Objective: Patient portal use can support self-management and expanding mobile portal access can potentially increase use. We examined the association between adding mobile portal access and medication adherence and glycemic levels among patient with diabetes.

Research Design and Methods: Eligible patients were adults with diabetes in an integrated delivery system who filled an oral diabetes prescription at baseline (4/14-3/15), and who did not use insulin. For each study month (4/15-12/17), we categorized patients’ portal access status: never used, personal computer (PC) only, mobile only, or both PC and mobile (first four-months of any status change was categorized separately as a wash-out period). We measured adherence by monthly percent of days covered (PDC) with oral diabetes drugs. To examine glycemic control, we included the subset of patients with HbA1c results (72% of all patients). We assessed the association between portal access and study outcomes (PDC and HbA1c), using linear regression with patient-level fixed effects to account for unmeasured time-stable patient-level confounders, adjusting for temporal trend, and time-varying numbers of drugs and health events.

Results: Among study patients (N= 111,463), the proportion with PC only portal access decreased from 30% to 13%, while the proportion using both mobile and PC increased from 34% to 62%. At baseline, 71.6% of patients had PDC≥80% and 78.8% had HbA1c<8%. Gaining both mobile and PC access was associated with a 1.67 percentage point increase in PDC among those with no portal access initially, and a 0.50 percentage point increase in among those with PC only access initially. Adding both mobile and PC access was associated with a 0.13 reduction in A1c level among those with no portal access initially, and a 0.07 reduction among those with only PC access initially (N=80,072, all p<0.05).

Conclusions: The addition of mobile portal access is associated with higher medication adherence and improved glycemic control for patients with diabetes.


I. Graetz: None. J. Huang: None. B. Fireman: None. J. Hsu: None. M. Reed: None.


National Institute of Diabetes and Digestive and Kidney Diseases (R01DK085070 to M.R.)

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