Identifying High-risk Asthma With Utilization Data: A Revised HEDIS Definition

Objective

: To develop a definition of high-risk asthma that more precisely identifies patients needing case management than the 2006 Healthcare Effectiveness Data and Information Set (HEDIS) definition.

Study Design

: Two-year claims-based study, with cross-sectional phone survey data, for a sample of 769 youths (age 11-17 years) with asthma.

Methods: The 2006 HEDIS measure defines high-risk asthma as meeting any of the following criteria: =1 emergency department (ED) visits, =1 hospitalizations for asthma, =4 asthma medication prescriptions, or =4 ambulatory visits for asthma with =2 prescriptions for asthma medication in 1 year. We created a revised definition =1 ED visits or =1 hospitalizations for asthma or =1 oral steroid prescriptions for asthma) and identified patients with high-risk asthma in year 1 according to each definition. We compared the 2 groups on demographic and clinical characteristics, and healthcare utilization and costs in years 1 and 2.

Results

: The revised definition identified 29% of the sample as having high-risk asthma, whereas the 2006 definition identified 67%. Compared with the 2006 definition, the revised definition identified patients with significantly greater asthma-related physical health problems and higher medical costs in year 1. In year 2, youths classified as high risk by the revised definition made more ED visits and were more likely to use oral steroids than those classified as high risk by the 2006 definition. Conclusion: The revised high-risk asthma definition identifies half as many individuals and is better able to identify patients with poorly controlled asthma in the subsequent year.

(Am J Manag Care. 2008;14(7):450-456)

This study developed and tested a definition of high-risk asthma based on a single year of patient utilization data that, compared with the 2006 HEDIS definition, more precisely identified patients needing case management.

The 2006 HEDIS definition categorized 67% of youths with asthma as high risk, whereas the revised definition categorized just 29% of youths as high risk.

The Figure

Compared with the 2006 HEDIS definition, the revised definition identified youths with significantly greater asthma-related physical health problems and higher medical costs in the first year, and youths who made more emergency department visits and were more likely to use oral steroids in the second year.Asthma is the most common chronic illness of childhood and adolescence. In many individuals, it persists into adulthood, causing functional impairment and resulting in considerable use of health services.^1-4 Randomized controlled trials have shown asthma disease management programs to be effective,^5-8 and some organized healthcare systems have integrated disease management systems into their process of care. The resources directed toward disease management can be optimized by targeting youths with the highest risk of adverse consequences. A method for identifying these youths based solely on administrative data would be valuable for health plans.^9,10 The Healthcare Effectiveness Data and Information Set (HEDIS) definition of high-risk asthma is one method used to identify patients through administrative data. shows the 2006 HEDIS definition and the revised definition proposed in this study. There is evidence to suggest the 2006 HEDIS definition resulted in high levels of misclassification.^11,12 A prior study found the definition to be overly broad because 2 criteria (“4 or more prescriptions for asthma medication” and “4 or more ambulatory visits for asthma plus 2 or more prescriptions for asthma medication”) resulted in including large numbers of young people and may represent patients adhering to and doing well with care.¹²

The HEDIS definition of high-risk asthma was amended in 2007 to reduce the amount of misclassification. The 2007 definition requires patients to meet at least 1 of the utilization criteria in a 12-month period for 2 consecutive 12-month periods and the criteria met in each period do not need to be the same ones. Although the extended time period increases the fidelity of the HEDIS definition, the 24-month period limits the definition’s utility as a case-finding tool. A definition of high-risk asthma that requires only 12 months of utilization data, instead of 24 months, would enable health plans to identify patients needing disease management in a time frame that would be amenable to preventive interventions.

In this article we describe development of a revised definition that identifies patients with asthma who are at risk for adverse outcomes, using 12 months of utilization data. The revised definition we proposed is similar to the 2006 definition in that only 12 months of utilization data are required, but the criteria are different. We removed 2 above-mentioned criteria (“4 or more prescriptions for asthma medication” and “4 or more ambulatory visits for asthma plus 2 or more prescriptions for asthma medication”), hypothesizing that youths who met only these criteria were not as a group at high risk for adverse outcomes. The criterion of 1 or more oral steroid prescriptions for asthma was added to capture youths requiring treatment for significant exacerbations. In this study we tested the revised definition against the 2006 HEDIS definition to determine whether one is more suitable than the other for identifying high-risk patients. Compared with the 2006 HEDIS definition, we hypothesized the revised definition would capture fewer of the youths with well-controlled persistent asthma and fewer of the youths with intermittent asthma.

Study Population

METHODS

• At least 1 emergency department (ED) or urgent care visit in the past year with an asthma diagnosis and at least 1 asthma prescription during that year.

• At least 1 visit in the past year with an asthma diagnosis and another in the past 18 months, and at least 1 asthma prescription.

• At least 4 prescriptions for asthma medication in the past year.

These criteria were developed to identify youths with active asthma and screen out patients with very mild asthma (such as mild exercise-induced asthma) and youths with spurious asthma diagnoses (ie, wheezing secondary to acute respiratory infection). All youths meeting inclusion criteria were invited to participate in the STAR study. Participants in the STAR study with cost and utilization data were included in this analysis. All participants gave informed consent. The study protocols were reviewed and approved by the institutional review board of GHC.

