Exposure to potentially harmful drug-disease interactions in older community-dwelling veterans based on the Healthcare Effectiveness Data and Information Set quality measure: who is at risk?

OBJECTIVES

To identify prevalence and risk factors for exposure to drug-disease interactions included in the Healthcare Effectiveness Data and Information Set (HEDIS) Drug-Disease Interaction (Rx-DIS) measure.

DESIGN

Cross-sectional retrospective database analysis.

SETTING

Outpatient clinics within the Department of Veterans Affairs (VA).

PARTICIPANTS

Individuals aged 65 and older who received VA outpatient care between October 1, 2003, and September 30, 2006.

MEASUREMENTS

Rx-DIS exposure based on the HEDIS measure was identified in VA patients with dementia, falls, and chronic renal failure using VA pharmacy and administrative databases. Factors associated with Rx-DIS exposure were examined, including demographic, health status, and access-to-care factors, including VA outpatient health services use and copayment status.

RESULTS

Of the 305,041 older veterans who met criteria for inclusion, the 1-year prevalence of Rx-DIS exposure was 15.2%; prevalence was 20.2% for dementia, 16.2% for falls, and 8.5% for chronic renal failure. Patients with high disease burden (physical, psychiatric, number of medications) were significantly more likely to have Rx-DIS exposure, regardless of condition. Hispanics and individuals with no copayments were more likely to have Rx-DIS exposure than whites or those with required copayments. There was variation in other predictors based on the type of Rx-DIS.

CONCLUSION

The prevalence of Rx-DIS was common in older VA outpatients. Future studies should examine the risk of Rx-DIS exposure on health outcomes using separate analyses for each type of Rx-DIS separately before combining all Rx-DIS into a single measure of exposure. Studies that examine the effectiveness of interventions to reduce Rx-DIS exposure will also be helpful in improving the quality of care for older adults.