vaccination-related visits are consistent with the notion that immunization could act as a hook to increase healthcare visits, which may provide an opportunity for the delivery of other types of preventive care services.²⁶

Our longitudinal analyses indicated that only 2.4% of adolescents made an annual preventive care visit and 16.1% had not made any preventive visit during the same time period. These results reinforce our earlier conclusion that significant efforts have to be made to increase the use of preventive services among adolescents.

Our findings should be interpreted in light of some limitations. First, our data show that preventive care visits increased rapidly during the years that ACIP issued recommendations. The causal relationship, however, is not statistically tested and other factors may play a vital role in the improvement in preventive visits. For example, the fact that the proportion of adolescents making at least 1 preventive care visit is a HE-DIS measure²⁷ and the publication of several clinical guidelines^1,3,28 may have led to increases in preventive care visits. Moreover, changes in insurance coverage, in reimbursements for preventive care and immunization services, or in regional or school requirements for immunization and regular preventive care visits may also play a role. However, preventive care visits for adolescents have been adopted as a HEDIS measure since 1996²⁹ and the clinical guidelines were published before our study years. Moreover, we are not aware of any significant change in insurance coverage, reimbursement policy, or in regional or school requirements during transition years. Therefore, these factors are not likely to play a major role in explaining the rapid increase in preventive care visits by adolescents during the transition years.

Other limitations come from the MarketScan data. First, the data were generated from insurance claims and thus included in-plan outpatient visits. We may therefore underestimate preventive care or vaccination-related visits because of the inability to track non-recorded health care visits by adolescents. On the other hand, our definition of preventive care visits includes both routine medical examinations and comprehensive preventive services, which might overestimate the rate of preventive care visits. However, over 80% of the preventive visit records in our data indicated that comprehensive preventive care was provided and these services were coded by physicians. Therefore, we believe that our number represents an acceptably accurate proportion of commercially insured adolescents making an annual preventive visit. Second, the number of our study population increased dramatically during our study period, which, to some extent, may contribute to changes in the rates of preventive and vaccination-related visit. However, the results from the longitudinal analysis confirmed the increasing time trend in preventive visits and also suggested that preventive care is underutilized by adolescents. Third, our study population included adolescents continuously enrolled in a private insurance plan, which limited generalizability to the US population. The low preventive care visit rate among commercially insured adolescents, however, raises serious concerns as this group is likely to represent a better scenario compared with the uninsured population.

Our study adds to the current literature by presenting time trends in preventive care visits by commercially insured adolescents over an 8-year period. Although ACIP recommendations and a variety of policies and efforts might have been associated with the substantial improvement in adolescents seeking preventive care, the results indicate that innovative interventions are necessary to promote further increases in the uptake of preventive services by adolescents.