Health Literacy and Antidepressant Medication Adherence Among Adults with Diabetes: The Diabetes Study of Northern California (DISTANCE)

ABSTRACT

BACKGROUND

Previous studies have reported that health literacy limitations are associated with poorer disease control for chronic conditions, but have not evaluated potential associations with medication adherence.

OBJECTIVE

To determine whether health literacy limitations are associated with poorer antidepressant medication adherence.

DESIGN

Observational new prescription cohort follow-up study.

PARTICIPANTS

Adults with type 2 diabetes who completed a survey in 2006 and received a new antidepressant prescription during 2006–2010 (N = 1,366) at Kaiser Permanente Northern California.

MAIN MEASURES

Validated three-item self-report scale measured health literacy. Discrete indices of adherence based on pharmacy dispensing data according to validated methods: primary non-adherence (medication never dispensed); early non-persistence (dispensed once, never refilled); non-persistence at 180 and 365 days; and new prescription medication gap (NPMG; proportion of time that the person is without medication during 12 months after the prescription date).

KEY RESULTS

Seventy-two percent of patients were classified as having health literacy limitations. After adjusting for sociodemographic and clinical covariates, patients with health literacy limitations had significantly poorer adherence compared to patients with no limitations, whether measured as early non-persistence (46 % versus 38 %, p < 0.05), non-persistence at 180 days (55 % versus 46 %, p < 0.05), or NPMG (41 % versus 36%, p < 0.01). There were no significant associations with primary adherence or non-persistence at 365 days.

CONCLUSIONS

Poorer antidepressant adherence among adults with diabetes and health literacy limitations may jeopardize the continuation and maintenance phases of depression pharmacotherapy. Findings underscore the importance of national efforts to address health literacy, simplify health communications regarding treatment options, improve public understanding of depression treatment, and monitor antidepressant adherence.

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Acknowledgements

This research was supported by funding from the National Institutes of Health (R01-DK080726, R01-DK081796, P30-DK092924, and NCATS Grant KL2 TR000421). This research reported in this manuscript was presented at the annual meeting of the Academy of Psychosomatic Medicine in Atlanta GA, November 2012.

Conflict of Interest

Dr. Katon has received honoraria for CME lectures from Pfizer, Forest, and Eli Lilly and is on the advisory board for Eli Lilly. The authors report no other potential conflicts of interest.

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Correspondence to Amy M. Bauer MD, MS.

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Sensitivity analyses demonstrating the associations between health literacy limitations, race/ethnicity, and antidepressant medication adherence (DOCX 31 kb)

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Bauer, A.M., Schillinger, D., Parker, M.M. et al. Health Literacy and Antidepressant Medication Adherence Among Adults with Diabetes: The Diabetes Study of Northern California (DISTANCE). J GEN INTERN MED 28, 1181–1187 (2013). https://doi.org/10.1007/s11606-013-2402-8

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KEY WORDS

  • health literacy
  • medication adherence
  • antidepressive agents
  • diabetes mellitus
  • healthcare disparities