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Wednesday, October 24, 2007
P4-11

ADVERSE SELECTION OF A CONSUMER-DIRECTED HEALTH PLAN IN A LARGE EMPLOYER DIABETES POPULATION

Michael B. Nichol, PhD1, Joanne Wu, MS1, Tara K. Knight, PhD1, Thomas Parry, PhD2, and Dennis H. Honda3. (1) University of Southern California, Los Angeles, CA, (2) Integrated Benefits Institute, San Francisco, CA, (3) Pfizer Global Pharmaceutical Operations, Martinez, CA

Purpose: Previous studies have indicated that consumer-directed health plans (CDHP) may appeal disproportionately to the wealthy and healthy. This study investigates the demographic and clinical characteristics, and previous health care utilization and cost, on CDHP selection decisions in a large employer's population with diabetes. Methods: We retrospectively examined medical and pharmaceutical claims, enrollment, and employment data from April 2002 through March 2006 for employees and their dependents. Members who were 18 years or older were included in the analyses if they had at least one diagnosis (ICD-9 code 250.xx) or prescription for diabetes, and at least twelve months of claims data prior to enrollment in a CDHP or non-CDHP. The Charlson Comorbidity score (CCS) was defined using ICD-9 diagnosis codes. Logistic regression was used to assess the factors (demographic, clinical characteristics, and previous health care utilization and cost) associated with the plan selection. Results: 12,325 members were included in the analysis. 630 (6%) were identified as selecting the CDHP, while 9,695 (94%) had never selected the CDHP. The population mean age (SD) was 55.4±16.0 years, and 54% were female. CDHP members were younger (47.5 vs. 55.9 years, p<0.0001), had a shorter length of employment (i.e., proportion less than 5 years, 24% vs. 16%, p<0.0001), were more likely to live in the western region of the United States (62% vs. 53%, p<0.0001), and had lower CCS (0.18±0.47 vs. 0.36±0.69, p<0.0001). The CDHP cohort had fewer hospitalizations (0.10 vs. 0.18, p<0.0001), shorter mean length of stay (0.25 vs. 0.58 days, p<0.0001), and took fewer medications (8.40 vs. 11.44, p<0.0001) than non-CDHP. Inpatient (p=0.01), outpatient (p<0.0001), prescription (p<0.0001), and total health care costs (p=0.0002) were also lower in CDHP members as compared to non-CDHP members. Logistic regression results suggest that younger age (age 18-34 years old) (OR: 16.16), living in the western United States (OR: 2.32), a lower CCS (OR: 0.86), and fewer hospitalizations (OR: 0.73) in the 12 month period prior to plan selection were significantly associated with CDHP selection. Conclusion: In this population, employees selecting the CDHP were associated with younger age, fewer comorbidities, western US residency, and lower prior health care utilization. This result reinforces the importance of selection adjustments in CDHP analyses.