Medication adherence improvement similar for shared decision-making preference or longer patient-provider relationship

Background: While increasing evidence supports the beneficial effects of shared decision making (SDM) on patient outcomes, the mechanisms underlying this relationship is unclear. This study evaluated length of the patient-provider relationship as one potential factor that may explain how SDM affects medication adherence in patients with hypertension. Methods: An observational study of 75 hypertensive patients and 27 providers in 3 primary care practices in New York City. A single-item measure assessed patients’ preferences for decision-making style at baseline; medication adherence was collected over the 3-month study with an electronic monitoring device. Length of the relationship was measured as the number of years with the provider, and dichotomized as less than or greater than 1 year with the provider. Two generalized linear mixed models were conducted to determine whether the SDM-adherence association was modified by length of the relationship. Results: Most patients were Black and women, and 64% were seeing the same provider >1 year. Providers were mostly White women and have been at the clinic for 6 years. In the main-effects model, patients were more likely to exhibit better adherence when they preferred shared and active decision-making styles as compared with those who preferred a passive style (B 15.87 [Standard Error [SE]: 6.62], P .02; and B 22.58 [SE:7.62], P .004, respectively). In Model 2, the relative importance of SDM on adherence decreased as years with the provider increased (t₍₄₈₎ 2.13; P .04). Conclusion: The benefits of SDM over passive decision making on medication adherence were reduced with increasing years of the patient-provider relationship. Having an established relationship with the provider may have a positive impact on medication adherence that is comparable to relationships high in SDM.