Association between interpersonal continuity of care and medication adherence in type 2 diabetes: an observational cohort study.

Background: Prior studies have shown that, compared to patients with a low level of interpersonal continuity of care, patients with a high level of continuity of care have a lower likelihood of hospital admission and emergency department visits, and a higher likelihood of patient satisfaction. We sought to determine whether higher levels of continuity of care are associated with medication persistence and compliance among new users of oral antidiabetic treatment.

Methods: We conducted a medicoadministrative cohort study of new users of oral antidiabetics aged 18 years or more among people covered by the Quebec public drug plan. We excluded people with fewer than 730 days of treatment and those who had been in hospital for 275 days or more in the first or second year after initiation of antidiabetic treatment. We categorized continuity of care observed in the first year after treatment initiation as low, intermediate or high. The association between continuity of care and medication persistence and compliance was assessed using generalized linear models.

Results: In this cohort of 60 924 new users of oral antidiabetic treatment, compared to patients with a high level of continuity of care, those with an intermediate and a low level of continuity of care were less likely to be persistent (adjusted prevalence ratio 0.97 [95% confidence interval (CI) 0.96-0.98] and 0.96 [95% CI 0.95-0.97], respectively) and compliant (adjusted prevalence ratio 0.98 [95% CI 0.97-0.99] and 0.95 [0.94-0.97], respectively) with their antidiabetic treatment.

Interpretation: A higher level of interpersonal continuity of care was associated with a higher likelihood of drug persistence and compliance. Since the strength of this association was weak, further research is required to determine whether continuity of care plays a role in medication adherence.