Difference Between Users and Nonusers of a Patient Portal in Health Behaviors and Outcomes: Retrospective Cohort Study

BACKGROUND: Patient portals are frequently used in modern health care systems as an engagement and communication tool. An increased focus on the potential value of these communication channels to improve health outcomes is warranted. OBJECTIVE: This paper aimed to quantify the impact of portal use on patients' preventive health behavior and chronic health outcomes. METHODS: We conducted a retrospective, observational cohort study of 10, 000 patients aged 50 years or older who were treated at the University of Pennsylvania Health System (UPHS) from September 1, 2014, to October 31, 2016. The data were sourced from the UPHS electronic health records. We investigated the association between patient portal use and patients' preventive health behaviors or chronic health outcomes, controlling for confounders using a novel cardinality matching approach based on propensity scoring and a subsequent bootstrapping method to estimate the variance of association estimates. RESULTS: Patient-level characteristics differed substantially between portal users, comprising approximately 59. 32% (5932/10000) of the cohort, and nonusers. On average, users were more likely to be younger (63. 46 years for users vs 66. 08 years for nonusers), white (72. 77% 4317/5932 for users vs 52. 58% 2139/4068 for nonusers), have commercial insurance (60. 99% 3618/5932 for users vs 40. 12% 1632/4068 for nonusers), and have higher annual incomes (US 74, 172/year for users vs US 62, 940/year for nonusers). Even after adjusting for these potential confounders, patient portal use had a positive and clinically meaningful impact on patients' preventive health behaviors but not on chronic health outcomes. CONCLUSIONS: This paper contributes to the understanding of the impact of patient portal use on health outcomes and is the first study to identify a meaningful subgroup of patients' health behaviors that improved with portal use. These findings may encourage providers to promote portal use to improve patients' preventive health behaviors.