Effects of continuity of care on medication duplication among the elderly.

Background: The effects of continuity of care on health care outcomes are well documented. However, little is known about the effect of continuity at the physician or the site level on the process of care for patients with multiple chronic conditions (MCCs).

Objective: The objective of this study was to examine the effects of physician continuity versus site continuity on duplicated medications received by patients with and without MCCs.

Research Design And Subjects: This study utilized a longitudinal design with an 8-year follow-up from 2004 to 2011 of patients aged 65 or older under a universal health insurance program in Taiwan (55,573 subjects and 389,011 subject-years). Generalized estimating equation models with propensity score method were conducted to assess the association between continuity and medication duplication.

Results: The rates of subjects receiving duplicated medications ranged from 40.38% to 43.50% with 1.45-1.62 duplicated medications during the study period. The findings revealed that better continuity, either at the physician level or the site level, was significantly associated with fewer duplicated medications. This study also indicated that the physician continuity had a stronger effect on medication duplication than did site continuity. Furthermore, the magnitude of the protective effect of continuity against duplicated medications increased when the patients had more chronic conditions [physician continuity: the marginal effect ranged from -10.7% to -52.9% (all P<0.001); site continuity: the marginal effect ranged from -0.4% (P=0.063) to -31.4% (P<0.001)].

Conclusion: Improving either physician continuity or site continuity may result in fewer duplicated medications, particularly for patients with MCCs.