Associations between antidepressant adherence and shared decision-making, patient-provider trust, and communication among adults with diabetes: diabetes study of Northern California (DISTANCE)

Abstract

Background: Depression and adherence to antidepressant treatment are important clinical concerns in diabetes care. While patient-provider communication patterns have been associated with adherence for cardiometabolic medications, it is unknown whether interpersonal aspects of care impact antidepressant medication adherence.

Objective: To determine whether shared decision-making, patient-provider trust, or communication are associated with early stage and ongoing antidepressant adherence.

Design: Observational new prescription cohort study.

Setting: Kaiser Permanente Northern California.

Patients: One thousand five hundred twenty-three adults with type 2 diabetes who completed a survey in 2006 and received a new antidepressant prescription during 2006-2010.

Measurements: Exposures included items based on the Trust in Physicians and Interpersonal Processes of Care instruments and the Consumer Assessment of Healthcare Providers and Systems (CAHPS) communication scale. Measures of adherence were estimated using validated methods with physician prescribing and pharmacy dispensing data: primary non-adherence (medication never dispensed), early non-persistence (dispensed once, never refilled), and new prescription medication gap (NPMG; proportion of time without medication during 12 months after initial prescription).

Results: After adjusting for potential confounders, patients' perceived lack of shared decision-making was significantly associated with primary non-adherence (RR = 2.42, p < 0.05), early non-persistence (RR = 1.34, p < 0.01) and NPMG (estimated 5% greater gap in medication supply, p < 0.01). Less trust in provider was significantly associated with early non-persistence (RRs 1.22-1.25, ps < 0.05) and NPMG (estimated NPMG differences 5-8%, ps < 0.01).

Limitations: All patients were insured and had consistent access to and quality of care.

Conclusions: Patients' perceptions of their relationships with providers, including lack of shared decision-making or trust, demonstrated strong associations with antidepressant non-adherence. Further research should explore whether interventions for healthcare providers and systems that foster shared decision-making and trust might also improve medication adherence.

Figure 1

Flowchart of new antidepressant user cohort.

Figure 2

Directed acyclic graph demonstrating covariate selection to estimate the effect of patient–provider relationship variables on antidepressant adherence. Shaded box: variable included in multivariate analyses. White box: variable excluded as potential confounder, and therefore not included in multivariate analyses. Solid arrow: causal pathways that do not confound the association between patient–provider relationship variables and antidepressant adherence. Dotted arrow: causal pathways that potentially confound the association between patient–provider relationship variables and antidepressant adherence in unadjusted analyses, but do not serve as confounders in multivariate models that include the variables identified in the shaded boxes. A directed acyclic graph was constructed based on published literature to illustrate the relationships between variables associated with patient–provider relationship quality and antidepressant adherence. All of the variables represented were available in the DISTANCE data set. An established process for analysis of a directed acyclic graph was applied to identify which of these variables were potential confounders of the association between patient–provider relationship variables and antidepressant adherence. This analysis revealed that adjustments for the variables in the shaded boxes (age, gender, race/ethnicity, education, and health literacy) were necessary and sufficient to include in the analysis as covariates, while variables in the white boxes were excluded as covariates. The causal relationships shown in the grey dotted arrows are accounted for by adjustment for the identified covariates (age, gender, race/ethnicity, education, and health literacy), and therefore, the relationships shown in dotted lines do not confound the association between patient–provider relationship and antidepressant adherence. The remaining causal pathways (solid arrows) do not require adjustment because they do not function as confounders. This is visualized in the graph because variables with causal links to the independent variable (English proficiency and PCP choice have solid arrows to patient–provider relationship variables) do not have direct causal pathways to the dependent variable (there are no solid arrows from these variables to antidepressant adherence). Likewise, variables with causal associations with the dependent variable (all other variables in white boxes have solid arrows to antidepressant adherence) do not have causal associations with the independent variable (these variables do not have solid arrows terminating at patient–provider relationship variables).