Use of the Refill Function through an Online Patient Portal Is Associated with Improved Adherence to Statins in an Integrated Health System

Background: U.S. ambulatory health systems are currently implementing internet-based patient portals, which permit online interactions with the health care system, including making appointments, reviewing laboratory results, and refilling medications. These functions are integral to the “meaningful use” standards for health information technology stipulated in federal legislation, but their impact on health behaviors and outcomes remains unclear. Some have suggested that patient portal use increases patient activation, leading to better self-management behaviors such as medication adherence. Objective: To determine whether adherence to statin medications improved among patients who initiated use of an available patient portal to obtain refills. We examined changes in adherence pre- and post- initiation of online refills, comparing those who initiated online refills (“exposed”) to reference patients who also used the patient portal, but not the refill function specifically. Methods: In this observational cohort study within an integrated healthcare delivery system (Kaiser Permanente Northern California), we studied patients with diabetes on statins who had registered for online portal access by 2010. We performed difference-in-differences analyses comparing changes in adherence among those who had versus had not initiated online refill function use. 8,705 subjects initiated use of the online refill function (“baseline”) within the study window, including “exclusive” and “occasional” users (i.e., completing all vs. some refills online, respectively). Using risk-set sampling, we temporally matched 9,055 “non-user” reference patients (i.e., portal users who never initiated use of the refill function). We calculated adherence to statins 12 months before and after baseline, assessed by medication gaps (% time with no pill supply). Non-adherence was defined by gaps of >20%. Our secondary outcome was % of patients with dyslipidemia (LDL ≥100 mg/dl). We specified modified least-squares regression models for differences in pre-post changes in non-adherence and dyslipidemia between refill function users, adjusting for age, sex, race/ethnicity, number of total medications, and outpatient visits, and accounting for secular trends. Results: 22% of the cohort was non-adherent at baseline. In adjusted models, non-adherence declined 6% (95% CI: 5-8%; p-value<0.001) in absolute terms after initiating exclusive use of the refill function. Among patients non-adherent to statins at baseline, the risk of dyslipidemia also decreased 6% (95% CI 3-9%; p-value= 0.001) for exclusive refill function users. These improvements in non-adherence and dyslipidemia were not observed among those initiating occasional use of the portal to refill medications. Conclusions: We observed modest but clinically substantive declines in rates of medication non-adherence and dyslipidemia in patients who initiated use of a health portal to refill medications. For those who initiated use of online refills, adherence improved significantly compared to their own baseline adherence and compared to improvements in adherence among diabetes patients who used the patient portal but not online refills. Our results suggest that portals can improve the quality of chronic disease management via improved medication adherence. []