Data Collection

High-risk status according to the 2006 HEDIS and revised definitions was determined based on individual utilization in year 1 according to the criteria shown in the Figure. We examined the number of youths identified by individual criteria in order to compare the relative contributions of each criterion. Descriptive statistics were used to evaluate the revised definition of high-risk asthma, first by comparing the characteristics of high-risk youths with those of low-risk youths identified by each definition, and second by comparing the characteristics of the high-risk youths identified by each definition.

Differences between the high-risk and low-risk groups within each definition were evaluated by t tests for groups with unequal variance and Pearson χ2 tests. Differences between the high-risk groups identified by each definition also were compared by t tests for groups with unequal variance and Pearson χ2 tests. For all tests a P value of less than .05 was considered significant. The characteristics examined were youth and parent demographics, health characteristics including asthma symptom days, and health service costs and utilization in year 1 and year 2. The analysis was conducted using Stata version 8.0.¹⁸

RESULTS

Table 1

The demographic and health characteristics of the total sample are described in . The 2006 HEDIS definition classified 518 youths (67%) as high risk, whereas the revised definition classified only 223 youths (29%) as high risk. All youths classified as high risk by the revised definition also were classified as high risk by the 2006 HEDIS definition.

Criterion and Stepwise Comparison of High-risk Definitions

Table 2

reports the number of youths identified by each individual criterion. The definitions also were examined in a stepwise manner, and the cumulative number of youths identified with each additional criterion are reported for each definition. Nine youths (1.2%) had inpatient hospitalizations, and 65 youths (8.5%) had inpatient hospitalizations or ED visits. The addition of the revised definition criterion “1 or more prescriptions for oral steroids” identified a total of 223 youths (29.0%). In contrast, the addition of the HEDIS criterion “4 or more prescriptions for asthma” identified 514 youths (66.8%), and the fourth HEDIS criterion “4 or more ambulatory visits and 2 or more prescriptions for asthma” captured an additional 4 youths, for a total of 518 (67.4%). The 2006 HEDIS definition identified 295 youths as high risk that the revised definition did not identify; these 295 youths had no asthma-related hospitalizations, ED visits, or prescriptions for oral steroids.

Demographic and Health Characteristics by Risk Group

Table 3

Cost and utilization of health services for each group in years 1 and 2 are presented in and described below. For the total sample (N = 769) total healthcare costs were $2759 in year 1 and $2503 in year 2.

2006 HEDIS Definition of High-risk Versus Low-risk Youths. There was no difference in year 1 total health service costs between the 2006 HEDIS high-risk and low-risk groups; however, year 2 total health service costs were higher for the high-risk group than for the low-risk group. Utilization of all types (inpatient hospitalizations for asthma, ED and ambulatory visits for asthma, and for prescriptions for asthma medication) in both year 1 and year 2 was higher for the 2006 HEDIS definition high-risk group than for the lowrisk group.

Revised Definition of High-risk Versus Low-risk Youths. Total health service costs in both year 1 and year 2 were higher for the revised definition high-risk group compared with the low-risk group. Compared with the low-risk group, the high-risk group had higher utilization of all types in year 1 and higher utilization of all types except inpatient hospitalizations in year 2.

Comparison of High-risk Youths According to the 2 Definitions. The revised definition high-risk group had higher year 1 total health service costs than the 2006 HEDIS high-risk group. Year 2 total health service costs were $600 higher for the revised definition high-risk group compared with the 2006 HEDIS definition high-risk group, but were not statistically different. Compared with the 2006 HEDIS definition high-risk group, youths in the revised definition high-risk group made more ED visits and outpatient visits, and were more likely to have used any oral steroids for asthma in year 1. In year 2, youths in the revised definition high-risk group made more ED visits and were more likely to have used any oral steroids for asthma than the 2006 HEDIS definition high-risk group.

DISCUSSION

The revised definition for high-risk asthma proposed here is an easily applied tool for health plans wanting to identify a subset of youths with asthma who are likely to benefit from care management based on their risk of poor medical and cost outcomes.

AcknowledgmentsThe authors thank Fred Zimmerman, PhD, for comments regarding the analysis and Malia Oliver for assistance with the data. Any errors are those of the authors.

Author Affiliations: From the Department of Health Services (AVB), the Department of Pediatrics (PL, LPR), and the Department of Psychiatry & Behavioral Sciences (EM, WJK), University of Washington, Seattle; the Center for Health Studies, Group Health Cooperative (PL), Seattle; and the Children’s Hospital and Regional Medical Center (LPR, EM), Seattle.

Funding Source: This study was funded by the National Institute of Mental Health (grant RO1 MH067587 01A1) and the Agency for Healthcare Research and Quality (grant 5T32HS013853-03).

Author Disclosure: The authors (AVB, PL, LPR, EM, WJK) report no relationship or financial interest with any entity that would pose a conflict of interest with the subject matter of this article.

Authorship Information: Concept and design (AVB, PL, LPR, WJK); acquisition of data (PL, LPR, WJK); analysis and interpretation of data (AVB, PL, LPR, WJK); drafting of the manuscript (AVB, PL, LPR, EM, WJK); critical revision of the manuscript for important intellectual content (AVB, PL, LPR, EM, WJK); statistical analysis (AVB, PL); provision of study materials or patients (EM); obtaining funding (LPR, WJK); and supervision (PL).

Address correspondence to: Antonia V. Bennett, MA, Department of Health Services, University of Washington, Box 357660, Seattle, WA 98195-7660. E-mail: abenn@u.washington.edu.

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