Reducing the health risks of diabetes: how self-determination theory may help improve medication adherence and quality of life.

Purpose: The purpose of this study is to apply the self-determination theory (SDT) model of health behavior to predict medication adherence, quality of life, and physiological outcomes among patients with diabetes.

Methods: Patients with diabetes (N = 2973) receiving care from an integrated health care delivery system in 2003 and 2004 were identified from automated databases and invited to participate in this study. In 2005, patients responded to a mixed telephone-and-mail survey assessing perceived autonomy support from health care providers, autonomous self-regulation for medication use, perceived competence for diabetes self-management, medication adherence, and quality of life. In 2006, pharmacy claims data were used to indicate medication adherence, and patients' non-high-density lipoprotein (HDL) cholesterol, A1C, and glucose levels were assessed.

Results: The SDT model of health behavior provided adequate fit to the data. As hypothesized, perceived autonomy support from health care providers related positively to autonomous self-regulation for medication use, which in turn related positively to perceived competence for diabetes self-management. Perceived competence then related positively to quality of life and medication adherence, and the latter construct related negatively to non-HDL cholesterol, A1C, and glucose levels.

Conclusions: Health care providers' support for patients' autonomy and competence around medication use and diabetes self-management related positively to medication adherence, quality of life, and physiological outcomes among patients with diabetes.