U.S. emergency departments visits resulting from poor medication adherence: 2005-07.

OBJECTIVES

To describe characteristics and trends for emergency department visits related to medication nonadherence and to identify associations between patient characteristics and emergency department visits related to medication nonadherence.

DESIGN

Retrospective cross-sectional study.

SETTING

National Hospital Ambulatory Medical Care Survey (NHAMCS) from 2005 to 2007.

PATIENTS

Patients who had an emergency department visit for medication nonadherence.

INTERVENTION

NHAMCS data were weighted to yield national estimates of emergency department visits related to medication nonadherence. Descriptive frequencies were calculated for visits related and unrelated to medication adherence. A binary logistic regression model was used to identify covariates for nonadherence.

MAIN OUTCOME MEASURES

National estimates of emergency department visits related to medication nonadherence.

RESULTS

An estimated 456,209 ± 68,940 (mean ± SD) nonadherence-related visits occurred. Of visits related to nonadherence, 29% resulted from mental health disorders. Significant covariates of nonadherence-related visits included age, payment source, and primary diagnosis. Visits for patients with mental illness (odds ratio 22.74 [95% CI 14.68-34.20]), type 2 diabetes (15.80 [5.20-48.06]), nondependent abuse of drugs (11.85 [3.83-36.65]), or essential hypertension (11.06 [3.99-30.61]) were significantly associated with the probability that an emergency department visit was related to nonadherence. More than 20% of emergency department visits related to medication nonadherence resulted in hospital admission, whereas only 12.7% of visits unrelated to nonadherence resulted in hospital admission ( P < 0.0001).

CONCLUSION

Medication nonadherence is an important problem. Targeting patients at high risk for nonadherence, especially patients with mental illness, may improve medication adherence and prevent future emergency department visits.